1. Measurements

2. Measurement You are making a measurement when you Check you weight
Read your watch
Take your temperature
Weigh a cantaloupe
What kinds of measurements did you make today?

3. What is a Measurement?
Measurement: a comparison of an the dimension of object or substance to a known standard.
Dimension: a physical property of an object, any measureable property of an object
Standard: a known quantity that is universally accepted
Tool: an artificial object used to aid the senses in determining known standards for measurements

4. Standards of Measurement
When we measure, we use a measuring tool to compare some dimension of an object to a standard.

5. Some Tools for Measurement

6. Solution
From the previous slide, state the tool (s) you would use to measure
A. temperature thermometer
B. volume measuring cup, graduated cylinder
C. time watch
D. weight scale

7. In every measurement there is a Unit from measuring device
Stating a Measurement
In every measurement there is a
Number
followed by a
Unit from measuring device

8. What Universal System Do We Use?
SI- Systeme Internationale
Metric System- a system of measurement based on multiples or divisions of of 10
Why?
It is convenient
It is universally used amongst scientists, doctors, mathematicians, etc.

9. Metric System
The metric system is based on a base unit that corresponds to a certain kind of measurement
Length = meter
Volume = liter
Weight (Mass) = gram
Prefixes plus base units make up the metric system
Example:
Centi + meter = Centimeter
Kilo + liter = Kiloliter

10. The Metric System
The metric system is a measurement system based on our decimal (base 10) number system.
Other countries and all scientists and engineers use the metric system for measurement.

11. Common Dimensions and Their Given Units of Measure
Base Unit
Mass
Kilogram
Volume
Liter
Time
Seconds
Temperature
Kelvin
Length
Meter

12. What is the Length? We can see the markings between 1.6-1.7cm
We can’t see the markings between the .6-.7
We must guess between .6 & .7
We record 1.67 cm as our measurement
The last digit an 7 was our guess...stop there

13. Learning Check What is the length of the wooden stick? 1) 4.5 cm

14. Meters One centimeter is about the width of a large paper clip
or your fingernail.

15. Meters
A meter is about the width of a doorway

16. Gram
Grams are used to measure mass or the weight of an object.

17. Grams
A milligram weighs about as much as a grain of salt.

18. Liters
Liters measure liquids or capacity.
2 Liter Soda

19. Liter
1 milliliter is about the amount of one drop

20. Changing Metric Units
To change from one unit to another in the metric system you simply multiply or divide by a power of 10.

21. Metric System
So if you needed to measure length you would choose meter as your base unit
Length of a tree branch
1.5 meters
Length of a room
5 meters
Length of a ball of twine stretched out
25 meters

22. Metric System
But what if you need to measure a longer distance, like from your house to school?
Let’s say you live approximately 10 miles from school
10 miles = meters
16093 is a big number, but what if you could add a prefix onto the base unit to make it easier to manage:
16093 meters = kilometers (or 16.1 if rounded to 1 decimal place)

23. Metric Prefixes Prefix Symbol Factor Number Factor Word Kilo- k 1000
Metric Units
The metric system has prefix modifiers that are multiples of 10.
Prefix
Symbol
Factor Number
Factor Word
Kilo- k
1000
Thousand
Hecto- h
100
Hundred
Deca-
da or dk 10
Ten
Unit
m, l, or g 1
One
Deci- d .1
Tenth
Centi- c
.01
Hundredth
Milli- m
.001
thousandth

24. To change from a larger unit to a smaller unit, you need to multiply.
1 km x 1000 = 1000 m
1 m x 100 = 100 cm
1 cm x 10 = 10mm

25. To change from smaller units to larger units you divide by a power of ten.
1000mm ÷ 10 = 100cm
100cm ÷ 10 = 10dm
10dm ÷ 10 = 1m

26. Metric System The three prefixes that we will use the most are: kilo
centi
milli
kilo
hecto
deca
Base Units
meter
gram
liter
deci
centi
milli

27. Metric System
These prefixes are based on powers of 10. What does this mean?
From each prefix every “step” is either:
10 times larger or
10 times smaller
For example
Centimeters are 10 times larger than millimeters
1 centimeter = 10 millimeters
kilo
hecto
deca
Base Units
meter
gram
liter
deci
centi
milli

28. Metric System
Centimeters are 10 times larger than millimeters so it takes more millimeters for the same length
1 centimeter = 10 millimeters
Example not to scale 40 41
1 mm 40 41
1 cm

29. Metric System For each “step” to right, you are multiplying by 10
For example, let’s go from a base unit to centi
1 liter = 10 deciliters = 100 centiliters
2 grams = 20 decigrams = 200 centigrams
( 1 x 10 = 10) = (10 x 10 = 100)
(2 x 10 = 20) = (20 x 10 = 200)
kilo
hecto
deca
meter
liter
gram
deci
centi
milli

30. Metric System
Now let’s try our previous example from meters to kilometers:
16093 meters = decameters = hectometers = kilometers
So for every “step” from the base unit to kilo, we moved the decimal 1 place to the left (the same direction as in the diagram below)
kilo
hecto
deca
meter
liter
gram
deci
centi
milli

31. Metric System
If you move to the left in the diagram, move the decimal to the left
If you move to the right in the diagram, move the decimal to the right
kilo
Hecto
Deca
meter
liter
gram
deci
centi
milli

32. Metric System
Summary
Base units in the metric system are meter, liter, gram
Metric system is based on powers of 10
For conversions within the metric system, each “step” is 1 decimal place to the right or left
Using the diagram below, converting to the right, moves the decimal to the right and vice versa
kilo
hecto
deca
meter
liter
gram
deci
centi
milli

33. Place Values of Metric Prefixes
Thousand
Hundred
Ten
One
Tenth
Hundredth
Thousandth km kg kL hm hg hL
dkm
dkg
dkL m g L dm dg dL cm cg cL mm mg mL

34. Place Values of Metric Prefixes
Move the decimal point to the right to multiply.
Thousand
Hundred
Ten
One
Tenth
Hundredth
Thousandth km kL kg hm hL hg
dkm
dkL
dkg m L g dm dL dg cm cL cg mm mL mg

35. Place Values of Metric Prefixes
Thousand
Hundred
Ten
One
Tenth
Hundredth
Thousandth km kg kL hm hg hL
dkm
dkg
dkL m g L dm dg dL cm cg cL mm mg mL

36. Place Values of Metric Prefixes
Move the decimal point to the left to divide.
Thousand
Hundred
Ten
One
Tenth
Hundredth
Thousandth km kL kg hm hL hg
dkm
dkL
dkg m L g dm dL dg cm cL cg mm mL mg

37. Place Values of Metric Prefixeskm kg kL hm hg hL
dkm
dkg
dkL m g L dm dg dL cm cg cL mm mg mL
3km
30hm
300dkm
3000m 4L
30000dm
300000cm
12cm mm

38. Accuracy and Precision