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Essential Physics Activities on a Budget Price
Low Cost Physics Activities
Center for Mathematics and Science Education
Texas A&M University - College Station
(Note: This web page was constructed using Microsoft FrontPage 2002 and is best viewed using Internet Explorer)
Physics experiments/activities do not have to be costly in time or resources. Teachers also do not need to limit their equipment purchases to "high tech" or specialty materials sold exclusively through science supply catalogs. Many valuable data collection activities can be performed using inexpensive materials that may be purchased from local department, hardware, and/or toy stores. The activities contained in the chart below represent a few of what I personally consider the "best for the buck" when it comes to introductory physics' essential laboratory activities on a tight budget. I have used all of them in high school and/or introductory undergraduate physics courses.
Activities similar to these using a variety of materials may be found in numerous lab resource materials. The purpose of this web page is not to introduce new and/or unique lab activities, but to present some of the most common and valuable lab experiences involving real data collection in a format for use with inexpensive materials. Activity worksheet documents are presented in both PDF and Microsoft Word format so that they may be easily downloaded, printed, and/or modified according to the individual needs of each user.
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Essential Physics Activities on a Budget Price
Click on a MS Word or PDF "Worksheet Link" to download an experiment/activity worksheet. Click on the "To the Teacher" link to view suggestions and information regarding the activity, materials, and approximate costs. "Other Links" provides links to other web pages with activities/information/simulations related to the chosen physics topic (all links active as of 3/9/2004).
Activity Worksheet Link
To the Teacher Other Links
1 Precision of Lab Equipment MS Word, PDF link
link1 link2 link3
2 Constant and Relative Velocity MS Word, PDF link
link1 link2 link3
3 Motion Graphs (Virtual Activity) MS Word, PDF link
link1 link2 link3
4 Accelerated Motion MS Word, PDF linklink1 link2
link3
5 Free Fall (Virtual Activity) MS Word, PDF linklink1 link2
link3
6 Resultant Vectors MS Word, PDF linklink1 link2
link3
7 Softball Throw MS Word, PDF linklink1 link2
link3
8 Newton's 2nd Law (Virtual Activity 1) MS Word, PDF link
link1 link2 link3
9 Newton's 2nd Law (Virtual Activity 2) MS Word, PDF link
link1 link2 link3
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Essential Physics Activities on a Budget Price
10 The Pendulum MS Word, PDF linklink1 link2
link3
11 Sliding Friction MS Word, PDF linklink1 link2
link312 Forces in Equilibrium MS Word, PDF link link1 link2 link3
13 Work and the Inclined Plane MS Word, PDF link
link1 link2 link3
14 One-Dimensional Collisions (Virtual Activity) MS Word, PDF link
link1, link2, link3
15 Two-Dimensional Collisions (Virtual Activity) MS Word, PDF link
link1, link2, link3
16 Torque and Rotational Equilibrium MS Word, PDF link
link1 link2 link3
17 Power MS Word, PDF linklink1 link2
link3
18 Wave Modeling MS Word, PDF linklink1 link2
link319 "Slinky" Waves MS Word, PDF link link1 link2 link3
20 Ripple Tank (Virtual Activity) MS Word, PDF link
link1 link2 link3
21 Resonance: Speed of Sound MS Word, PDF link
link1 link2 link3
22 Palm Pipes and Chimes MS Word, PDF linklink1 link2
link3
23 Reflection in Plane Mirrors PowerPoint Slide link
link1 link2 link3
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Essential Physics Activities on a Budget Price
24 Full Length Mirrors MS Word, PDF linklink1 link2
link3
25 Curved Mirror Diagrams MS Word, PDF linklink1 link2
link3
26 Index of Refraction MS Word, PDF linklink1 link2
link3
27 Lens Diagrams MS Word, PDF linklink1 link2
link3
28 Images in Converging Lenses MS Word, PDF link
link1 link2 link3
29 Color MS Word, PDF linklink1, link2,
link3
30 Electrical Circuits and Conductivity MS Word, PDF link
link1 link2 link3
31 Ohm's Law MS Word, PDF linklink1 link2
link3
32 Light Bulb Circuits MS Word, PDF linklink1 link2
link3
33 Electrical Energy Costs MS Word, PDF linklink1, link2,
link3
34 Electromagnets MS Word, PDF linklink1 link2
link3
35 Electric Motors MS Word, PDF linklink1 link2
link3
36 Simulated Radioactive Decay MS Word, PDF link
link1 link2 link3
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Essential Physics Activities on a Budget Price
Recently developed video analysis technology offers an exciting and relatively inexpensive way to analyze many types of one and two-dimensional motion. Go to http://www.science.tamu.edu/CMSE/videoanalysis/index.htm to learn more about some of the currently available video analysis programs, including one free program that may be downloaded from an internet site linked to the page. Also linked to this site are 19 video clips of many types of motion commonly studied in introductory physics and physical science courses and suggestions for their use. The 36 activities linked to this page and the 19 video analysis activities provide an excellent way for an entire introductory level physics class to include 55 laboratory activities at an unbelievably low cost.
In addition to these activities and web site links, physics teachers of all levels may be interested in the following web sites offering tutorials, downloadable software, etc... :
Name Description URL Link
Graph Paper Printer Program Create numerous types of custom graph paper link
The Diagnoser Project
A web-based assessment program that serves as a formative diagnostic of student content knowledge link
MERLOT A search engine for science web sites link
NetLogo A modeling program useful for many science areas link Journal of Physics Teacher Education Online
Online journal directly related to issues in physics teaching and the preparation of physics teachers link
Singing Science Records "Cheesy" science songs from the 1950s and 1960s link
Physics 2000 Very comprehensive tutorial program link The Physics Classroom Very comprehensive tutorial program link
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Essential Physics Activities on a Budget Price
Conceptual Physics SURF
Informative site supplementing Paul Hewitt's Conceptual Physics textbook link
For more information or comments about this web page or its activities,
to suggest other activities, or to request a workshop or professional
development session demonstrating the use of the activities, please contact:
Joel A. Bryan, [email protected] (979) 458-0604
Center for Mathematics and Science Education
Texas A&M University - Mail Stop 4232
College Station, TX 77843-4232
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CMSE Phys
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Triple Beam Balance Record the mass, in grams, of three (3) common objects using the triple beam balance.
Object Mass, g
When using this triple beam balance to find mass, you should record your values to the nearest ______________ of a gram because __________________________________________ _______________________________________________________________________.
Spring Scale Record the weight, in Newtons, of three (3) common objects using the spring scale.
Object Weight, N
When using this spring scale to find weight, you should record your values to the nearest _________________ of a Newton because _____________________________________ _______________________________________________________________________.
Meter Stick Record the length of three (3) common objects using the meter stick.
Object Length, cm
When using this meter stick to measure length, you should record your values to the nearest _____________ of a centimeter because _________________________ _______________________________________________________________.
Write a letter to a person of your choice in which you explain the rules for recording volume values using as examples 3 beakers that are graduated in ones, in tens, and in hundreds of milliliters (mL). Include a sketch of each type beaker in your letter.
CMSE Phys
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CCoonnssttaanntt VVeelloocciittyy ((SSppeeeedd)) Objective: Measure distance and time during constant velocity (speed) movement. Calculate average velocity (speed) as the slope of a “Position vs. Time” graph. Equipment: battery operated vehicles, stopwatch, meter stick or measuring tape Procedure: 1. Complete the table by timing each vehicle as it travels the indicated distance. 2. Perform two time trials for each distance and take the average value as your accepted time. 3. Use the distances traveled and average time s to make a “Distance vs. Time” graph (always named as
“y vs. x”) using MS Excel. Label this and all graphs as directed in class. 4. Use the MS Excel “Add Trendline” function to draw the best straight lines through your data
points and to compute the “best fit” equations for the lines. 5. Record the equation for each line on the graph. The slope of each line, given with the units
associated with the y- and x-axes, is the average velocity (speed) of each vehicle. Use this information to write the speed of each vehicle on the graphs next to each line.
6. Print your graph or graphs.
Vehicle I Vehicle II Distance, meters Time Trials, seconds Time Trials, seconds
1 2 AVG. 1 2 AVG. 0 0 0 0 0 0 0
0.5 1.0 1.5 2.0 2.5 3.0
Questions: 1. Did each vehicle appear to maintain a constant velocity (speed)? _____ How can you tell by looking at a “position vs. time” graph if the velocity (speed) is constant? 2. How should the “position vs. time” graph of a faster car compare with the graph of a slower car?
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RReellaattiivvee VVeelloocciittyy ((SSppeeeedd)) In this portion of the lab, you will determine the relative velocity (speed) of your two vehicles as they 1) approach each other from opposite directions, and 2) as the faster vehicle approaches and catches up to the slower one from behind. 1) Based on the average speeds of the two vehicles that you determined in Part I, what do you expect
the relative speed of the vehicles to be as they approach each other from opposite directions? (i.e., At what rate should they close in on each other?) _______ Why?
2) What do you expect the relative speed to be as the faster vehicle catches up to the other one from behind? (i.e., At what rate does the faster one close in on the other?) _______ Why?
Relative Velocity (Speed) Approaching from Opposite Directions Procedure:
1. Place the vehicles facing each other the distance apart indicated in the table. 2. Turn on each vehicle, releasing them at the same instant. Record the time for the vehicles to
meet. Perform two trials and take the average value as your accepted time. 3. Make a graph of “Closing Distance vs. Time” for this procedure. Determine the equation of the
line that best fits these data points. The slope of this line will be the relative velocity (speed) of the two vehicles as they approach each other from opposite directions.
Time, seconds Closing
Distance, m Trial 1 Trial 2 Average Time,
seconds 0.0 0 0 0 0.5 1.0 1.5 2.0 2.5 3.0
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Relative Velocity (Speed) as Vehicle Approaches from Behind Procedure continued:
4. Now place the vehicles facing the same direction the distance apart indicated in the table. The faster vehicle should be the indicated distance behind the slower one.
5. Turn on each vehicle, releasing them at the same instant. Record the time for the faster vehicle to catch up to the slower one. Perform two trials and take the average value as your accepted time.
6. Make a graph of “Closing Distance vs. Time” for this procedure. Determine the equation of the best fit line for these data points. The slope of this line will be the relative velocity (speed) of the two cars as the faster vehicle approaches the slower one from behind.
Time, seconds Closing
Distance, m Trial 1 Trial 2 Time, seconds
0.0 0 0 0 0.20 0.40 0.60 0.80 1.00 1.20
Questions: 1. Compare your experimental relative speeds with the estimates you made earlier. 2. Do you think your method of calculating relative speeds (addition or subtraction of speeds) is
always valid regardless of the speeds of the two objects? ______ Comment on your answer.
3. List possible sources of error in this lab.
CMSE Phys
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Use the knowledge you gain from this simulation and class discussion to complete the parts of the table illustrating motion that the simulation will not run. Initial Position Initial Velocity Acceleration Sketch of
Position-Time Graph Sketch of
Velocity-Time Graph
0 Positive 0
0 Negative 0
0 0 Positive
0 0 Negative
Positive 0 Positive
Positive 0 Negative
Purpose: to examine and compare the shapes of position-time and velocity-time graphs for objects moving in one dimension Procedure: Use the simulation at the web site http://jersey.uoregon.edu/vlab/block/Block.html to complete the summary table illustrating shapes of graphs for objects experiencing one-dimensional motion.
CMSE Phys
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Initial Position Initial Velocity Acceleration Sketch of Position-Time Graph
Sketch of Velocity-Time Graph
Negative 0 Positive
Negative 0 Negative
0 Positive Positive
0 Positive Negative
0 Negative Positive
0 Negative Negative
Positive Positive 0
Positive Negative 0
Negative Positive 0
Negative Negative 0
Positive Positive Positive
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Initial Position Initial Velocity Acceleration Sketch of Position-Time Graph
Sketch of Velocity-Time Graph
Positive Positive Negative
Positive Negative Positive
Positive Negative Negative
Negative Positive Positive
Negative Positive Negative
Negative Negative Positive
Negative Negative Negative
0 0 0
Negative 0 0
Positive 0 0
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Questions:
1. What is indicated by a velocity-time graph that crosses the x-axis? 2. How can you tell by looking at a position-time graph whether or not the object was changing speed? 3. How can you tell by looking at a velocity-time graph whether or not the object was changing speed? 4. What is the effect of changing the initial position on position-time and velocity-time graphs? 5. What is represented by the y-intercept on a position-time graph? 6. What is represented by the y-intercept on a velocity-time graph? 7. What is represented by an x-intercept on a position-time graph? 8. What is represented by an x-intercept on a velocity-time graph? 9. No matter what the initial position and initial velocity are, the velocity-time graph of an object with a positive acceleration will always … 10. No matter what the initial position and initial velocity are, the velocity-time graph of an object with a negative acceleration will always … 11. No matter what the initial position and initial velocity are, the velocity-time graph of an object with no acceleration will always …
CMSE Phys
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AAcccceelleerraattiioonn DDoowwnn aann IInncclliinnee There is a well-known story that Galileo dropped two objects of different weights from the Leaning Tower of Pisa in order to show that all objects accelerate toward the Earth at the same rate, regardless of their weight as long as air resistance is negligible. Historians, however, are quite certain that Galileo never performed such an experiment. Galileo’s experiments with acceleration involved rolling balls down an inclined plane. He did this out of necessity because of hi s inability to make precise measurements of the small distances and short time intervals needed for measuring the acceleration of objects in free fall. The inclined plane’s angle could be adjusted until the time for the ball to roll to the end was long enough for even the crude time-measuring devices of his day to produce useful results. In this exercise, you will examine acceleration by measuring the time needed for an object to roll various distances down an inclined plane – much like Galileo did around 400 years ago.
Purpose:
1. Examine the acceleration of a object rolling down an inclined plane 2. Determine the shape of a “Distance vs Time” graph for an accelerating object 3. Determine the mathematical relationship between the distance and time an object travels
while it is accelerating
Materials:
inclined plane, marble, stopwatch, meter stick or measuring tape
Procedure:
1. Measure and mark from one end of the inclined plane the distances indicated in the data table.
2. Place your inclined plane on something (a book?) so that one end is slightly elevated. 3. Use the stopwatch to determine how much time is needed for the marble to roll each
indicated distance down the incline. Record this time in the data table. 4. Perform three time trials for each distance and average them. 5. Use MS Excel to make a graph of “Distance vs Time.” 6. Use the MS Excel “Add Trendline” function to draw and calculate the best-fit curve to your
data points. Place this on your graph. 7. Answer the questions at the end of this activity.
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Time, seconds Distance, meters Trial 1 Trial 2 Trial 3
Average Time, seconds
0.10 0.15 0.20 0.40 0.50 0.60 0.70 0.80 0.90 1.20 1.35 1.60 1.80
Questions:
1. How does a “distance vs time” graph of accelerated motion compare with a “distance vs time” graph of non-accelerated motion (constant velocity)?
2. How can you tell by looking at a “distance vs time” graph whether or not the object has constant or changing speed?
3. What does the shape of your graph and the “best-fit” equation tell us about the mathematical relationship between distance and time for a uniformly accelerating object?
4. When looking at his data, Galileo discovered that an object would travel 4 times as far (22) in twice the time, 9 times as far (32) in triple the time, 16 times as far in (42) in quadruple the time, etc... Use your graph to find the ….
CMSE Phys
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time to travel 0.40 m ____ time to travel 0.10 m ____ ratio = ____ time to travel 0.60 m ____ time to travel 0.15 m ____ ratio = ____ time to travel 0.80 m ____ time to travel 0.20 m ____ ratio = ____ time to travel 1.00 m ____ time to travel 0.25 m ____ ratio = ____ time to travel 1.20 m ____ time to travel 0.30 m ____ ratio = ____ time to travel 1.60 m ____ time to travel 0.40 m ____ ratio = ____ time to travel 0.90 m ____ time to travel 0.10 m ____ ratio = ____ time to travel 1.35 m ____ time to travel 0.15 m ____ ratio = ____ time to travel 1.80 m ____ time to travel 0.20 m ____ ratio = ____
5. Do your results seem to agree with Galileo’s discovery? _____ Why/Why not?
6. What could you do in order to experimentally test whether or not all objects accelerate at the same rate, regardless of their weight?
7. How do you think the angle of incline affects this experiment?
8. What should happen to the time values in your data table if the incline is made steeper?
9. What should happen to the ratios in question #4 if the incline is made steeper?
10. List possible sources of error in this lab.
CMSE Phys
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Data Table I Time, s 0.0 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10
Distance, m
Purpose:
1. Examine distance-time and velocity-time graphs of a freely falling object.
2. Determine the acceleration due to gravity of an object in "free fall."
Procedure:
1. Go to the web site http://jersey.uoregon.edu/vlab/AverageVelocity/index.html .
2. Complete Data Table I by running the simulation in order to determine through “trial and error” the distance the object falls during the specified times.
3. Use MS Excel to make a graph of "Total Distance Fallen vs. Time."
4. Use the “Add Trendline” function to determine and place the “best fit” equation on your graph.
5. Print your graph, making sure it is labeled properly.
6. How can you tell by looking at a position-time graph whether or not the object had a constant velocity (speed)?
CMSE Phys
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To find out how the velocity (speed) changed and obtain the acceleration as the object fell, you must first calculate average velocities (speeds) of specific time intervals. For convenience, you will calculate the average
velocity (speed) during every tenth of a second. You will then see how these speeds changed with time.
5. Subtract distances from Data Table I to find the distances the object fell during every tenth of a second. Record these distances in Data Table II as Interval Distances.
6. Calculate the average velocity (speed) during each of these intervals using the relationship average speed = distance/time. The time for each interval will be 0.10 s. Record these values in the data table.
7. Using the assumption that a freely falling object increases its speed uniformly, we can conclude that the average speed during the interval will equal the instantaneous speed at the time halfway through the interval. Therefore, the instantaneous velocity (speed) at time t = 0.15 s will be the same as the average velocity (speed) during the time from t = 0.10 s to t = 0.20 s.
Data Table II
Time Interval, s Time of Interval, s Interval Distance, m Average Velocity for Interval, m/s
Avg. Vel. = Inst. Vel. at Time…, s
0.00 - 0.10 0.10 0.05 0.10 - 0.20 0.10 0.15 0.20 - 0.30 0.10 0.25 0.30 - 0.40 0.10 0.35 0.40 - 0.50 0.10 0.45 0.50 - 0.60 0.10 0.55 0.60 - 0.70 0.10 0.65 0.70 - 0.80 0.10 0.75 0.80 - 0.90 0.10 0.85 0.90 - 1.00 0.10 0.95 1.00 - 1.10 0.10 1.05
CMSE Phys
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8. Use MS Excel and the last two columns in Data Table II to make a graph of “Instantaneous Velocity vs Time.”
9. Use the “Add Trendline” function to determine and place the “best fit” equation on your graph.
10. Print this graph, making sure it is labeled properly. Discussion Questions: 1. The slope of your “Instantaneous Velocity vs Time” graph should be the value of the object’s acceleration. The slope of our graph is __________. 2. Make a statement comparing your acceleration to the accepted value of 9.8 m/s/s. 3. Look at the equation for your “Total Distance Fallen vs Time” graph. How can you determine the value of the gravitational acceleration from that equation? 4. Even though this activity was performed using a computer simulation, your results may not be in exact agreement with the accepted value for gravitational acceleration. What are some reasons why an activity such as this might still have error in it? Extension Idea: Repeat this process simulating free fall on Mars or the Moon. (not required, but something else that could be done)
CMSE Phys
RReessuullttaanntt VVeeccttoorrss
PPaarrtt II.. Calculate the resultant vectors when the following sets of vectors are combined. Show all steps as directed in class and illustrated by this example. A = 40 N @ 30° SE Ax = 40 cos 30° = 34.64 Ay = - 40 sin 30° = - 20.00 B = 60 N @ 70° SW Bx = - 60 cos 70° = - 20.52 By = - 60 sin 70° = - 56.38
Rx = 14.12 Ry = - 76.38 R2 = Rx
2 + Ry2 = (14.12)2 + (- 76.38)2 = 6033.28, so R = 77.67 N
T = Tan-1 (Ry/Rx) = Tan-1 (76.38/14.12) = 79.53° SE Solution: R = 77.67 N @ 79.53° SE PPaarrtt IIII.. Using either the “head-to-tail” or “head-to-head” graphical method, construct the resultant vectors when these same sets of vectors are combined. Use a scale of 1.0 cm = 1.0 unit. Measure the magnitude and direction of the resultant and compare with your calculated resultant. Label all vectors as directed in class. 1. A = 35 N @ 60° NE, B = 50 N @ 20° NW 2. A = 70 m/s @ 60° SW, B = 50 m/s @ 70° NW 3. A = 40 m @ 60° SE, B = 80 m @ 30° NW 4. A = 15 lb @ 60° NE, B = 50 lb @ 20° SE 5. A = 35 N @ 40° SW, B = 65 N @ 20° NW, C = 65 N @ 20° NE 6. A = 75 N @ 10° NE, B = 50 N @ 20° NW, C = 65 N @ 70° SE
1
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Procedure:
Record the name of the person throwing the softball. Throw the ball and measure the distance, in feet, and the time, in seconds, the ball travels through the air and record these values in the appropriate place in the data table. Repeat this procedure until this portion of the data table is complete.
Use the formula dx = vxt to find the horizontal velocity, in ft/s, for each trial. Record these values in the data table.
To find the initial vertical velocity, vy, use the formula vy = gt, where g is the acceleration of gravity and t is the time for the upward trip of the ball only. Use g = 32 ft/s/s and one-half of the total time in the air. Record these values in the data table.
You now have the horizontal and vertical components of the initial velocity. Use the Pythagorean Theorem (v2 = vx2 + vy
2) to calculate the magnitude of the initial velocity in ft/s. Record these values in the data table. To convert these speeds from ft/s to mph, use the relationship that 1 mile = 5280 feet and 1 hour = 3600 sec. Record these values in the data table.
Divide the vertical velocity by the horizontal velocity and find the inverse tangent of this result to find the angle above the horizontal that the ball was thrown. Record these values in the data table.
The maximum height, in feet, the ball traveled above the release point is found by squaring the vertical velocity (in ft/s) and dividing by twice the acceleration of gravity (2 x 32 ft/s/s = 64 ft/s/s).
The initial velocity of a projectile may be found by measuring the amount of time it is in the air,
the horizontal distance it travels during that time, and applying these values to a few simple calculations.
2
DDaattaa TTaabbllee
Name HorizontalDistance,
feet
Time, seconds
HorizontalVelocity,
ft/s
Vertical Velocity,
ft/s
Velocity, ft/s
Velocity, mph
Angle, θ
Maximum height,
ft
CMSE Phys
1
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1. Run the simulation using the masses shown in Data Table I, using a mass of zero for the pulley.
2. Record the acceleration shown in the simulation.
3. Calculate the weights of the blocks. (Use g = 9.8 m/s/s when calculating the weights.)
4. The net force will be the difference in the weights (Blue weight – Red weight).
5. Make a graph of Acceleration vs Net Force when Total Mass is Constant.
6. Does the shape of your graph confirm the relationship between acceleration and net force that Newton’s Law predicts?
According to Newton’s 2nd Law, the acceleration of an object is inversely proportional to its total mass and directly proportional to the net force acting on it.
Go to the web site http://physics.bu.edu/~duffy/java/Rotation2.html . You will see a drawing identical to the one to the right. Run the simulation while adjusting the masses of the red and blue blocks in order to examine Newton’s Second Law.
For the first trials, you will keep a constant total mass of 10 kg. By “moving” mass from one side to the other, you will vary the net force.
CMSE Phys
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DDaattaa TTaabbllee II -- EExxppeerriimmeennttaall RReessuullttss:: CCoonnssttaanntt MMaassss
Block Mass, kg Block Weight, N Red Blue
Total Mass, kg Red Blue
Net Force, N Acceleration, m/s/s
1 9 2 8 3 7 4 6 5 5 6 4 7 3 8 2 9 1
1. Run the simulation using the masses shown in Data Table II, using a mass of zero for the pulley.
2. Record the acceleration shown in the simulation.
3. Calculate the weights of the blocks. (Use g = 9.8 m/s/s when calculating the weights.)
4. The net force will be the difference in the weights (Blue weight – Red weight).
5. Use MS Excel to make a graph of Acceleration vs Total Mass when the Net Force is Constant.
6. Does the shape of your graph confirm the relationship between acceleration and total mass that Newton’s Law predicts?
For these next trials, you will keep a constant net force of 9.8 N. By “adding” mass to each side of the pulley, you can maintain the same net force while varying the
total mass.
CMSE Phys
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DDaattaa TTaabbllee IIII -- EExxppeerriimmeennttaall RReessuullttss:: CCoonnssttaanntt NNeett FFoorrccee
Block Mass, kg Block Weight, N Red Blue
Total Mass, kg Red Blue
Net Force, N Acceleration, m/s/s
1 0 2 1 3 2 4 3 5 4 6 5 7 6 8 7 9 8
CMSE Phys
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• Go to the site http://webphysics.ph.msstate.edu/jc/library/4-7a/index.html . • Click on “Start Simulation.” • You will open a window identical to the one shown below. • Run the simulation while adjusting the mass of the wagon and the hanging mass
in order to examine Newton’s Second Law.
• According to Newton’s 2nd Law, the acceleration of an object is inversely
proportional to its total mass and directly proportional to the net force acting on it.
Part I:
For the first trials, you will keep a constant total mass of 200 g. By “moving” mass from the wagon to the hanger, you will vary the net force.
1. Run the simulation using the masses shown in the data table and setting the friction
coefficient to zero. 2. Record the acceleration shown in the simulation. How would you calculate these
values if they were not given to you in the simulation? 3. Calculate the weight of the hanging mass. (Use g = 9.8 m/s/s when calculating this
weight.)
CMSE Phys
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4. Since there is “no friction,” the net force is equal to the weight of the hanging mass. 5. Make a graph of Acceleration vs Net Force when Total Mass is Constant. 6. Does the shape of your graph confirm the relationship between acceleration and net
force that Newton’s 2nd Law predicts?
EExxppeerriimmeennttaall RReessuullttss:: CCoonnssttaanntt MMaassss
Mass, kg
Wagon Hanging Total Mass, kg
Net Force, N (Weight of the Hanging Mass)
Acceleration, m/s/s
0.199 0.001 0.200 0.175 0.025 0.200 0.150 0.050 0.200 0.125 0.075 0.200 0.100 0.100 0.200 0.075 0.125 0.200 0.050 0.150 0.200 0.025 0.175 0.200 0.001 0.199 0.200
Part II:
For these next trials, you will keep a constant net force of 0.49 N (by keeping a constant mass of 50 g on the hanger). By “adding” mass only to
the wagon, you can maintain this same net force while varying the total mass.
1. Run the simulation using the masses shown in the data table, again setting the friction coefficient to zero.
2. Record the acceleration shown in the simulation. How would you calculate these values if they were not given to you in the simulation?
3. Calculate the weight of the hanging mass. (Use g = 9.8 m/s/s when calculating this
weight.) 4. Since there is “no friction,” the net force is the weight of the hanging mass. 5. Make a graph of Acceleration vs Total Mass when the Net Force is Constant. 6. Does the shape of your graph confirm the relationship between acceleration and
net force that Newton’s 2nd Law predicts?
CMSE Phys
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EExxppeerriimmeennttaall RReessuullttss:: CCoonnssttaanntt NNeett FFoorrccee
Mass, kg
Wagon Hanging Total Mass, kg
Net Force, N (Weight of the Hanging Mass)
Acceleration, m/s/s
0.010 0.050 0.030 0.050 0.070 0.050 0.100 0.050 0.150 0.050 0.250 0.050 0.350 0.050 0.500 0.050 0.650 0.050 0.800 0.050 0.900 0.050
Questions:
1. How would you calculate the acceleration of the system if friction were present?
2. Suppose there is no friction. In order for the wagon on the table to move, the weight hanging over the side of the table must be at least…
3. Suppose friction is present. In order for the wagon on the table to move, the weight hanging over the side of the table must be at least….
4. Is it possible to obtain an acceleration equal to the gravitational acceleration if friction is not present? Why or why not?
CMSE Phys
1
TThhee SSiimmppllee PPeenndduulluumm Materials: light string, meter stick, stopwatch, various masses • Your simple pendulum will consist of a mass suspended by light thread from a point about which it can
freely swing. • The displacement of the pendulum will be the angle at which it is pulled back before release to swing. • The length is the distance from the point of suspension to the center of gravity of the mass. • You will measure the period (the time it takes for the pendulum bob to swing from one side to the other
and back again) while individually varying the mass, length, and angular displacement of the pendulum.
I. DOES MASS AFFECT THE PERIOD OF A PENDULUM?
A. Use a length of string between 0.60 m and 1.20 m. Tie a mass to the string. Pull the pendulum bob back about 30° and record the time it takes for the pendulum to make 10 complete cycles. Divide this time by 10 to get the period of the pendulum.
B. Record this information in DATA TABLE I. C. Now perform the same procedure, but use a different mass. Be sure to keep all other variables
EXACTLY the same as before. D. Repeat these steps for the other masses. Record all information in the data table.
II. DOES LENGTH AFFECT THE PERIOD OF A PENDULUM?
A. Find the period of the pendulum as you did above, but use the same mass and amplitude in each trial, while varying only the pendulum’s length.
B. Do this according to DATA TABLE II.
III. DOES AMPLITUDE AFFECT THE PERIOD OF A PENDULUM?
A. This time use a constant length and mass, but vary the amplitude (angle) through which the pendulum swings.
B. Find the period of the pendulum with initial amplitudes given in DATA TABLE III. C. Record all information in the data table.
Find the formula for the pendulum in your book and use your results to calculate the acceleration of gravity for each trial.
Objectives: 1) To determine if/how mass, length, and angular displacement affect the period of a simple pendulum 2) Use a simple pendulum to determine the acceleration of gravity
CMSE Phys
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DATA TABLE I – Variable Mass
Mass, g
Length, m
Amplitude, deg
Time, s 10 cycles
Period, s
g, m/s2
20 50 100 200 500
DATA TABLE II – Variable Length
Mass, g
Length, m
Amplitude, deg
Time, s 10 cycles
Period, s
g, m/s2
0.20 m 0.35 m 0.50 m 0.65 m 0.80 m 0.95 m 1.10 m 1.25 m 1.40 m DATA TABLE III – Variable Amplitude
Mass, g
Length, m
Amplitude, deg
Time, s 10 cycles
Period, s
g, m/s2
10 20 30 40 50
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Results: Make a graph of “Period vs Mass” using the results of Data Table I. Make a graph of “Period vs Length” using the results from Data Table II. Make a graph of “Period vs Amplitude” using the results of Data Table III. On each graph, write a statement commenting on the relationship between the period and the manipulated variable that is indicated by the shapes of the graphs. For example, you may find relationships that are directly proportional, inversely proportional, quadratic , square root, sinusoidal, or you may find no relationship at all. Write a summary paragraph describing what you learned about pendulums from this activity.
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SSlliiddiinngg FFrriiccttiioonn
Objectives: • determine the coefficient of sliding friction for wood on desk ,
rubber-soled shoe on dry floor, and rubber-soled shoe on wet floor • determine the relationship between friction force and surface area
Equipment: force scale, friction block, shoe, various masses, water Procedure:
““WWoooodd oonn DDeesskk -- WWiiddee SSiiddee””
1. Find the weight of your friction block using either the triple beam balance or your force scale.
2. Record the weight of the friction block in Data Table I.
3. Attach the force scale to the friction block and pull the scale horizontally with the desktop at a steady rate and record the average force reading in your data table under the column “Friction Force.”
4. Add some mass. Calculate this additional weight (use g = 10 m/s/s for each of the calculations) and record your findings in the Data Table. This total amount of weight will be known as the “Normal Force.” Pull the block as before to find the amount of friction force with this total weight.
5. Continue until Data Table I is completed with 5 total trials.
6. Calculate the “Friction Coefficient” by dividing the Friction Force by the Normal Force. This coefficient has no units since you are dividing Newtons by Newtons.
7. Find the average value of your friction coefficients and record beneath your data table.
8. Make a graph of “Friction Force vs. Normal Force.” Include the origin as one of your data points. Determine the best fit equation of your line and record on the graph. Notice how close the slope is to your average Friction Coefficient.
CMSE Phys
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““RRuubbbbeerr--ssoolleedd SShhooee oonn DDrryy FFlloooorr””
9. Repeat procedures 1-8 using the shoe on the dry floor for Data Table II – “Rubber-soled Shoe on Dry Floor.”
DDaattaa TTaabbllee II –– ““WWoooodd oonn DDeesskk -- WWiiddee SSiiddee””
Trial Block Weight, N
Additional Mass,
kg
Additional Weight,
N
Normal Force (Total Weight)
N
Friction Force,
N
Friction Coefficient
1 0 0 2 3 4 5
Average Friction Coefficient for “Wood on Desk” = __________
DDaattaa TTaabbllee IIII –– ““RRuubbbbeerr--ssoolleedd SShhooee oonn DDrryy FFlloooorr””
Trial Shoe Weight, N
Additional Mass,
kg
Additional Weight,
N
Normal Force (Total Weight)
N
Friction Force,
N
Friction Coefficient
1 0 0 2 3 4 5
Average Friction Coefficient for “Rubber-soled Shoe on Dry Floor” = __________
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10. Repeat procedures 1-8 using the shoe on a place where you have made the floor wet. Record the results in Data Table III – “Rubber-soled Shoe on Wet Floor.”
DDaattaa TTaabbllee IIIIII –– ““RRuubbbbeerr--ssoolleedd SShhooee oonn WWeett FFlloooorr””
Trial Shoe Weight, N
Additional Mass,
kg
Additional Weight,
N
Normal Force (Total Weight)
N
Friction Force,
N
Friction Coefficient
1 0 0 2 3 4 5
Average Friction Coefficient for “Rubber-soled Shoe on Wet Floor” = __________ Compare the friction coefficient of rubber on a dry floor with rubber on a wet floor. You will now repeat these procedures for finding the friction coefficient for wood on desk, but will use the “thin side” of the wood block. Since the “wide side” has approximately ______ times as much area as the “thin side,” most people would expect the friction on the “wide side” to be about _____ times as large.
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11. Perform these trials as before and record your results in Data Table IV - “Wood on Desk - Thin Side.”
DDaattaa TTaabbllee IIVV –– ““WWoooodd oonn DDeesskk –– TThhiinn SSiiddee””
Trial Block Weight, N
Additional Mass,
kg
Additional Weight,
N
Normal Force (Total Weight)
N
Friction Force,
N
Friction Coefficient
1 0 0 2 3 4 5
Average Friction Coefficient for “Wood on Desk – Thin Side” = __________
Questions:
1. How does the friction coefficient depend on the area of the surface in contact?
2. Why do you think this is so?
3. What factors do influence the amount of sliding friction? 4. Name some possible sources of error in this lab.
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5
DDaattaa TTaabbllee VV –– ““ oonn ””
Trial Block Weight, N
Additional Mass,
kg
Additional Weight,
N
Normal Force (Total Weight)
N
Friction Force,
N
Friction Coefficient
1 0 0 2 3 4 5
Average Friction Coefficient for “ on ” = __________
DDaattaa TTaabbllee VVII –– ““ oonn ””
Trial Block Weight, N
Additional Mass,
kg
Additional Weight,
N
Normal Force (Total Weight)
N
Friction Force,
N
Friction Coefficient
1 0 0 2 3 4 5
Average Friction Coefficient for “ on ” = __________
CMSE Phys
1
FFoorrcceess iinn EEqquuiilliibbrriiuumm
According to Newton’s First Law of Motion, an object remaining at rest even when forces are acting upon it does so because there is no net force acting on the object.
This means that the resultant or vector sum of all the forces acting on the object is zero. An object in this state or condition is said to be “in equilibrium.”
In this lab exercise, you will apply forces to an object in such a way that the object
remains stationary. You will then verify that the resultant force is indeed zero.
1. Place the ring (washer) over the origin of your polar grid paper with the force scales attached in the positions indicated in the data table. 2. Pull each scale in the indicated directions. Pull so that the ring remains centered over the origin. At least one of your forces should be over 15.0 N. 3. Record the reading on each scale. Record to the nearest tenth of a Newton when using these
0-20 N scales. 4. Calculate the horizontal (x) and vertical (y) components of each force. 5. Sum the components. Record these values in the data tables. 6. Use the Pythagorean Theorem and the inverse tangent function to calculate each resultant
force’s magnitude and direction. Your resultant magnitudes should be close to zero.
Force (Newtons)
Angle (Degrees)
Horizontal Component
Vertical Component
A 0 (East) B 110 (70° NW) C 200 (20° SW)
Sum of Components = Resultant =
Force (Newtons)
Angle (Degrees)
Horizontal Component
Vertical Component
A 45 B 135 (45° NW) C 270 (South)
Sum of Components = Resultant =
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Force (Newtons)
Angle (Degrees)
Horizontal Component
Vertical Component
A 80 B 210 (30° SW) C 280 (80° SE)
Sum of Components = Resultant =
Force (Newtons)
Angle (Degrees)
Horizontal Component
Vertical Component
A 60 B 190 (10° SW) C 340 (20° SE)
Sum of Components = Resultant =
Force (Newtons)
Angle (Degrees)
Horizontal Component
Vertical Component
A 25 B 180 (West) C 335 (25° SE)
Sum of Components = Resultant =
Join with another group for this final trial. Force
(Newtons) Angle
(Degrees) Horizontal Component
Vertical Component
A 0 (East) B 20 C 120 (60° NW) D 240 (60° SW) E 315 (45° SE)
Sum of Components = Resultant =
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Graph constructed using a free graphing program found at http://www.mathematicshelpcentral.com/graph_paper.htm
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TToorrqquuee aanndd RRoottaattiioonnaall EEqquuiilliibbrriiuumm
In this lab, you will pull on a meter stick at various locations until the meter stick is “at rest” (neither translating nor rotating, which is a state of equilibrium). You will then verify the two conditions for equilibrium by examining the total amounts of upward and downward force and the total amounts of clockwise and counterclockwise torques.
1. Place the scales at the locations indicated. Scales A and C should pull in the same direction, with scale B (and D if given) pulling in the opposite direction. Place arrows on the meter stick diagram in order to show the location of each force. 2. Record the readings on each scale when equilibrium is achieved. 3. Use the “zero” end of the meter stick as your pivot point and calculate your torques (in this lab, “torque = force x location” since the location is the distance from the zero end). 4. Sum the forces and torques. Look at each of these values to see how well each trial verified the
conditions for equilibrium. I.
Scale Location, cm
Force, N
Up or Down? Torque, N•cm
cw or ccw?
A 20 B 50 C 80
0 cm 100 cm
ΣFup ΣFdown Στcw Στccw
II.
Scale Location, cm
Force, N Up or Down? Torque,
N•cm cw or ccw?
A 30 B 60 C 90
0 cm 100 cm
ΣFup ΣFdown Στcw Στccw
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III.
Scale Location, cm
Force, N Up or Down? Torque,
N•cm cw or ccw?
A 10 B 70 C 90
0 cm 100 cm
ΣFup ΣFdown Στcw Στccw
IV.
Scale Location, cm
Force, N
Up or Down? Torque, N•cm
cw or ccw?
A 25 B 40 C 70 D 80
0 cm 100 cm
ΣFup ΣFdown Στcw Στccw
V.
Scale Location, cm
Force, N Up or Down? Torque,
N•cm cw or ccw?
A 5 B 50 C 70 D 85
0 cm 100 cm
ΣFup ΣFdown Στcw Στccw
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PPOOWWEERR
A simple way to measure the power output of a person is to measure the time it takes the person to walk/run up a flight of stairs (or bleachers). In this experiment you will measure your power in climbing a flight of stairs and compare it to the power of your classmates. 1. Measure the height from the ground to the second floor/top of stairs (or other desired position).
2. Record your name and weight (in pounds) or use the scale to obtain your mass (in kilograms). 3. Measure the time it takes to run (or walk) to the desired height.
4. Share your values with your classmates and record their values in the data table.
After everyone has run (or walked) up the stairs, perform the following calculations to find the power. 1. Convert a weight from pounds to Newtons by dividing the weight in pounds by 2.2 to get the mass in kilograms.
Then multiply the mass (in kilograms) by 9.8 m/s/s to obtain the weight in Newtons.
2. Find the amount of work (in Joules) each person has done by multiplying their weight (in Newtons) by the height ascended (in meters).
3. Find the power (in Watts) using the formula: Power (W) = Work (J) / time (sec).
4. Find the equivalent horsepower by dividing the power (in Watts) by 746 because 1 horsepower equals 746 Watts.
5. Record all values in the data table.
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**** Alternative Procedure ****
Find the power output in doing work on an object (a brick, book bag, etc...). Weigh the object and carry it up the stairs or pull it up using a rope. Calculate the power exactly as described above. In the data table, write “your name carrying or lifting item” under the “Name” column.
Questions:
1. The work done in traveling up the flight of stairs (or lifting an object) depends only on …
2. Power depends on …
3. How would the work done in lifting a load up three flights of stairs compare to the work done in lifting the same load up one flight of stairs?
4. What happens to the power output if the same amount of work is done in one-half the time?
5. What happens to the power output if the same amount of work is done in twice the time?
6. How much work (energy) is needed to keep a 100 W light bulb lit each second?
7. How much work (energy) is needed to keep a 100 W light bulb lit each minute?
8. How much work (energy) is needed to keep a 100 W light bulb lit each hour?
9. The same amount of work (energy) needed to keep the 100 W light bulb lit for one hour could be used to lift a 2000 kg
SUV to what height?
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Name Weight (lbs)
Mass (kg)
Weight (N)
Height (meters)
Work (Joules)
Time (sec)
Power (Watts)
Power (hp)
PPOOWWEERR DDAATTAA TTAABBLLEE
CMSE Phys
WWaavvee MMooddeelliinngg
Purpose:
• model transverse and longitudinal waves • identify and measure wave characteristics
Materials:
• “butcher” paper ( 5-7 feet long, 2-3 feet wide), stopwatch, meter stick, markers Procedure:
Each group should have three members. Place the large sheet of butcher paper on the lab table. One group member steadily pulls the paper across the table while another member moves the marker back and forth over the paper. The arm should swing freely as a pendulum. The third group member uses the stopwatch to measure the amount of time needed to sketch the wave motion across the entire length of paper. A transverse wave may be modeled when the marker moves back and forth perpendicularly to the direction of the moving paper. A longitudinal wave may be modeled when the marker moves back and forth across the paper parallel to its direction of movement. If done carefully, you should see nice consistent shapes for these two wave models.
For each of these two wave models:
• Record the total time of the wave motion on the paper. • Label, measure, and record the wavelength of the wave. • Label, measure, and record the amplitude of the wave. • Count the number of complete vibrations and divide by the total time to obtain
the frequency of the wave. • Divide the total time by the number of complete vibrations to obtain the period
of the wave. • Find the wave’s velocity by measuring the total distance the wave traveled and
dividing this value by the total time. • Now calculate the wave’s velocity by multiplying the recorded frequency of the
wave by the measured wavelength. Compare this result with the velocity obtained using the total distance and time.
Show all work and calculations on the butcher paper.
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PPUULLSSEESS OONN AA CCOOIILL SSPPRRIINNGG
TRANSVERSE PULSES
A. Send a transverse pulse down a stretched large coil spring. Observe the motion of the spring’s coils. Draw a sketch of the pulse traveling down the spring. Why is this pulse called a transverse pulse? B. Observe the speed of the pulse while varying the pulse amplitude. What happens to the speed of the pulse as the amplitude changes? C. Observe the speed of the pulse while varying the tension in the spring. What do you notice about the pulse speed with respect to changes in tension? D. Does the stretched spring under different tensions represent the same or different transmitting media? E. Maintain a constant tension and send continuous wave trains of varying frequencies down the spring. What happens to the wavelength as the frequency increases?
Coiled springs are excellent materials for analyzing a variety of wave behaviors. In this activity, you will examine transverse and longitudinal pulses, fixed- and free-end reflections, constructive and destructive interference, standing waves, and the behavior of waves when they reach new transmitting media.
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WAVE INTERFERNCE
F. Send two pulses of approximately the same amplitude from opposite ends of the spring toward each other on the same side of the spring. What do you observe? Do the two disturbances “bounce off” each other or pass right through each other? What do you notice when the pulses “overlap”? Draw sketches showing the pulses, labeled “A” and “B”, before, during, and after they meet. G. Send two pulses of approximately the same amplitude from opposite ends of the spring toward each other on opposite sides of the spring. What do you observe? Do the two disturbances “bounce off” each other or pass right through each other? What do you notice when the pulses “overlap”? Draw sketches showing the pulses (labeled “A” and “B”) before, during, and after they meet.
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WAVE REFLECTION
H. Hold the spring firmly down in place at the far end and send a pulse down the spring. Describe and illustrate your observations of reflection from this “fixed end.” I. Attach and hold a light string on one end of the spring and send a pulse from the other end. Describe and illustrate your observations of reflection from this “free end.”
WAVE BEHAVIOR AT MEDIA BOUNDARIES
J. Attach the two springs together and send a pulse from the large spring. Record your observations. K. What happens to the wave speed when the pulse goes from the large spring to the small spring? .…from the small spring into the large spring? L. Did you notice any reflection when the pulse reached the junction where the two springs were connected? Did more of the wave seem to be transmitted or reflected? Think of a common example where light waves partially reflect and partially transmit when they reach the boundary of the transmitting media.
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STANDING WAVES M. While holding one end of the large spring firmly in place, move the other end of the spring continuously back and forth to send a continuous wave train down the spring. Adjust your frequency until a standing wave with two “loops” is obtained. Now change your frequency of vibration until more loops are formed. Since the speed of the wave remains constant (do you know why?), shaking the spring with a higher frequency does what to the wavelength? In order to obtain standing waves with more loops when the speed of the wave is constant, what must be done to the frequency of vibration? How could you determine the wavelength of the wave when a standing wave pattern is observed? Draw sketches of standing waves having one, two, three, and four loops. Indicate on your sketches how the wavelength could be measured.
LONGITUDINAL PULSES
N. Stretch the large spring and send a longitudinal pulse down the spring. Observe the motion of the spring coils. Draw a sketch of the pulse traveling down the spring. Why is this pulse called a longitudinal pulse? Note: Wave properties such as diffraction and refraction unfortunately cannot be observed with coiled springs.
CMSE Phys
1
WWaavveess iinn aa RRiippppllee TTaannkk:: AA VViirrttuuaall AAccttiivviittyy
Go to the site http://www.falstad.com/oscgrid/ . A “Ripple Tank Applet” window will open that runs a simulation of waves generated in a ripple tank. By “clicking on” any or all of the three task bars in the upper right hand corner of the applet window, you can change the type and number of wave sources. The third task bar allows you to use the mouse to edit the waves or walls (barriers). You can adjust the speed, resolution, frequency, brightness, and/or damping of the wave simulation to obtain a clearer representation of the wave phenomena. A complete and detailed set of directions for how to use this simulation is linked to the web page. Your task is to use this web site to identify and investigate various wave properties and characteristics. You will hand in pictorial representations of…
1. Circular Wave a. long wavelength b. shorter wavelength
2. Plane Wave a. long wavelength b. shorter wavelength
3. Reflection a. Plane Wave Off Angled Straight Barrier b. Plane Wave Off Concave (Parabolic) Barrier c. Circular Wave Off Straight Barrier
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2
4. Diffraction a. Plane Wave Around a Barrier b. Plane Wave Through an Opening c. Circular Wave Around a Barrier d. Circular Wave Through an Opening
5. Refraction of a Plane Wave 6. Refraction due to Temperature Gradient (simulates sound wave over lake) 7. Interference
a. Two Circular Waves (wide spacing between sources) b. Two Circular Waves (closer spacing between sources) c. One Plane and One Circular Wave (this is a tricky one to simulate!) d. Single Slit (plane wave) e. Double Slit (plane wave) f. Triple Slit (plane wave)
8. Doppler Effect 9. Beats 10. Something else you find really interesting
You have two options for completing this assignment:
1. Make small (about 4 in. x 4 in.) sketches with colored pens/pencils…OR… 2. Use a “screen capture” program to copy and paste the actual images from
the applet window into a document (MS Word with text boxes, for example), which can then be saved and printed.
You can download a free trial version of an easy to use screen capture program at http://www.etrusoft.com/. The image shown on this handout was “captured” using this program. You can probably fit 6 diagrams/sketches on each side of a page. Be sure to label each sketch.
CMSE Phys
1
RReessoonnaannccee:: TThhee SSppeeeedd ooff SSoouunndd –– CClloosseedd TTuubbee
Trial Tuning Fork Frequency,
Hz
Resonant Tube Length,
m
Tube Diameter,
m
Wavelength, m
Experimental Speed of Sound,
m/s
Air Temp,
°C
Accepted Speed of Sound,
m/s
Percent Error,
% 1 2 3 4
FOR EACH TRIAL 1. Calculate the wavelength of each resonant sound wave. Show the formula and calculations in the space below. 2. Calculate the experimental speed of sound. Show the formula and calculations in the space below.
3. Use the air temperature to find the accepted speed of sound. Show the formula and calculations in the space below. 4. Calculate the % error for each speed of sound trial. Show the formula and calculations in the space below.
CMSE Phys
2
YYoouu wwiillll nnooww uussee tthhee pphheennoommeennoonn ooff rreessoonnaannccee ttoo ddeetteerrmmiinnee tthhee ffrreeqquueennccyy ooff aann uunnmmaarrkkeedd ttuunniinngg ffoorrkk..
Trial
Resonant Tube Length,
m
Tube Diameter,
m
Wavelength, m
Air Temp, °C
Accepted Speed of Sound,
m/s
Calculated Tuning Fork Frequency,
Hz 1 2
FOR EACH TRIAL 1. Find the resonant tube length and calculate the wavelength of each resonant sound wave. Show the formula and calculations
in the space below. 2. Use the air temperature to find the accepted speed of sound. Show the formula and calculations in the space below. 3. Use the experimental wavelength and temperature-based accepted speed of sound to calculate the frequency of your tuning
fork. Show the formula and calculations in the space below .
4. List sources of error in this lab.
CMSE Phys
1
PPAALLMM PPIIPPEESS Materials: ½ inch PVC pipe cut to the lengths listed below. The pipes can be marked with permanent marker or fingernail polish. The students hold the pipe in one hand and strike one of the open ends on the palm of the other hand, producing the pitch which corresponds to the length of the pipe.
Note Length *(cm)
Frequency **(Hz)
A 38.5 220 Bb (A#) 36.4 233
B 34.3 247 C 32.3 261.5
C# (Db) 30.5 277 D 28.8 293.5
D# (Eb) 27.1 311 E 25.6 329.5 F 24.1 349
F# (Gb) 22.7 370 G 21.4 392
Ab (G#) 20.2 415.5 A 19.0 440
Bb (A#) 17.9 466 B 16.9 494 C 15.9 523
C# (Db) 15.0 554 D 14.1 587
D# (Eb) 13.3 622 E 12.5 659 F 11.8 698
F# (Gb) 11.1 740 G 10.5 784
Ab (G#) 9.8 831
* Lengths of these pipes are based on an air temperature of 20° C and 0.5 in diameter. ** Frequencies taken from http://ptolemy.eecs.berkeley.edu/eecs20/week8/scale.html
Adapted and expanded from an activity presented by Hugh Henderson of Plano (Texas) Senior High School at the 2003 AP Physics Institute, Texas A&M University.
CMSE Phys
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MMUUSSIICCAALL SSCCAALLEESS
TWINKLE, TWINKLE LITTLE STAR (Nearly the same tune as the “Alphabet Song”)
Twin - kle, twin - kle lit - tle star, How I won - der what you are
Melody: F F C C D D C Bb Bb A A G G F Harmony: C C A A Bb Bb A G G F F E E C
Up a - bove the world so high, Like a dia - mond in the sky, Melody: C C Bb Bb A A G C C Bb Bb A A G Harmony: A A G G F F C A A G G F F C
Twin - kle, twin - kle lit - tle star, How I won - der what you are Melody: F F C C D D C Bb Bb A A G G F Harmony: C C A A Bb Bb A G G F F E E C
Musical scales and chart taken from http://www.geocities.com/jayatea.geo/piano.html
Tonic W Third Fourth Fifth Sixth H Tonic C D E F G A B C
C# D# F F# G# A# C C# D E F# G A B C# D D# F G G# A# C D D#
E F# G# A B C# D# E F G A A# C D E F F# G# A# B C# D# F F#
G A B C D E F# G G# A# C C# D# F G G# A B C# D E F# G# A
A# C D D# F G A A# B C# D# E F# G# A# B C D E F G A B C
CMSE Phys
3
HAPPY BIRTHDAY
Hap - py birth - day to you, hap - py birth - day to you; C C D C F E C C D C G F
Hap - py birth - day dear Ein - stein; C C C A F E D
Hap - py birth - day to you!
Bb Bb A F G F
LONDON BRIDGE
Lon - don bridge is fall - ing down, fall - ing down, fall - ing down; G A G F E F G D E F E F G
Lon - don bridge is fall - ing down, my fair la - dy. G A G F E F B D G E C
ROW, ROW, ROW YOUR BOAT
Row, row, row your boat gen - tly down the stream; C C C D E E D E F G
Mer - ri - ly, mer - ri - ly, mer - ri - ly, mer - ri - ly,
C C C G G G E E E C C C
Life is but a dream. G F E D C
WHERE IS PINKY (POINTER, ETC…) (or Are You Sleeping?)
“Where is Pin - ky? Where is Pin - key?” “Here I am! Here I am!”
C D E C C D E C E F G E F G
“How are you to - day sir?” “Ver - y well I thank you.” G A G F E C G A G F E C
Run a - way, run a - way. C G C C G C
CMSE Phys
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SSIINNGGIINNGG CCHHIIMMEESS (adapted from Taylor, Poth, & Portman (1995), Teaching Physics with TOYS,
Terrific Science Press: Middleton, Ohio. pp. 275-281)
Chimes cut from 4 five-foot pieces of ½ inch aluminum pipe. Total cost of less than $8.00 (purchased as 2 ten-foot sections, Lowe’s Home Building Store, December 2003).
Table 1: Chime Lengths Cut from pipe 1 Cut from pipe 2 Cut from pipe 3 Cut from pipe 4
Chime # Length (cm) Chime # Length (cm) Chime # Length (cm) Chime # Length (cm) 1 38.5 5 34.2 8 31.1 13 27.2 2 37.5 6 33.1 9 30.3 14 26.3 3 36.2 7 32.2 10 29.7 15 25.5 4 35.1 17 23.8 11 28.9 16 24.7 18 23.1 12 28.1 19 22.5 20 21.8
p. 276
Table 2: Chime Frequencies Chime # Note Frequency
(Hz) Chime # Note Frequency
(Hz) Chime # Note Frequency
(Hz) 1 F 175 8 C 262 15 G 392 2 F# 185 9 C# 277 16 G# 415 3 G 196 10 D 294 17 A 440 4 G# 208 11 D# 311 18 A# 466 5 A 220 12 E 330 19 B 494 6 A# 233 13 F 349 20 C 523 7 B 247 14 F# 370
p. 279
CMSE Phys
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SSIINNGGIINNGG CCHHIIMMEESS SSOONNGG SSHHEEEETT (musical scores taken from Teaching Physics with TOYS, pp 280-281)
MICHAEL ROW THE BOAT ASHORE
Mi - chael row the boat a - shore Mi - chael row the boat a - shore 10 14 17 14 17 19 17 D F# A F# A B A 10 14 10 14 15 14 D F# D F# G F# Hal - le - lu - a Hal - le - lu - a 14 17 19 17 F# A B A 10 14 15 14 D F# G F# Mi - chael row the boat a - shore Mi - chael row the boat a - shore 14 17 17 14 15 14 12 F# A A F# G F# E 10 14 14 10 12 10 9 D F# F# D E D C# Hal - le - lu - u - u - a Hal - le - lu - u - u - a 10 12 14 5 12 10 D E F# A E D 7 9 10 9 B C# D C#
HAPPY BIRTHDAY
Hap - py birth - day to you, hap - py birth - day to you; 8 8 10 8 13 12 8 8 10 8 15 13 6 8 6 6 8 8 C C D C F E C C D C G F A# C A# A# C C Hap - py birth - day dear Ag - gie; 8 8 20 17 13 12 10 17 13 8 8 6 13 8 C C C A F E D A F C C A# F C Hap - py birth - day to you! 18 18 17 13 15 13 13 13 13 8 12 8 10 10 8 8 A# A# A F G F F F F C E C D D C C
CMSE Phys
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PPllaannee MMiirrrroorr IImmaaggeess
Pre-Lab: Each group must complete and hand in their Pre-Lab Predictions before obtaining materials for this investigation. Learning Tasks: 1. Use the available resources (large plane mirror, text, computer simulation, peer counsel) to determine a plane mirror’s a) minimum length and b) vertical placement on a wall necessary for one to see a full length image when standing in front of the plane mirror.
2. Determine if/how this necessary mirror size and placement depends on an individual person’s height and distance away from the mirror.
3. Include a complete explanation of your solutions using the behavior of light to justify your answers. This explanation should include diagrams.
4. Hand in your group’s report and the Self-Evaluation Rubric.
Resources:
large plane mirrors, text, peer counsel, meter sticks, computer simulation at http://www.phy.ntnu.edu.tw/java/optics/mirror_e.html
CMSE Phys
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LLaabb RReeppoorrtt SSeellff--EEvvaalluuaattiioonn RRuubbrriicc
Report Objectives “The report contains acceptable statements describing …”
disagree unsure agree
… the minimum length of a plane mirror that is needed for a person to see one’s full length image … the mirror’s precise placement on the wall in order to see a full length image … how the mirror’s size and placement depends on the height of the viewer … how the mirror’s size and placement depends on how far the viewer is from the mirror
Report Objectives “The report contains acceptable explanations for …”
disagree unsure agree
… why the stated minimum mirror size is valid … why the stated mirror placement is valid … why the stated relationship about mirror size, placement, and viewer’s height is valid … why the stated relationship about mirror size, placement, and viewer’s distance from mirror is valid
Report Objectives “The report contains correctly drawn and properly labeled ray di agrams
that aid in the description and explanation of…” disagree unsure agree
… why the stated minimum mirror size is valid … why the stated mirror placement is valid … why the stated relationship about mirror size, placement, and viewer’s height is valid … why the stated relationship about mirror size, placement, and viewer’s distance from mirror is valid
Lab Objectives “Everyone in our lab group can now…”
disagree unsure agree
… give the minimum length of a plane mirror and its precise placement on the wall for a person of a given height to see a full length image when standing a designated distance in front of the mirror
… justify why their response to the above is valid
CMSE Phys
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PPllaannee MMiirrrroorr IImmaaggeess:: PPrree--LLaabb PPrreeddiiccttiioonnss To be given out in class.
CMSE Phys
CCuurrvveedd MMiirrrroorr RRaayy DDiiaaggrraammss Calculate the image distance and size for each case. Enter these values in the data table. Using unlined paper in a landscape orientation, draw ray diagrams in order to find the image of each 2.0 cm object. Use a compass to accurately depict the curvature of each mirror. Label the focus “F” and center of curvature “C.” Draw three rays (through or toward focus and parallel, parallel and through or away from focus, and through the center of curvature) if possible. Measure the image size and distance. Record these values in the data table and compare with the calculated. On your diagrams, classify each image as 1) REAL or VIRTUAL, 2) UPRIGHT or INVERTED, and 3) REDUCED, ENLARGED, or SAME SIZE.
Calculated Measured Lens Object Distance
Object size
Focal Length di si di si
Concave 18.0 cm 2.0 cm 6.0 cm Concave 12.0 cm 2.0 cm 6.0 cm Concave 9.0 cm 2.0 cm 6.0 cm Concave 6.0 cm 2.0 cm 6.0 cm Concave 3.0 cm 2.0 cm 6.0 cm Convex 15.0 cm 2.0 cm -5.0 cm Convex 10.0 cm 2.0 cm -5.0 cm Convex 7.0 cm 2.0 cm -5.0 cm Convex 4.0 cm 2.0 cm -5.0 cm Convex 1.0 cm 2.0 cm -5.0 cm
***Notice that the focal length of a convex mirror is negative.***
CMSE Phys
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MMeeaassuurriinngg tthhee IInnddeexx ooff RReeffrraaccttiioonn
I. Glass/Plastic/Acrylic Rectangle and/or Triangle
1. Place the rectangle/triangle on the center of your paper. Trace around it. 2. Place one pin on either side of the object, snugly up against the sides.
Rectangle: They should not be directly across from one another. Triangle: They should be directly across from one another. (Pins A and B in diagrams) 3. Look through the objects until these two pins line up in your eyesight. 4. Place another pin (C) between your eye and the two pins that are lined up in
sight. Now all three pins (A, B, and C) should seem to be lined up. 5. Place a fourth pin (D) on the other side of the object in line with the other
three. You should see all four pins lined up when you look through the object.
6. Remove the object and pins. 7. Connect the pin holes to show the path of light traveling through the
rectangle/triangle. 8. With your ruler, carefully draw a dotted line “normal” to the object’s
surface where the light ray enters the object. Draw another one where the light ray leaves the object.
9. Measure the angles of incidence and refraction where the light enters and where the light leaves the object.
10. Use Snell’s Law to calculate the index of refraction of your material. You will make this calculation for each set of angles.
11. Average the two values together. This is the material’s index of refraction. 12. Use the definition of the index of refraction to calculate the speed of light
through the material. 13. Show all calculations on your ray diagram.
CMSE Phys
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II. Circular Water Dish
1. Place the circular water dish on the center of your paper. Trace around it. Carefully fill to near the top with water.
2. Place two pins on one side of the dish, one snugly against the side slightly off the center of the dish and the other directly in line with it. (Pins A and B in diagram)
3. Look through the dish until these two pins line up in your eyesight. Place another pin on the other side of the dish snugly against the side so that all three pins that are lined up in sight. (Pin C in diagram)
4. Place a fourth pin (Pin D) behind the dish in line with the other three. You should see all four pins lined up when you look through the dish.
5. Remove the water dish and pins. 6. Connect the pin holes to show the path of light traveling through the dish. 7. With your ruler, carefully draw a dotted line “normal” to the circular surface
where the light ray enters the dish. Draw another one where the light ray leaves the dish. The normal will be a line through the center of the circular dish.
8. Measure the angles of incidence and refraction where the light enters and where the light leaves the dish.
9. Use Snell’s Law to calculate the index of refraction of the water. You will make this calculation for each set of angles.
10. Average the two values together. This is the water’s index of refraction. 11. Use the definition of the index of refraction to calculate the speed of light
through the water. 12. Show all calculations on your ray diagram.
CMSE Phys
LLeennss RRaayy DDiiaaggrraammss Calculate the image distance and size for each case. Enter these values in the data table. Using unlined paper in a landscape orientation, draw ray diagrams in order to find the image of each 2.0 cm object. Draw a double convex lens for the converging lenses and a double concave lens for the diverging. Label the focus F on each side of the lens. Draw three rays (through or toward focus and parallel, parallel and through or away from focus, and through optical center) if possible. Measure the image size and distance. Record these values in the data table and compare with the calculated. On your diagrams, classify each image as 1) REAL or VIRTUAL, 2) UPRIGHT or INVERTED, and 3) REDUCED, ENLARGED, or SAME SIZE.
Calculated Measured Lens Object Distance
Object size
Focal Length di si di si
Converging 18.0 cm 2.0 cm 6.0 cm Converging 12.0 cm 2.0 cm 6.0 cm Converging 9.0 cm 2.0 cm 6.0 cm Converging 6.0 cm 2.0 cm 6.0 cm Converging 3.0 cm 2.0 cm 6.0 cm Diverging 15.0 cm 2.0 cm -5.0 cm Diverging 10.0 cm 2.0 cm -5.0 cm Diverging 7.0 cm 2.0 cm -5.0 cm Diverging 4.0 cm 2.0 cm -5.0 cm Diverging 1.0 cm 2.0 cm -5.0 cm
***Notice that the focal length of a diverging lens is negative.***
CMSE Phys
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IImmaaggeess ffrroomm CCoonnvveerrggiinngg LLeennsseess
Learning Tasks: Complete and hand in one copy of the “PreLab Predictions” before picking up your equipment. Resources: converging lenses, candles, textbook, meter stick, computer simulation at http://www.schulphysik.de/suren/ CurvSurf/CurvSurf.html
Part I: Blocking the Front of the Lens
Use the available resources (candles, lenses, computer simulation, textbook, peer counsel) to answer the following questions:
a) What happens to the image formed by a converging lens when the top half of the front side of the lens is covered? b) What happens to the image formed by a converging lens when the bottom half of the front side of the lens is covered? c) What happens to the image formed by a converging lens when a central portion of front side of the the lens is covered? d) What happens to the image formed by a converging lens as more and more of the front side of the lens is covered?
CMSE Phys
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Part II: Blocking the Back of the Lens
Use the available resources (candles, lenses, computer simulation, textbook, peer counsel) to answer the following questions: a) What happens to the image formed by a converging lens when the top half of the back side of the lens is covered? b) What happens to the image formed by a converging lens when the bottom half of the back side of the lens is covered? c) What happens to the image formed by a converging lens when a central portion of back side of the the lens is covered? d) What happens to the image formed by a converging lens as more and more of the back side of the lens is covered? Part III: Blocking the Object
Use the available resources (candles, lenses, computer simulation, textbook, peer counsel) to answer the following questions: a) What happens to the image formed by a converging lens when the top half of the object is covered? b) What happens to the image formed by a converging lens when the bottom half of the object is covered? c) What happens to the image formed by a converging lens when a central portion of the object is covered? d) What happens to the image formed by a converging lens as more and more of the object is covered?
Develop an explanation of your answers using the behavior of light through lenses as justification.
Write and hand in a complete and organized explanation that includes diagrams to justify your responses.
CMSE Phys
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PPRREELLAABB:: IImmaaggeess ffrroomm CCoonnvveerrggiinngg LLeennsseess Draw a sketch of what you think the image on the screen would look like when various portions of the lens/object are covered. Sketch in some rays traveling from the object to the screen that would form such an image. Part I: Blocking the Front of the Lens
a) What happens to the image formed by a converging lens when the top half of the front side of the lens is covered? b) What happens to the image formed by a converging lens when the bottom half of the front side of the lens is covered? c) What happens to the image formed by a converging lens when a central portion of front side of the the lens is covered? Part II: Blocking the Back of the Lens
a) What happens to the image formed by a converging lens when the top half of the back side of the lens is covered?
CMSE Phys
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b) What happens to the image formed by a converging lens when the bottom half of the back side of the lens is covered? c) What happens to the image formed by a converging lens when a central portion of back side of the the lens is covered? Part III: Blocking the Object
a) What happens to the image formed by a converging lens when the top half of the object is covered? b) What happens to the image formed by a converging lens when the bottom half of the object is covered? c) What happens to the image formed by a converging lens when a central portion of the object is covered? .
CMSE Phys
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FFUUNN WWIITTHH LLIIGGHHTT AANNDD CCOOLLOORR
Many students are taught in art classes that the 3 PRIMARY COLORS are: _______________, _______________, and _______________.
From our own experiences with paint and/or crayons, we know that mixing different amounts of these 3 colors will produce other colors. For example,
RREEDD and YYEELLLLOOWW liquids combine to form _______________ liquid, RREEDD and BBLLUUEE liquids combine to form _______________ liquid, BBLLUUEE and YYEELLLLOOWW liquids combine to form _______________ liquid, and BBLLUUEE, YYEELLLLOOWW, and RREEDD liquids combine to form _______________ liquid.
Many do not know that mixing colors of LIGHT is quite different from mixing colors of PAINT.
To begin with, the 3 PRIMARY COLORS OF LIGHT are not red, blue, and yellow, but rather RREEDD, BBLLUUEE, and GGRREEEENN. These 3 colors, or FREQUENCIES, of light combine in different ways than do colors of paint. Believe it or not,
RREEDD and GGRREEEENN light combine to form _______________ light, RREEDD and BBLLUUEE light combine to form _______________ light, BBLLUUEE and GGRREEEENN light combine to form _______________ light, and BBLLUUEE, GGRREEEENN, and RREEDD light combine to form _______________ light.
Isaac Newton was perhaps the first person known to separate WHITE LIGHT into its component colors of ________, ________, ________, ________, ________, and ________. To do this, he used two PRISMS - one to separate light into its component colors, and the other to recombine them into white light. This method of separating light into its component colors uses the property of light known as REFRACTION.
Another way to separate any light into its component colors is through properties of light known as DIFFRACTION and INTERFERENCE. A simple SPECTROSCOPE allows light to pass through a diffraction grating in such a way that the colors making up that light become known through these two processes. Learn more about mixing light and color by viewing these simulations on the World Wide Web:
http://www.physicslessons.com/exp16b.htm http://www.physicslessons.com/exp18b.htm http://www.physicslessons.com/exp19b.htm
CMSE Phys
2
MMAAKKEE YYOOUURR OOWWNN SSPPEECCTTRROOSSCCOOPPEE
Materials:
hollow tube (paper towel roll, bamboo, toilet paper roll, etc…) , old compact disk, scissors, tape, card stock, exacto knife or razor blade, marker
Procedure:
1. Place one end of your tube on the card stock and trace around the circle. (You may want to cut “flaps” around the disk for connection purposes.)
2. Use scissors to carefully cut this circle out of the card stock. 3. NOW USE THE RAZOR BLADE OR EXACTO KNIFE TO CAREFULLY CUT A
NARROW VERTICAL SLIT IN THE CARD STOCK CIRCLE. This slit should be about 1-2 centimeters long and 1-2 millimeters wide.
4. Place this slit circle on one end of the tube and tape it into place. 5. Now place the other end of the tube on the compact disk and trace around the circle
with the marker. 6. Use scissors to carefully cut this plastic circle out of the compact disk. 7. Use tape to pull the metallic covering off the top of the compact disk until it becomes
totally transparent. 8. Place the compact disk circle on the other end of the tube and hold it into place. Do
not tape it at this time. 9. While holding the tube so that the slit is vertically oriented, look through the compact
disk end of the tube at a distant light. 10. Keep the slit circle vertical and rotate the compact disk circle until you see vertical
color bands on both the right and left sides of the vertical slit. 11. Once you have it properly oriented, tape the compact disk end in place. 12. Look at various light sources and determine the colors of light comprising each source
of light. Most incandescent and fluorescent bulbs contain all colors of the spectrum, but other gas-filled tubes contain only colors that are characteristic of the gases.
Label each color of light seen when looking at a “white” light source.
CMSE Phys
EElleeccttrriiccaall aanndd MMaaggnneettiicc PPrrooppeerrttiieess
Use the power supply, switch, wires, and light bulb to create a complete circuit that lights the bulb. Then check the electrical conductivity and magnetic attractiveness of each of your supplied materials.
Conducts Electricity? Attracted to Magnet? Object Yes No Yes No
On the back of this page, write some generalizations about:
1. conductivity and type of object 2. magnetic attraction and type of object 3. relationship, if any, between magnetic attraction and electrical conductivity
CMSE Phys
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OOhhmm’’ss LLaaww Objectives:
• determine the conductivity of various materials • set up a simple resistor circuit • measure current through a resistor using an ammeter • measure potential difference across a resistor using a voltmeter • determine resistance and verify Ohm’s Law (i.e., R = V/I is constant)
Materials:
• D-cells and cell holders, multi-meters, wire, resistors, switch
Procedure:
• Build a circuit to test the conductivity of materials in the bag. • Test these materials and complete the chart. • Draw both pictorial and schematic diagrams illustrating a circuit that includes the
Ohm’s Law materials. • Connect materials as shown in the diagrams. • Record data from the multi-meters (used as a voltmeter and an ammeter) for six
trials (using 1 - 6 cells in series) for each resistor. • For each trial, divide “Potential Difference” by “Current” to obtain the “Resistance”
for that trial (R = V/I). Average the trials for each resistor to obtain the “data table value” of resistance.
• Make a graph of “Potential Difference vs. Current” for each resistor. Include the origin (0,0) as a data point.
• Find the slope of the line that best fits your points. Enter this value as the “graph value” for the unknown resistance.
• Use the resistor color codes to determine the accepted resistance of each resistor. • Compare your experimental value with the accepted value in a conclusion paragraph.
Be sure to list sources of error in this activity.
Pictorial Diagram Schematic Diagram
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Resistor I Color Bands - - - trial I II III IV V VI VII
potential diff (V) 0 current (Amps) 0 resistance (Ω) -
Average Resistance (Ω) = Resistor II Color Bands - - -
trial I II III IV V VI VII potential diff (V) 0 current (Amps) 0 resistance (Ω) -
Average Resistance (Ω) = Resistor III Color Bands - - -
trial I II III IV V VI VII potential diff (V) 0 current (Amps) 0 resistance (Ω) -
Average Resistance (Ω) =
Analysis of Results resistor
color code accepted value, Ω
data table value, Ω
% error graph value, Ω
% error
Conclusion:
CMSE Phys
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LLiigghhtt BBuullbbss iinn SSeerriieess,, PPaarraalllleell,, aanndd CCoommbbiinnaattiioonn
Each group must hand in their pre-lab predictions before obtaining the materials for this investigation. Learning Tasks:
1. Use the available resources (bulbs and circuit items, web-based circuit simulation, text, peer counsel) to determine what happens to the brightness of identical light bulbs in a dc circuit as more and more bulbs are a) added in series and b) added in parallel.
2. Develop a thorough explanation of why this occurs.
3. Use these same resources to develop an explanation of how one can determine the relative brightness of multiple bulbs when they
are connected in combination circuits.
4. Hand in a complete explanation of your findings, containing multiple examples comparing the brightness of the bulbs in each type of circuit (series, parallel, and combination). Your explanation should include a method of how one may look at a schematic diagram of a combination circuit and be able to a) list the bulbs in order of increasing or decreasing brightness and b) tell which bulbs would be equally bright. Illustrate your method with two or more examples containing at least six bulbs in each of varying brightness.
Resources: bulbs, wire, D cells, cell holders, multi-meters, textbook, peer counsel, computer simulation of a circuit found at http://www.physicslessons.com/exp22b.htm
CMSE Phys
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LLiigghhtt BBuullbbss iinn SSeerriieess,, PPaarraalllleell,, aanndd CCoommbbiinnaattiioonn:: PPrree--LLaabb PPrreeddiiccttiioonnss
CMSE Physics
EElleeccttrriiccaall EEnneerrggyy CCoossttss
The kilowatt-hour (kWh) is the basic unit of electrical energy used in determining one’s electrical utility costs. Since POWER = WORK /TIME (P = W/t), the kWh is actually a unit of WORK (W = P x T), or ENERGY, and is not a unit of power, as it is commonly believed and referred to. Therefore, one kWh (“kilo-Watt hour”) is equal to the total energy “consumed” (or “transferred”) by an electrical device with a power rating of one kilowatt during each hour of use. The electrical utility company will typically charge a home a set monthly rate for service plus an additional cost for each kWh used during the month. These rates vary by location, but generally fall between 5 and 10 cents ($0.05 - $0.10) per kWh. To find the total cost for using an electrical appliance in your home for one month, first find the number of kWh of energy used by multiplying its power (in kilowatts) by the total amount of time (in hours) used during the month. You may have to do some unit conversions to obtain this total. Then multiply this value by the cost per kWh to find the total cost. Procedure: I. Find the total monthly cost for using these devices, given the estimated times of usage. Assume a 30 day month and $0.075 per kWh.
Appliance Power Usage Total Time Total kWh Cost night light 5 W 9 hr/night porch light 60 W 12 hr/night
radio 20 W 4 hr/day microwave 750 W 30 min/day television 88 W 6 hr/day central air 8200 W 15 min/hr
clock 10 W all day hair dryer 1800 W 5 min/day
iron 1200 W 4 hr/week ceiling fan 12 W 8 hr/day
II. Make a chart similar to the one above and find out how much your family pays to use electrical devices each month by finding 15 (fifteen) examples in your own home. Be sure to make a realistic estimate of the actual amounts of time they are in use. Your 15 examples may include a maximum of 5 light fixtures or bulbs. Believe it or not, several students in the past have copied others work or just made up something to turn in and have missed the benefit of this assignment. Therefore, you must have this paper signed by a parent or guardian before handing it in to verify your own original work. “I verify that my child completed this assignment by finding actual examples in our home and doing his/her unique work.” Signature: _________________________________________ Date: ______________
CMSE Phys
EElleeccttrroommaaggnneett SSttrreennggtthh
Determine how the potential difference (voltage) applied to an electromagnet (with a fixed number of turns) affects its strength by comparing the applied potential difference to the electromagnet’s attraction to a force scale.
# Turns of Wire # “D” Cells Electric Potential Difference, Volts Strength, N
1 2 3 4 5 6
Make a graph of Electromagnet Strength vs. Potential Difference. Include the origin as one of your data points. What does the shape of this graph indicate about the relationship between an electromagnet’s strength and its applied potential difference?
Now use a fixed potential difference and vary the number of turns of wire to see how the number of turns of wire affects the strength of the electromagnet.
# “D” Cells Electric Potential Difference, Volts # Turns of Wire Strength, N
4 4 4 4 4 4
Make a graph of Electromagnet Strength vs. # Turns of Wire. Include the origin as one of your data points. What does the shape of this graph indicate about the relationship between an electromagnet’s strength and its number of turns of wire? What would you need to do to make a really strong electromagnet?
CMSE Phys
1
FFUUNN WWIITTHH EELLEECCTTRRIICCIITTYY AANNDD MMAAGGNNEETTIISSMM
When a complete circuit is connected to a power supply, electric current, made up of extremely tiny particles (or waves, but that is another very long story) called electrons, flows through the wire and other circuit elements and transfer electric potential energy. This energy may be used to produce light, generate heat, and/or cause motion that we use in many products every day.
Connect the circuit, throw the switch, and make the light bulb glow.
Over 100 years ago, scientists discovered that when electric current flows through a wire, a magnetic field is produced around the wire.
Open the switch, place a compass under the wire so that the wire lines up with the compass needle, and then close the switch. What do you notice?
The deflection of the compass needle indicates the presence of a magnetic field around the current bearing wire. This knowledge soon led to practical applications of this phenomenon, including the construction of strong electromagnets that can be turned on and of at will, motors for converting electric energy into mechanical energy, and generators for converting mechanical energy into electric energy.
A simple electric motor can be constructed in a very short time using common and inexpensive materials. To do this, a current-bearing loop of wire is constructed in a manner that causes the magnetic field from a nearby ceramic magnet to interact with the magnetic field surrounding the current-bearing wire loop and cause the loop of wire to spin.
MMAAKKEE YYOOUURR OOWWNN DDCC EELLEECCTTRRIICC MMOOTTOORR
Materials: dry cell, small disk magnet, rubber band, 2 large paperclips, about 2 feet thin wire, nail, test tube or thick marker, scissors
Procedure:
1. Take the 2 foot piece of thin wire and wrap it around the test tube (or thick marker). The number of wraps depends on the gauge (“thinkness”) of the wire.
2. “Tie” the ends of the wire through the loops so that the loop of wire will remain in place when you let go.
CMSE Phys
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3. Bend the paper clips in order to form loops on their ends, which will be used for holding the wire loop.
4. Secure these to the dry cell with the rubber band.
5. Place the magnet on the dry cell and place the wire loop in its holders. Observe what happens.
6. Disappointed that nothing happened? The reason is that the wire is insulated with paint, which must be scraped off. This is the trickiest part. Whether or not the ends of the wire loop are scraped correctly will determine the
success of your motor.
7. Hold the wire loop vertically between your thumb and index finger of one hand near the edge of the table (desk) so that the wire end lies on the table.
8. Use the other hand and the scissors to scrape the insulation off the top half of the wire.
9. Turn the wire loop around and scrape the top half of the other end.
10. Place the wire loop into its holders and move the loop so that it lies just above the
magnet. The motor should now begin spinning. If not, you may need to give it a little push to get it going.
Other instructions and pictures of electric motors made in similar ways may be found on the World Wide Web at:
http://fly.hiwaay.net/~palmer/motor.html http://www.exploratorium.edu/snacks/stripped_down_motor.html
http://www.scitoys.com/scitoys/scitoys/electro/electro.html#motor
CMSE Phys
1
SSiimmuullaatteedd RRaaddiiooaaccttiivvee DDeeccaayy -- DDiiccee Instructions:
1. Complete the “Theoretical Decay” table entries by assuming that exactly 1/6 of all nuclei initially present decay each time period. Do this by taking 1/6 of the “initial number present” and round to the nearest whole number. Enter this number as the “number decayed.” 2. Subtract this value from the “initial number present” and record as the “number
remaining.” 3. Repeat this process until the chart is complete or fewer than ten nuclei remain
undecayed. 4. Make a graph of “Number of Radioactive Nuclei Present vs Time – Theoretical.” Draw
a smooth curve through your data points.
Now repeat this process using the dice to represent the unstable nuclei:
5. Begin with 300 dice. Toss the dice and remove each one showing the number ____________. The number you remove will be the “number decayed.” 6. Subtract the “number decayed” from the “initial number present” to obtain the “number remaining.” 7. Toss the remaining dice and again remove all those that “decay.” 8. Repeat this process until the chart is complete or fewer than ten dice remain. 9. Make a graph of “Number of Radioactive Nuclei Present vs Time – Experimental.”
Draw a smooth curve through your data points.
Discussion:
a. Compare your “Theoretical Decay” chart and graph with the “Experimental Decay” chart and graph.
b. Use the graph to estimate the amount of time necessary for your experimental number to go from 300 to 150 _____, 250 to 125 _____, 200 to 100 _____, 150 to 75 _____, and 100 to 50 _____.
c. Based on your answers above, what is the approximate half-life of your “radioactive” sample?
Extension: Repeat this decay simulation using more than one digit to represent a decayed nucleus and compare with the previous results.
CMSE Phys
2
DDaattaa TTaabbllee -- DDiiccee Dice: Theoretical Decay Dice: Experimental Decay
Elapsed Time
Initial Number Present
Number Decayed
Number Remaining
Initial Number Present
Number Decayed
Number Remaining
0 300 300 1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
CMSE Phys
3
SSiimmuullaatteedd RRaaddiiooaaccttiivvee DDeeccaayy -- RRaannddoomm NNuummbbeerrss Instructions:
1. Complete the “Theoretical Decay” table entries by assuming that exactly 1/10 of all nuclei initially present decay each time period. Do this by taking 1/10 of the “initial number present” and round to the nearest whole number. Enter this number as the “number decayed.”
2. Subtract this value from the “initial number present” and record as the “number remaining.”
3. Repeat this process until the chart is complete or fewer than ten nuclei remain undecayed.
4. Make a graph of “Number of Radioactive Nuclei Present vs Time – Theoretical.” Draw a smooth curve through your data points.
Now repeat this process using the dice to represent the unstable nuclei:
5. Begin with 500 random digits. Choose the digit _____ and mark through each one of these. The number you mark out will be the “number decayed.”
6. Subtract the “number decayed” from the “initial number present” to obtain the “number remaining.”
7. Block out the remaining number of digits and again mark through all those that “decay.” 8. Repeat this process until the chart is complete or fewer than ten digits remain. 9. Make a graph of “Number of Radioactive Nuclei Present vs Time – Experimental.”
Draw a smooth curve through your data points.
Discussion:
a. Compare your “Theoretical Decay” chart and graph with the “Experimental Decay” chart and graph.
b. Use the graph to estimate the amount of time necessary for your experimental number to go from 500 to 250 _____, 400 to 200 _____, 300 to 150 _____, 200 to 100 _____, and 100 to 50 _____.
c. Based on your answers above, what is the approximate half-life of your “radioactive” sample? Extension: Repeat this decay simulation using more than one digit to represent a decayed nucleus and compare with the previous results.
CMSE Phys
4
DDaattaa TTaabbllee -- RRaannddoomm NNuummbbeerrss Random Numbers:
Theoretical Decay Random Numbers:
Experimental Decay
Elapsed Time
Initial Number Present
Number Decayed
Number Remaining
Initial Number Present
Number Decayed
Number Remaining
0 500 500 1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
CMSE Phys
5
RRaannddoomm DDiiggiittss CChhaarrtt http://www.rand.org/publications/classics/randomdigits/randomdata.html
00000 10097 32533 76520 13586 34673 54876 80959 09117 39292 74945 00001 37542 04805 64894 74296 24805 24037 20636 10402 00822 91665 00002 08422 68953 19645 09303 23209 02560 15953 34764 35080 33606 00003 99019 02529 09376 70715 38311 31165 88676 74397 04436 27659 00004 12807 99970 80157 36147 64032 36653 98951 16877 12171 76833 00005 66065 74717 34072 76850 36697 36170 65813 39885 11199 29170 00006 31060 10805 45571 82406 35303 42614 86799 07439 23403 09732 00007 85269 77602 02051 65692 68665 74818 73053 85247 18623 88579 00008 63573 32135 05325 47048 90553 57548 28468 28709 83491 25624 00009 73796 45753 03529 64778 35808 34282 60935 20344 35273 88435 00010 98520 17767 14905 68607 22109 40558 60970 93433 50500 73998 00011 11805 05431 39808 27732 50725 68248 29405 24201 52775 67851 00012 83452 99634 06288 98083 13746 70078 18475 40610 68711 77817 00013 88685 40200 86507 58401 36766 67951 90364 76493 29609 11062 00014 99594 67348 87517 64969 91826 08928 93785 61368 23478 34113 00015 65481 17674 17468 50950 58047 76974 73039 57186 40218 16544 00016 80124 35635 17727 08015 45318 22374 21115 78253 14385 53763 00017 74350 99817 77402 77214 43236 00210 45521 64237 96286 02655 00018 69916 26803 66252 29148 36936 87203 76621 13990 94400 56418 00019 09893 20505 14225 68514 46427 56788 96297 78822 54382 14598 00020 91499 14523 68479 27686 46162 83554 94750 89923 37089 20048 00021 80336 94598 26940 36858 70297 34135 53140 33340 42050 82341 00022 44104 81949 85157 47954 32979 26575 57600 40881 22222 06413 00023 12550 73742 11100 02040 12860 74697 96644 89439 28707 25815 00024 63606 49329 16505 34484 40219 52563 43651 77082 07207 31790 00025 61196 90446 26457 47774 51924 33729 65394 59593 42582 60527 00026 15474 45266 95270 79953 59367 83848 82396 10118 33211 59466 00027 94557 28573 67897 54387 54622 44431 91190 42592 92927 45973 00028 42481 16213 97344 08721 16868 48767 03071 12059 25701 46670 00029 23523 78317 73208 89837 68935 91416 26252 29663 05522 82562 00030 04493 52494 75246 33824 45862 51025 61962 79335 65337 12472 00031 00549 97654 64051 88159 96119 63896 54692 82391 23287 29529 00032 35963 15307 26898 09354 33351 35462 77974 50024 90103 39333 00033 59808 08391 45427 26842 83609 49700 13021 24892 78565 20106 00034 46058 85236 01390 92286 77281 44077 93910 83647 70617 42941 00035 32179 00597 87379 25241 05567 07007 86743 17157 85394 11838 00036 69234 61406 20117 45204 15956 60000 18743 92423 97118 96338 00037 19565 41430 01758 75379 40419 21585 66674 36806 84962 85207 00038 45155 14938 19476 07246 43667 94543 59047 90033 20826 69541 00039 94864 31994 36168 10851 34888 81553 01540 35456 05014 51176 00040 98086 24826 45240 28404 44999 08896 39094 73407 35441 31880 00041 33185 16232 41941 50949 89435 48581 88695 41994 37548 73043 00042 80951 00406 96382 70774 20151 23387 25016 25298 94624 61171 00043 79752 49140 71961 28296 69861 02591 74852 20539 00387 59579 00044 18633 32537 98145 06571 31010 24674 05455 61427 77938 91936 00045 74029 43902 77557 32270 97790 17119 52527 58021 80814 51748 00046 54178 45611 80993 37143 05335 12969 56127 19255 36040 90324 00047 11664 49883 52079 84827 59381 71539 09973 33440 88461 23356 00048 48324 77928 31249 64710 02295 36870 32307 57546 15020 09994 00049 69074 94138 87637 91976 35584 04401 10518 21615 01848 76938 00050 09188 20097 32825 39527 04220 86304 83389 87374 64278 58044
CMSE Phys
6
00051 90045 85497 51981 50654 94938 81997 91870 76150 68476 64659 00052 73189 50207 47677 26269 62290 64464 27124 67018 41361 82760 00053 75768 76490 20971 87749 90429 12272 95375 05871 93823 43178 00054 54016 44056 66281 31003 00682 27398 20714 53295 07706 17813 00055 08358 69910 78542 42785 13661 58873 04618 97553 31223 08420 00056 28306 03264 81333 10591 40510 07893 32604 60475 94119 01840 00057 53840 86233 81594 13628 51215 90290 28466 68795 77762 20791 00058 91757 53741 61613 62269 50263 90212 55781 76514 83483 47055 00059 89415 92694 00397 58391 12607 17646 48949 72306 94541 37408 00060 77513 03820 86864 29901 68414 82774 51908 13980 72893 55507 00061 19502 37174 69979 20288 55210 29773 74287 75251 65344 67415 00062 21818 59313 93278 81757 05686 73156 07082 85046 31853 38452 00063 51474 66499 68107 23621 94049 91345 42836 09191 08007 45449 00064 99559 68331 62535 24170 69777 12830 74819 78142 43860 72834 00065 33713 48007 93584 72869 51926 64721 58303 29822 93174 93972 00066 85274 86893 11303 22970 28834 34137 73515 90400 71148 43643 00067 84133 89640 44035 52166 73852 70091 61222 60561 62327 18423 00068 56732 16234 17395 96131 10123 91622 85496 57560 81604 18880 00069 65138 56806 87648 85261 34313 65861 45875 21069 85644 47277 00070 38001 02176 81719 11711 71602 92937 74219 64049 65584 49698 00071 37402 96397 01304 77586 56271 10086 47324 62605 40030 37438 00072 97125 40348 87083 31417 21815 39250 75237 62047 15501 29578 00073 21826 41134 47143 34072 64638 85902 49139 06441 03856 54552 00074 73135 42742 95719 09035 85794 74296 08789 88156 64691 19202 00075 07638 77929 03061 18072 96207 44156 23821 99538 04713 66994 00076 60528 83441 07954 19814 59175 20695 05533 52139 61212 06455 00077 83596 35655 06958 92983 05128 09719 77433 53783 92301 50498 00078 10850 62746 99599 10507 13499 06319 53075 71839 06410 19362 00079 39820 98952 43622 63147 64421 80814 43800 09351 31024 73167 00080 59580 06478 75569 78800 88835 54486 23768 06156 04111 08408 00081 38508 07341 23793 48763 90822 97022 17719 04207 95954 49953 00082 30692 70668 94688 16127 56196 80091 82067 63400 05462 69200 00083 65443 95659 18288 27437 49632 24041 08337 65676 96299 90836 00084 27267 50264 13192 72294 07477 44606 17985 48911 97341 30358 00085 91307 06991 19072 24210 36699 53728 28825 35793 28976 66252 00086 68434 94688 84473 13622 62126 98408 12843 82590 09815 93146 00087 48908 15877 54745 24591 35700 04754 83824 52692 54130 55160 00088 06913 45197 42672 78601 11883 09528 63011 98901 14974 40344 00089 10455 16019 14210 33712 91342 37821 88325 80851 43667 70883 00090 12883 97343 65027 61184 04285 01392 17974 15077 90712 26769 00091 21778 30976 38807 36961 31649 42096 63281 02023 08816 47449 00092 19523 59515 65122 59659 86283 68258 69572 13798 16435 91529 00093 67245 52670 35583 16563 79246 86686 76463 34222 26655 90802 00094 60584 47377 07500 37992 45134 26529 26760 83637 41326 44344 00095 53853 41377 36066 94850 58838 73859 49364 73331 96240 43642 00096 24637 38736 74384 89342 52623 07992 12369 18601 03742 83873 00097 83080 12451 38992 22815 07759 51777 97377 27585 51972 37867 00098 16444 24334 36151 99073 27493 70939 85130 32552 54846 54759 00099 60790 18157 57178 65762 11161 78576 45819 52979 65130 04860 00100 03991 10461 93716 16894 66083 24653 84609 58232 88618 19161
CMSE Phys
7
CMSE Phys
8