1.3 measurement no new opener - friday, august 26, 2011 - record in openers as such... *instead have...
TRANSCRIPT
1.3 Measurement
NO NEW OPENER - FRIDAY, AUGUST 26, 2011 - RECORD in openers as such...*Instead have out your notes packet and homework worksheet on desk completed.
CW: Notes Scientific Notation... (Section III under measurement...) class whole...CW: Finish all labs and turn in lab reports before you leave school today....*Helicopter Lab*Check Lab*Golf/Ramp lab (Pre-AP required) - Reg. only for those who had started previously and are caught up with other notes...CW: Finish any previous notes that you didn’t complete from this week after labs. The paragraph in last part of notes stays stapled with notes packet.HW: Scientific Notation Problems due on TUESDAY next week...
Pre-AP: Start on Scientific Notation Lab if time and/or work on study guide questions...
Pre-AP - put “Writing in Science Question” in box if you had failed to complete this previously from pg. 11... Last chance to add points back into your grade...
1.3 Measurement
How old are you? How tall are you? The answers to these questions are measurements. Measurements are important in both science and everyday life. It would be difficult to imagine doing science without any measurements.
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Why is scientific notation useful?
Using Scientific Notation
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Why is scientific notation useful?
Using Scientific Notation
Scientists often work with very large or very small numbers. Astronomers estimate there are 200,000,000,000 stars in our galaxy.
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Scientific notation is a way of expressing a value as the product of a number between 1 and 10 and a power of 10.
For example, the speed of light is about 300,000,000 meters per second. In scientific notation, that speed is 3.0 × 108 m/s. The exponent, 8, tells you that the decimal point is really 8 places to the right of the 3.
Using Scientific Notation
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For numbers less than 1 that are written in scientific notation, the exponent is negative.
For example, an average snail’s pace is 0.00086 meters per second. In scientific notation, that speed is 8.6 × 10-4 m/s.
The negative exponent tells you how many decimals places there are to the left of the 8.6.
Using Scientific Notation
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To multiply numbers written in scientific notation, you multiply the numbers that appear before the multiplication signs and add the exponents. The following example demonstrates how to calculate the distance light travels in 500 seconds.
This is about the distance between the sun and Earth.
Using Scientific Notation
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When dividing numbers written in scientific notation, you divide the numbers that appear before the exponential terms and subtract the exponents. The following example demonstrates how to calculate the time it takes light from the sun to reach Earth.
Using Scientific Notation
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SHOW calculator method...at same time with other computer...SMART VIEW
Show SMART BOARD presentation with Scientific Notation on how to use calculators... (on mtn.lion computer along with TI-84 emulator)
TI-30 primarily but could also show with TI-84 using TI-84 emulator now loaded...
I need to add the TI graphing calculator on this computer apparently...
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Using Scientific Notation - RECORD IN NOTES... A rectangular parking lot has a length of 1.1 × 103 meters and a width of 2.4 × 103 meters. What is the area of the parking lot?
Using Scientific Notation
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Read and Understand What information are you given?
Using Scientific Notation
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Read and Understand What information are you given?
Using Scientific Notation
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Plan and SolveWhat unknown are you trying to calculate?
What formula contains the given quantities and the unknown?
Replace each variable with its known value
Using Scientific Notation
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Look Back and CheckIs your answer reasonable?
Yes, the number calculated is the product of the numbers given, and the units (m2) indicate area.
Using Scientific Notation
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Look Back and Check2. Perform the following calculations. Express your answers in scientific notation AND standard form.
a. (7.6 × 10-4 m) × (1.5 × 107 m)
b. 0.00053 ÷ 29
3. Calculate how far light travels in 8.64 × 104 seconds. (Hint: The speed of light is about 3.0 × 108 m/s.)
Using Scientific Notation
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Look Back and Check2. Perform the following calculations. Express your answers in scientific notation and standard form.
a. (7.6 × 10-4 m) × (1.5 × 107 m)
= (7.6 x 1.5) x (10 -4 × 107)
= 11.4 x 103 m2
= 1.14 x 104 m2 in scientific notation
= 11,400 m2 in standard form
Also show on calculator...
Using Scientific Notation
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Look Back and Check2b. 0.00053 ÷ 29 - 1st change to sci. notation....
5.3 x 10-4 ÷ 2.9 x 101 =
(no scientific calc.method: (5.3 / 2.9) x (10-4 / 101)= 1.827586... round to significant figure 1.8 x 10-5 =
= .000018
with calculator using special exponential key functions:
5.3 EE -4 / 2.9 EE 1 = 1.83... EE -5 =
1.83 X 10 -5
Using Scientific Notation
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Look Back and Check3. Calculate how far light travels in 8.64 × 104 seconds. (Hint: The speed of light is about 3.0 × 108 m/s.)
(8.64 x 104) x (3.0 × 108)
=25.92 x 1012 m
= 2.592 x 1013 m
rounded to significant figures 2.6 x 1013 m
Using Scientific Notation
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CW: Finish all labs and turn in lab reports before you leave school today....*Helicopter Lab*Check Lab*Golf/Ramp lab (Pre-AP required) - Reg. only for those who had started previously and are caught up with other notes...CW: Finish any previous notes that you didn’t complete from this week after labs. The paragraph in last part of notes stays stapled with notes packet.HW: Scientific Notation Problems due on TUESDAY next week...
Pre-AP: Start on Scientific Notation Lab if time and/or work on study guide questions...
Pre-AP - put “Writing in Science Question” in box if you had failed to complete this previously from pg. 11... Last chance to add points back into your grade...
Notes also available from home now in PPT version...
1.3 Measurement
The following website is a good place to practice converting scientific notation and also computing with scientific notation for multiplication/division as well as addition/subtraction...
I am going to create a quick lab to do some practice problems with this...This site is good because it allows students to enter answers, then check to see if correct. It does, however, allow them to skip problems which I didn’t care for...I didn’t care that it also showed negative numbers and didn’t have any examples of rounding off and then using sci. notation...http://janus.astro.umd.edu/cgi-bin/astro/scinote.pl
scientific notation practice with triple AAA math & uses “e” notation... not necessarily good since state would count that incorrect... if students http://www.aaamath.com/dec71ix2.htm
Scientific Notation - self practice with answers available with click of button.http://regentsprep.org/Regents/math/ALGEBRA/AO2/page5a.htm
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What units do scientists use for their measurements?
SI Units of Measurement
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Scientists use a set of measuring units called SI, or the International System of Units.
• SI is an abbreviation for Système International d’Unités.
• SI is a revised version of the metric system, originally developed in France in 1791.
• Scientists around the world use the same system of measurements so that they can readily interpret one another’s measurements.
SI Units of Measurement
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If you told one of your friends that you had finished an assignment “in five,” it could mean five minutes or five hours. Always express measurements in numbers and units so that their meaning is clear.
These students’ temperature measurement will include a number and the unit, °C.
SI Units of Measurement
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Base Units and Derived Units SI is built upon seven metric units, known as base units.
• In SI, the base unit for length, or the straight-line distance between two points, is the meter (m).
• The base unit for mass, or the quantity of matter in an object or sample, is the kilogram (kg).
SI Units of Measurement
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Additional SI units, called derived units, are made from combinations of base units.
• Volume is the amount of space taken up by an object.
• (cubic units of length or liters if liquid volume.)
• Density is the ratio of an object’s mass to its volume:
SI Units of Measurement
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To derive the SI unit for density, you can divide the base unit for mass by the derived unit for volume. Dividing kilograms by cubic meters yields the SI unit for density, kilograms per cubic meter (kg/m3).
A bar of gold has more mass per unit volume than a feather, so gold has a greater density than a feather.
SI Units of Measurement
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Seven metric base units make up the foundation of SI.
SI Units of Measurement
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Specific combinations of SI base units yield derived units.
SI Units of Measurement
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VISUAL - with powers of 10 size - galaxy to Quarks of an atom...
http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/
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Metric Prefixes The metric unit is not always a convenient one to use. A metric prefix indicates how many times a unit should be multiplied or divided by 10.
SI Units of Measurement
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Understanding metric prefixes - symbols, values, & multiplierhttp://www.aaamath.com/B/mea212x2.htmhttp://www.aaamath.com/B/mea612x3.htmhttp://www.aaamath.com/B/mea212x3.htm
includes symbols not required to know for testing purposes...http://www.aaamath.com/B/mea612x4.htm
values of metric symbols...http://www.aaamath.com/B/mea212x4.htmhttp://www.aaamath.com/B/mea612x2.htm
in words - easier valueshttp://www.aaamath.com/B/mea212x5.htmhttp://www.aaamath.com/B/mea612x5.htm
easy metric equivalency quiz - not good distractors...http://www.quiz-tree.com/Units_of_Measurement_main.html
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1 m = _____ dm
1 m = ______ cm
1 m = ______ mm
1 m = ___________μm
1 km = ___________ m
1 g = ____ dg
1 g = ____ cg
1 g = _____ mg
1 g = ______________ μg
1 kg = ___________ g
PASS OUT CONVERSION SHEET TO ASSIST WTIH CONVERSIONS.
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1 m = 10 dm
1 m = 100 cm
1 m = 1000 mm
1 m = 1,000,000 μm
1 km = 1000 m
1 g = ____ dg
1 g = ____ cg
1 g = _____ mg
1 g = ______________ μg
1 kg = ___________ g
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Practice with converting between metric units (length) - can be done with 20 questions, timed to get as many as possible, or timed for 60 seconds.... http://www.aaamath.com/B/mea69x10.htmsame thing with (volume)http://www.aaamath.com/B/mea69_x9.htmsame thing with metric masshttp://www.aaamath.com/B/mea69_x8.htm
Determinining what if metric amounts (lengths) are same, larger, smaller...(3 ways)http://www.aaamath.com/B/mea69_x6.htm#section2comparing metric volumes...http://www.aaamath.com/B/mea69_x7.htmhttp://www.aaamath.com/B/mea69_x5.htmcomparing metric masshttp://www.aaamath.com/B/mea69_x4.htm
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For example, the time it takes for a computer hard drive to read or write data is in the range of thousandths of a second, such as 0.009 second. Using the prefix milli- (m), you can write 0.009 second as 9 milliseconds, or 9 ms.
SI Units of Measurement
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Metric prefixes can also make a unit larger. For example, a distance of 12,000 meters can also be written as 12 kilometers.
Metric prefixes turn up in nonmetric units as well. If you work with computers, you probably know that a gigabyte of data refers to 1,000,000,000 bytes. A megapixel is 1,000,000 pixels.
SI Units of Measurement
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A conversion factor is a ratio of equivalent measurements used to convert a quantity expressed in one unit to another unit.
To convert the height of Mount Everest, 8848 meters, into kilometers, multiply by the conversion factor on the left.
SI Units of Measurement
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To convert 8.848 kilometers back into meters, multiply by the conversion factor on the right. Since you are converting from kilometers to meters, the number should get larger.
In this case, the kilometer units cancel, leaving you with meters.
SI Units of Measurement
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How does the precision of measurements affect the precision of scientific calculations?
Limits of Measurement
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Limits of Measurement
Precision Precision is a gauge of how exact a measurement is.
Significant figures are all the digits that are known in a measurement, plus the last digit that is estimated.
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The precision of a calculated answer is limited by the least precise measurement used in the calculation.
Limits of Measurement
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Limits of Measurement
A more precise time can be read from the digital clock than can be read from the analog clock. The digital clock is precise to the nearest second, while the analog clock is precise to the nearest minute.
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Limits of Measurement
If the least precise measurement in a calculation has three significant figures, then the calculated answer can have at most three significant figures.
• Mass = 34.73 grams • Volume = 4.42 cubic centimeters.
•
Rounding to three significant figures, the density is 7.86 grams per cubic centimeter.
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Limits of Measurement
Accuracy Another important quality in a measurement is its accuracy. Accuracy is the closeness of a measurement to the actual value of what is being measured.
For example, suppose a digital clock is running 15 minutes slow. Although the clock would remain precise to the nearest second, the time displayed would not be accurate.
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A thermometer is an instrument that measures temperature, or how hot an object is.
Measuring Temperature
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Measuring Temperature
Celsius (centigrade)temperature scale
Fahrenheit scale
Capillary tube
Colored liquid The liquid moves up and down the capillary tube as the temperature changes.
Bulb The bulbcontains thereservoir of liquid.
Scale The scale indicates thetemperature according to howfar up or down the capillarytube the liquid has moved.
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Measuring Temperature
Compressedscale
Liquid risesless in awide tubefor the sametemperaturechange.
Liquid risesmore in anarrow tubefor the sametemperaturechange.
Expanded,easy-to-read scale
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Temperatures can be expressed in degrees Fahrenheit, degrees Celsius, or kelvins.
Measuring Temperature
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The two temperature scales that you are probably most familiar with are the Fahrenheit scale and the Celsius scale.
• A degree Celsius is almost twice as large as a degree Fahrenheit.
• You can convert from one scale to the other by using one of the following formulas.
Measuring Temperature
Examples: What would C be if F is 68? What is F if C is 15?
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The SI base unit for temperature is the kelvin (K).
• A temperature of 0 K, or 0 kelvin, refers to the lowest possible temperature that can be reached.
• In degrees Celsius, this temperature is –273.15°C. To convert between kelvins and degrees Celsius, use the formula:
Measuring Temperature
Examples, what will K be if C is 17? What if K is 373? What is K if F is 122?
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Practice activity with converting between temperature scales...info. at top and then practice and check answers...
http://www.aaamath.com/B/mea414x2.htmCelsius to Fahrenheit Level 1http://www.aaamath.com/B/mea514x2.htmLevel 2 Celsius to Fahrenheit
http://www.aaamath.com/B/mea514x2.htmFahrenheit to Celsius Level 1http://www.aaamath.com/B/mea514x3.htmLevel 2 Fahrenheit to Celsius
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Assessment Questions
1. A shopping mall has a length of 200 meters and a width of 75 meters. What is the area of the mall, in scientific notation? a. 1 × 103 m2
b. 1.5 × 103 m2
1. 1.5 × 104 m2
a. 1.75 × 104 m2
1.3 Measurement
Assessment Questions
1. A shopping mall has a length of 200 meters and a width of 75 meters. What is the area of the mall, in scientific notation? a. 1 × 103 m2
b. 1.5 × 103 m2
1. 1.5 × 104 m2
a. 1.75 × 104 m2
ANS: C
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Assessment Questions
2. A student measures the volume and mass of a liquid. The volume is 50.0 mL and the mass is 78.43 g. What is the correct calculated value of the liquid’s density? (A calculator reads 1.5686.) a. 1.6 g/cm3
b. 1.57 g/cm3
c. 1.569 g/cm3
d. 1.5686 g/cm3
1.3 Measurement
Assessment Questions
2. A student measures the volume and mass of a liquid. The volume is 50.0 mL and the mass is 78.43 g. What is the correct calculated value of the liquid’s density? (A calculator reads 1.5686.) a. 1.6 g/cm3
b. 1.57 g/cm3
c. 1.569 g/cm3
2. 1.5686 g/cm3
ANS: B
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Assessment Questions
3. How can you convert a temperature expressed in kelvin (K) to degree Celsius (°C)? a. add 32
b. subtract 32
c. add 273
d. subtract 273
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Assessment Questions
3. How can you convert a temperature expressed in kelvin (K) to degree Celsius (°C)? a. add 32
b. subtract 32
c. add 273
d. subtract 273
ANS: D
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Assessment Questions
1. The SI base unit for length is the mile.
TrueFalse
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Assessment Questions
1. The SI base unit for length is the mile.
TrueFalse
ANS: F, meter