1. Metric System
By Mr. M

2. NOT METRIC Foot Pound Inch Mile Gallon Fahrenheit
These may NEVER be in your units

3. The loss of the the Mars Climate Orbiter on September 23, 1999, was a most unfortunate and highly avoidable event.
The cause of the mishap has been traced to a mix-up over units. Preliminary findings indicated that one team used English units (e.g., inches, feet and pounds) while the other used metric units for maneuvers required to place the spacecraft in the proper Mars orbit.
The 'root cause' of the loss of the spacecraft was the failed translation of English units into metric units.
For nearly three centuries, engineers and scientists have been struggling with English units.

4. SI
The Système International
Main part of the metric system

5. Base Unit Base Quantity Name Symbol Time t second s Length l meter m
Mass m
kilogram kg
Temperature
T , Ө
kelvin K
Electric Current I
ampere A
Amount of Substance n
mole
mol
(not in A Level)
candela cd
Luminous Intensity

6. What you are measuring Mass = amount of material
Volume = space an object takes up
Temperature = amount of average kinetic energy
Density = how much is crammed into a space = mass divided by volume (grams/mL or grams/cm3)
Remember that an item sinks if it is more dense than what it is sitting in, so ice floats because it is less dense than water

7. Mass
Mass is not weight!!!!!!!!!!!!!!!!
Mass is measured on a scale like weight is
You have mass in space
Mass is a measure of how much matter you have

8. In weightlessness 454 grams is still 454 grams; however, 1 pound will be zero pounds in zero gravity.
What is the English unit for mass?
In the English system the unit for mass is the slug.
One slug sitting in Earth’s gravity has the weight of 32 pounds.

9. You may use any version of
Grams for mass
Liters for volume
Celsius for temperature
Seconds for time
Meters for length

10. Based on 10

11. Prefix kilo- k 10 3 1000 hecto- h 10 2 100 deka- D 101 10 Unit ? 100 1
deci- d
centi- c
milli- m
micro- mu
nano- n

12. Prefix plus root Kilogram means 1000 grams
Centiliter means 0.01 liters
Microsecond means seconds

13. 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

14. 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

15. 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

16. 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

17. Metric System
Now let’s start from centimeters and convert to kilometers
centimeters = 4 kilometers
centimeters = kilometers
kilo
hecto
deca
meter
liter
gram
deci
centi
milli

18. cubic centimeter cubic decimeter milliliter LITER
1 gram defined as the mass of one cubic centimeter of water (or one milliliter [mL] of water_.
cubic centimeter
cubic decimeter
milliliter
LITER

19. Density D = m/v Density is how much stuff is in one space
Units g/mL or g/cm3
Less dense objects float, more dense sink
Everything has a unique density so items can be identified by density
Water has a density of 1 g/mL

20. Dimensional Analysis
Set up a table where units are the same diagonally
Multiply by everything up top
Divide by everything in the bottom
Units cancel out, seconds multiplied by grams divided by grams = seconds

21. Convert 0.15 meters to centimeters
Starting amount
equal
End Amount
0.15 meters
1 centi
= centimeters
.01 meter
0.15 meters x 1
= 15 centimeters
.01

22. Convert 5234 millimeters to meters
Starting amount
equal
End Amount
5234 millimeters
0.001 m
= meters mm
52.34 meters

23. Convert 21 grams per liter (21 g/L) to milligrams per milliliter (mg/mL)
Starting amount
equal
equal
End Amount
21 grams Liter
mg 0.001g
0.001L mL
= mg mL

24. Works with any relationship: example is inches to meters
2.54 cm in an inch
100 cm in meter
Starting amount
equal
equal
End Amount
15 inches
2.54 cm 1 inch
1 m 100 cm
= m

25. Scientific Notation
The easy way of writing really big numbers or really small numbers
Note, this does not change units

26. M x 10n Scientific Notation M is the coefficient 1<M<10
10 is the base
n is the exponent or power of 10

27. Numbers less than 1 will have a negative exponent.
A millionth of a second is:
sec 1x10-6
1.0E x10^-6