1. Scientific Measurement
Chapter 3
Scientific Measurement

2. 3.1 The importance of Measurement
Not all measurements give the same amount of information!
Qualitative measurements: give descriptive, non-numerical results (NO NUMBERS)
Think ‘quality’
Quantitative: give results with numbers and units (NUMBERS!
Think ‘quantity’. Quantity means numbers

3. Scientific notation
Scientific Notation: number is written as the product of two numbers: a number greater than or equal one and less than 10 and a power of 10. ex: 1,200 = x 103

4. How to write in scientific notation
1. Write the number you are starting with
2. Move the decimal behind the first digit in the number
Write ‘x 10’
Count the ‘jumps’ this is the ‘power of 10’
3. Decide if the new number is bigger or smaller than the old number
Bigger = negative jumps
Smaller = positive jumps

5. Let’s try it! 1,230, 900 Write the number: 1,230,900.00
Move the decimal:
Write x 10: x 10
Count the jumps: 6 jumps
Is the new number bigger or smaller than the old number? Smaller = positive jumps!
x 10 6

6. Let’s try another! 0.000045672 1. Write the number: 0.000045672
2. move the decimal:
3. write ‘x 10’: x 10
4. count the jumps: 5 jumps
5. is the new number bigger or smaller than the old number: Bigger = Negative!
x 10 -5

7. How to write in standard form
Standard form= this is just the regular way to write numbers
Look at the exponent (number on the x 10). If it is positive, make the number bigger. If it is negative, make the number smaller.
Count the jumps
Place new decimal

8. Let’s try it!
3.567 x 103
1. Look at the exponent: it is positive, so we have to make the number BIGGER
2. count the jumps: 3 jumps
3. place the new decimal
3,567 is the standard form

9. Let’s try another!
x 10 -6
Look at the exponent = negative: make number smaller!
2. count the jumps = 6 jumps
3. place new decimal

10. You try it! Write the following numbers in scientific notation:
1. 3,567,987
5. 6
6. 12,000

11. More Practice! Write the following numbers in standard form
x 106
x 103
x 10-2
x 10-8
x 10 10 x

12. You try it!
pg 53: 1-3 Pg 78: 36, 67, 79-83

13. Plug it in your calculator!
To enter a number in scientific method on a calculator:
1. Do you have a light blue or a dark blue calculator?
DARK BLUE:
Type in digit: ex
Hit the ‘2nd button’(light blue button, upper left)
Hit the ‘x-1’ button (above the ‘7’)
Your calculator should read ‘ E’
Enter exponent (power of 10)

14. Light Blue: Type in digit: ex. 1.2345 Hit ‘EE button’ (above ‘7’)
Your calculator should read E
Type in exponent (power of 10)

15. Now you can do operations with exponents!
Let’s try it!
1.234x x108 =
3.23x10-4 – 9.1x1014=
6.367x1023 x 7.67x108 =
2.112x1019 / 6.778x10-2=

16. Today’s challenge 1. Get into pairs
2. Design a 20 question quiz for scientific notation.
Can include operations, word problems, identification, whatever!
Include answer key
Best quiz? Becomes CLASS quiz! WINNERS EXEMPT AND GET 100%!!!!

17. 3.2 Accuracy in Measurements
Accuracy: a measure of how close a measurement comes to the actual value
Precision: a measure of how close a series of measurements are to one another
Error = experiemental value – accepted value
Percent error = |error|/accepted value x 100

18. Significant Figures in measurements
Significant figures: all of the digits that are known, plus the last digit which is estimated.
Think of 3 different rulers:
One broken into whole meters
One broken into decimeters
One broken into centimeters
Which is more precise? WHY?

19. You try it: Count the number of sig figs in each measurement
1. 1,
2. 19 birds in a tree
4. 23,013.00
5. 8,000,000
6. 303

20. ROUNDING!
When completing measurements in a lab setting, you must ROUND to the appropriate number of SIG FIGS!
1. underline the place value you are rounding to (nearest tenth, etc)
Draw an arrow to the digit behind that place value
3. ask yourself: “5 or above? Give it a shove”
“4 or below? Leave it alone!”

21. You try it: Round to the nearest tenth Round to the nearest hundredth
Round to the nearest whole number

22. Reading Instruments
In a lab, you will have to read instruments to the appropriate number of sig figs.
1. Read the instrument all the way
2. Estimate last digit (this is uncertain)
Ex. If your ruler goes to centimeters, your measurement will go to tenths of a centimeter
2.4 centimeters (the .4 centimeters is estimated)

23. More Practice:
Pg 58, # 5 and 6
Worksheet
Due at end of period

24. Today’s Challenge: Get into Pairs
Each of you separately mark a measurement on the blank sheets
Swap papers
Complete independently
Swap back and grade
How did you do?
Hand them in 

25. Wrap up! On a sheet of paper (to be collected by the end of period)
1. What are significant figures?
2. Why do we count them?
3. How do we read a measuring device to the appropriate number of significant figures?
4. What is different about the last digit of a measurement?
Pg 78: # 36-43

26. Significant figures in calculations
Addition and Subtraction: round to the same number of DECIMAL PLACES as the number with the LEAST number of decimal places
Multiplication and Division: round to the same number of SIGNIFICANT FIGURES and the number with the LEAST number of significant figures

27. Let’s try it: 61.2 meters + 9.35 meters + 8.6 meters =
LOWEST NUMBER OF DECIMAL PLACES? 61.2 OR 8.6 HAS ONE DECIMAL PLACE. ANSWER WILL BE ROUNDED TO ONE DECIMAL PLACE!!!
7.55 meters x 0.34 meter =
LOWEST NUMBER OF SIG FIGS? HAS 2 SIG FIGS. ANSWER WILL HAVE 2 SIG FIGS!!

28. More Practice: 9.44 meters – 2.11 meters =
8.3 meters x 2.22 meters =
8432 meters / 12.5 =
35.2 seconds / 60 =

29. Today’s Challenge! Get into pairs
Write a 20 question quiz on ONLY significant figures
Your quiz should include counting sig figs, rounding to the right number of sig figs, and calculations with sig figs
You must include an answer key
Winners receive 100% on quiz and are exempt tomorrow!

30. International System of Units
International system of units (SI)= revision of the metric system. Every unit is a multiple of 10.
This makes converting from one unit to another EASY!

31. Units of Measurement Length meter Volume cubic meter or liter
Mass kilogram
Density grams/cm3
Temperature kelvin or degrees Celsius
Time second
Pressure pascal or atmosphere
Energy joule

32. Prefixes
Prefixes are used to tell you how many multiples of 10 something is. Sometimes the SI unit isn’t a practical measurement. For example: meters to measure the size of an atom. Atoms are way too small to be measured in meters, it’s not practical! We use a smaller multiple of meters and denote it with a prefix (nanometers)

33. Volume Volume: the space occupied by a sample of matter
SI unit is milliliter or cubic centimeter
We often use liter to measure volume
WHY???

34. Mass Mass: the amount of matter in an object
Weight: measure of the pull of gravity on an object
Weight can change with location, mass can’t
SI unit = Kilogram
Kilo=1000
We often use grams in lab. WHY????

35. Density
Which is heavier, a pound of lead or a pound of feathers? What’s the difference between the two quantities? DENSITY!

36. Generally, density decreases as temperature increases.
Density = mass/volume
Matter with a lower density will float on matter with a higher density (liquids and gases)
Generally, density decreases as temperature increases.
water is most dense at 4 degrees Celsius
What happens with ice on water? What can you assume about the density of ice?
What happens when you fill a balloon with helium? What can you assume about the density of helium?

37. Specific Gravity
Specific Gravity: comparison of the density of an object to the density of water.
Specific gravity = density of object/density of water
Hydrometer: device used to measure the specific gravity of a liquid
Why do you think this comparison is made to WATER????

38. Practice!
Pg 67, 17-22
Pg 71, 23-24
Pg 72, 25-29

39. Dimensional Analysis
You must be able to convert from one unit to another. This skill will be used for the REST OF YOUR LIFE!!!!
1. start with what you know
2. write conversion factor as a fraction
3. what you want goes on top!
4. multiply or divide as necessary

40. Common Conversion factors
1 kilometer = 1,000 meters 1 centimeter = .01 meters 1 millimeter = .001 meters 1 hour = 60 minutes 1 yard = 3 feet 1 mole = 6.02 x 1023 particles

41. Let’s try one 273 meters to kilometers 1. start with what you know
2. Write conversion factor as a fraction
1 km = 1000 meters 1km/ 1000meters
3. What you want goes on top!
I want to end with kilometers, so it goes on top!
4. Multiply or divide as necessary
273 meters x 1 km/ 1000 m = km

42. Let’s try some more! Convert to meters: 267 cm 273 mm 273 km
Convert to hours
273 minute
Convert to yards
273 feet