forces and motion - moore public schools · exploration c 1. obtain a beaker, index card/playing...

Name ________________________________ Date __________________ Hour _____

8th

Grade Science Forces & Motion

Forces and Motion

Exploration A

1. Obtain two billiard balls, a pool stick, a strip of felt, and a coin.

2. A 20 cm diameter circle has been drawn on one end of the felt.

3. Place one billiard ball in the center of the circle.

4. Place the coin on top of this ball.

5. Place the other billiard ball at the other end of the felt. This will represent the cue

ball in billiards.

6. The object of this “game” is to try to knock the coin outside the circle.

7. Shoot the cue ball at the billiard ball in the center of the circle.

8. What observations can you make?

Exploration B

1. Obtain three to four wooden blocks and a piece of paper.

2. Stack the blocks in a vertical column on top of the piece of paper.

3. Remove the paper from underneath the blocks with a rapid motion.


Exploration C

1. Obtain a beaker, index card/playing card, and a coin.

2. Place the card evenly over the opening of the beaker.

3. Set the coin in the middle of the card.

4. Flick the card with your index or middle finger in a horizontal and quick motion.


Exploration D

1. Trace around the mouth of a baby food jar on an index card. Cut out the circle

and tape its edge so some thread about as long as notebook paper.

2. Set up this obstacle based upon the three cases pictured below. In each case, yank

on the thread as quickly as possible and observe what happens. For the third case,

simply flick the circle with your finger.

Name ________________________________ Date __________________ Hour _____

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3. What happens in each scenario?

4. Which case seemed to be the most tricky or difficult?

Exploration E

1. Cut off 4 strips of index card exactly 3 spaces wide. Overlap them, like shingles

on a roof and in the same direction, about the width of your little finger, and

secure with tape.

2. Overlap the ends, keeping the tape to the outside of the circle. Tape again to form

a closed hoop. No inside tape is needed.

3. Balance the hoop over an Erlenmeyer flask. Crunch together a small wad of

aluminum foil to balance on top.

4. Drop the foil into the flask by touching only the hoop with only one finger.

5. Explain the best way for this trick to work.

Exploration F

The above activities involved some type of motion. But why does each object

move as it does? What causes an object to start moving, stop moving, or change

direction? The answer is a force. In each of the above activities, a force is applied to an

object. In science, the word force has a simple and specific meaning. A force is a push

or a pull. You exert a force on a pen when you write, on a book when you lift it, and on a

ball when you throw it. You exert a force on a pebble when you skim it across a pond, on

a wagon when you pull it, and on a nail when you hammer it into a piece of wood.

Forces are described two ways. They are described not only by how strong they are, but

also by the direction in which they act. The following exploration will show you how

forces act together at times and against each other at times.

1. You will be split up into two teams in order to play tug-of-war.

2. The two teams will pull on opposite ends of a rope until your teacher signals you

to stop.

3. Unlike many tug-of-wars, this is not a competition, but a scientific experiment.

4. Some rules to keep in mind are: Don’t tie the rope around yourself and don’t

wrap the rope around your hand/wrist.

5. What observations can you make from the first tug-of-war competition? Diagram

the forces below.

6. What observations can you make from the second tug-of-war competition?

Diagram the forces below.

Name ________________________________ Date __________________ Hour _____

8th


Exploration G

1. A student volunteer will be chosen to sit on a hovercraft with the leaf blower off.

2. Diagram and label the forces acting on the hovercraft.

3. Describe the motion of the hovercraft.

4. Push the hovercraft with the leaf blower off.

5. What is motion of the hovercraft?

6. What force causes the hovercraft to act this way?

7. Sit on the hovercraft and turn the leaf blower on.

8. What is the motion of the hovercraft when the leaf blower is turned on and the

skirt is filled?

9. What is the function of the skirt?

10. Diagram and label the forces acting on the hovercraft.

11. Push the hovercraft and release it.

12. Describe the motion of the hovercraft is it is being pushed.

13. Diagram and label the forces on the hovercraft as it is being pushed.

14. Describe the motion of the hovercraft after it has been released.

15. Diagram and label the forces acting on the hovercraft after it has been released.

Name ________________________________ Date __________________ Hour _____

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Exploration G Discussion Notes

Idea Questions – Use complete sentences to answer the following questions.

1. What is the motion of the hovercraft when the vacuum is turned on after the skirt

is filled?

2. What are the forces acting on the hovercraft when the vacuum is turned on?

3. Are the forces balanced or unbalanced? Explain your answer.

4. Describe the motion of the hovercraft as it is being pushed.

5. What are the forces acting on the hovercraft as it is being pushed?

Name ________________________________ Date __________________ Hour _____

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7. Describe the motion of the hovercraft after it has been released?

8. What are the forces acting on the hovercraft after it is released?


10. What happens to the hovercraft when the forces are balanced?

11. What happens to the hovercraft when the forces are unbalanced?

12. Write a general statement that describes how balanced and unbalanced forces

affect the motion of the hovercraft.

13. What is this relationship called?

Name ________________________________ Date __________________ Hour _____

8th


Exploration Discussion Questions – Answer the following questions using complete

sentences using Newton’s first law of inertia to explain the observations we made in

explorations A – E.

1. Exploration A – Billiard Game – Why did the quarter fall in the middle of the

large circle when you struck the tennis ball with a moderate to hard force?

2. Exploration A – Billiard Game – Explain why the quarter fell out of the large

circle when you struck the tennis ball with a small force.

3. Exploration B – Wood Blocks Game – Why did the blocks of wood remain

upright when you pull on the paper with a very quick horizontal/downward force?

4. Exploration C – Playing Card & Penny Game – Why does the penny fall into the

beaker when you flick the playing card?

5. Exploration D – Round Disc & Penny Games – Why does the penny remain on

the Lincoln Log and/or your finger when you apply a force upon the disc?

6. Exploration E – Round Hoop & Foil Ball Game – Why does the foil ball fall into

the flask when you apply a force upon the round hoop?

Name ________________________________ Date __________________ Hour _____

8th


Expansion A

1. A 10 meter distance has been measured off and tape placed every 2 meters.

2. Have a student stand at each tape mark (except zero) with a stop watch.

3. Push the hovercraft and release it at the zero tape mark.

4. Each student should start their stop watch when the hovercraft reaches the zero

tape mark and stop it when it reaches their tape mark.

5. Record the times for each stop watch in the table below.

6. Repeat steps 3 through 5 two more times and then average the data for each mark.

Data Table 1 - ____________________________________________________

Trial/Distance 2 meters 4 meters 6 meters 8 meters 10 meters

1

2

3

Average

7. Make a line graph of the average data using the graph below.

8. Describe the shape of your graph.

9. What happens to the time as the distance increases?

10. What is this relationship of distance and time called?

Name ________________________________ Date __________________ Hour _____

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11. How do you calculate this relationship?

12. What SI units are used to express this relationship?

Expansion B - Word Problems: Show your work on the following problems.

1. A cyclist races 200 meters in 20 seconds. What is the speed of the cyclist?

2. What is the speed of a car that travels 1000 feet in 8 seconds?

3. A roadrunner is traveling at a speed of 65 cm/sec. How many meters will the

roadrunner travel in one hour?

4. Light travels at a speed of 300,000,000 meters/sec. The sun is 149,000,000,000

meters from Earth. How long does it take light to reach the Earth?

5. Intravenous fluids (IV’s) are often given to a patient at the rate of 125 mL per

hour. How long will it take to give a patient 1000 mL of IV fluid?

Name ________________________________ Date __________________ Hour _____

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The graph below shows the relationship between distance and time for three speedboats.

6. Which speedboat is traveling the fastest? Explain your answer.

Expansion C – Making and Understanding Speed Graphs

1. Make a general graph showing a car speeding up over time. Time will be on the

x-axis and speed on the y-axis.

2. Make a general graph showing a car standing still over time. Time will be on the

x-axis and distance on the y-axis.

3. Make a general graph showing a car slowing down over time. Time will be on

the x-axis and speed on the y-axis.

Name ________________________________ Date __________________ Hour _____

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4. Make a general graph showing a car moving at a constant speed over time. Time

will be on the x-axis and distance on the y-axis.

Expansion D

Materials:

1. Obtain a rubber band, launcher, three projectile objects, stop watch, meter stick,

and tape.

2. Place a piece of tape on the floor and mark it zero.

3. From the zero mark, measure off a 3 meter distance and mark it with tape.

4. Stretch the rubber band and place it on the two screws so it is at the top of the

screws.

5. Place the front edge of the launcher on the zero mark.

6. Have the timer with the stop watch stand at the three meter mark.

7. Using one of the projectile objects, pull the rubber band back so the projectile

object is at the mark labeled “B” on the launcher.

8. The timer should start the stop watch when the projectile is released and stop it

when the projectile reaches the three meter mark. When the timer is ready let the

projectile go at the signal.

9. Record your data in table two making sure you use the correct space.

10. Repeat steps five through nine for each of the other two projectile objects and

average the class data.

Data Table 2 - _______________________________________________________

Unit is

seconds

Group

1

Group

2

Group

3

Group

4

Group

5

Group

6

Group

7

Group

8

Class

Average

Projectile

Object 1

Projectile

Object 2

Projectile

Object 3

11. What is the independent variable in this experiment?

12. What is the dependent variable in this experiment?

Name ________________________________ Date __________________ Hour _____

8th


13. What variables were controlled in this experiment?

14. Measure the mass of the projectile objects and record it in data table 3.

15. Calculate the speed for each projectile object and record it in data table 3.

Data Table 3 - _________________________________________________________

Mass (g) Distance (m) Time (sec) Speed (m/s)

Projectile

Object 1

Projectile

Object 2

Projectile

Object 3

16. Create a bar graph comparing the masses of the objects in graph 2.

17. Create a bar graph comparing the speed of the objects in graph 3.

Graph 2 - _________________________ Graph 3 - _________________________

18. What variable does speed represent in this experiment?

19. Record the formula used to calculate the variable represented in question 18.

20. What happened to the speed as the mass of the projectile increased?

21. What purpose do the rubber bands serve in this experiment?

Name ________________________________ Date __________________ Hour _____

8th


22. What happened to the force in the experiment?

23. How are all three of the variables in this experiment related?

24. What law of physics does your data support?

Expansion E

1. Obtain 3 rubber bands, 1 ball, a spring scale, launcher, stop watch, meter stick,

and tape.

2. Place a piece of tape on the floor and mark it zero.

3. From the zero mark, measure off a 5 meter distance and mark it with tape.

4. Stretch one rubber and place it on the two screws so it is at the top of the screws.

5. Place the front edge of the launcher on the zero mark.

6. Have the timer with the stop watch stand at the 5 meter mark.

7. Using the projectile object, pull the rubber band back so the ball is at the mark

labeled “C” on the launcher.

8. The timer should start the stop watch when the ball is released and stop it when

the ball reaches the 5 meter mark. When the timer is ready, let the ball go at the

signal.

9. Record you data in table 4 under your group number.

10. Add another rubber band to the launcher (two total) and repeat steps 5 through 9).

11. Add a third rubber band to the launcher (three total) and repeat steps 5 through 9).

Then, average the class data.

Data Table 4 - ______________________________________________________

Units in

seconds

Group

1

Group

2

Group

3

Group

4

Group

5

Group

6

Group

7

Group

8

Class

Average

1

Rubber

Band

2

Rubber

Bands

3

Rubber

Bands

12. What is the independent variable in this experiment?

13. What is the dependent variable in this experiment?

Name ________________________________ Date __________________ Hour _____

8th


14. What variables are controlled in this experiment?

15. Put on rubber band on the launcher and hook the spring scale to the center of the

rubber band.

16. Pull back on the spring scale until the rubber band reaches mark “C” on the

launcher.

17. Read the number of newtons on the spring scale and record it in table 5.

18. Place a second rubber band on the launcher and repeat steps 16 and 17.

19. Add a third rubber band on the launcher and repeat steps 16 and 17.

20. Calculate the speed for each trial using the class average and record it in table 5.

Data Table 5 - _________________________________________________________

Force on Ball

(N)

Distance (m) Time (sec) Speed (m/s)

One Rubber

Band

Two Rubber

Bands

Three Rubber

Bands

21. Create a bar graph comparing the force on the ball for each trial in Graph 4.

22. Create a bar graph comparing the speed of the ball for each trial in Graph 5.

Graph 4 - _________________________ Graph 5 - __________________________

23. What variable does speed represent in this experiment?

Name ________________________________ Date __________________ Hour _____

8th


24. What happened to the speed as the force of the ball increased?

25. What purpose do the rubber bands serve in this experiment?

26. What happened to the force in this experiment?

27. How are all three of the variables in this experiment related?

28. What law of physics does your data support?

Expansion F

1. Obtain the following materials: Cookie sheet, toilet tissue tube, tape, 1 sheet of

white typing paper, 1 marble, small cup or bowl, red food coloring, ruler, and

latex gloves.

2. Place the toilet paper tube on one corner of the cookie sheet so that one end rests

on the rim of a short side of the pan. Tape only the end of the tube on the rim of

the cookie sheet. Do not tape both ends.

3. Place a piece of typing paper on the pan so that the corner is under the loose end

of the tube. See the figure below for guidance.

4. Prop up the long end of the pan by placing a book under one side of the pan. The

pan should be propped up about 2.5 cm.

5. Fill the cup about one-quarter full with water. Add ten drops of food coloring and

stir.

6. One member of the group will need to put on the latex gloves and immerse the

marble into the colored water.

7. Place the marble in the inclined end of the tube and observe the path the marble

leaves on the paper.

Name ________________________________ Date __________________ Hour _____

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8. Draw a box below.

9. Draw the path the marble traveled.

10. Show the direction or directions the marble traveled by drawing straight-line

arrows in the box.

11. What shape/form does the marble’s path appear to take?

12. What is the name of the force that changes the direction of the marble?

13. What term is used to describe the motion of a moving object that does not have a

force acting upon it?

14. How would these two factors influence the motion of a planets orbit?

15. Why do you think the planets revolve around the Sun and not the other planets in

the solar system?

16. Then based upon your answer to question fifteen above, why do you think our

moon revolves around the Earth and not around the Sun?

Name ________________________________ Date __________________ Hour _____

8th


Expansion G - Cornell Notetaking – Two Column Notetaking

Before Reading: Obtain a sheet of notebook paper and divide into two parts by

drawing a vertical line about 2 to 3 inches from the left edge of the paper. During and

After Reading: As you read each subsection, list the subtitles in the reading on the left

side of the line on your sheet of paper as you read. Jot the important details to the right

side of each subtitle as you read about each subtitle. Read and take notes over only those

subsections below. Note the number of notes required to earn full points for this

expansion.

After Reading: Your teacher will share a powerpoint presentation with you that

will review the material you read. Compare your notes with those of your teacher. Add

important points you missed and take out points you feel do not have much importance.

Chapter One: Pages 6 to 34 – (39 Notes)

1. Position describes the location of an object – 1

2. Describing a Position – 1

3. Motion is a change in position – 2

4. Describing Motion – 2

5. Relative Motion – 2

6. Position can change at different rates – 2

7. Calculating Speed – 4

8. Distance-Time Graphs – 6

9. Velocity includes speed and direction – 1

10. Velocity – 2

11. Velocity Versus Speed – 1

12. Speed and direction can change with time – 5

13. Acceleration can be calculated from velocity and time – 3

14. Calculating Acceleration – 3

15. Velocity – Time Graphs – 4

Chapter Two: Pages 38 to 70 – (27 Notes)

16. A force is a push or a pull – 2

17. Types of Forces – 3

18. Size and Direction of Forces – 2

19. Balanced and Unbalanced Forces – 4

20. Forces on Moving Objects – 3

21. Newton’s First Law – 1

22. Inertia – 3

23. Newton’s second law relates force, mass, and acceleration – 1

24. Newton’s Second Law – 2

25. Force Equals Mass Times Acceleration – 3

26. Mass and Acceleration – 1

27. Forces can change the direction of motion – 2

Name ________________________________ Date __________________ Hour _____

8th


Chapter Three: Pages 74 to 104 – (14 Notes)

28. Masses attract each other – 2

29. The Force of Gravity – 1

30. The Mass of the Objects – 1

31. The Distance Between the Objects – 1

32. Weight and Mass – 5

33. Gravity keeps objects in orbit – 1

34. Friction occurs when surfaces slide against each other – 1

35. Types of Surfaces – 1

36. Force Pressing the Surfaces Together – 1

Expansion H – Videos

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