1. Metrics & SI Units

2. Standards of Measurement
Standard – an exact quantity that people agree to use for comparison
In Science, all countries use SI Units or the metrics system of measurement

3. Measurements & SI Units
Variable Measured
SI Unit
Symbol
Length
Meter m
Mass
Kilogram kg
Temperature
Kelvin K
Time
Second s
Amount of a substance
Mole
mol
Electric current
Ampere A

4. Measurements
Metric prefixes aid us in measuring very large or small quantities
All measurements consist of
a number
a unit

5. King Henry Died (by) Drinking Chocolate Milk
Kilo-
Hecto-
Deka-
BASE UNIT
(Meter, Liter, Gram)
deci-
centi-
milli-
Convert from one unit prefix to another by moving the decimal the appropriate number of spaces in a given direction

6. Moving the decimal??
Since the metric system is based on factors of TENS, we are able to simply move decimals when converting from one unit to another.
But… WHAT are we doing when we move the decimal?
If you move the decimal to the RIGHT you are MULTIPLYING your number by a factor of TEN
If you move the decimal to the LEFT you are DIVIDING your number by a factor of TEN

7. Move the decimal THREE places to the LEFT…
Convert mL into L
Kilo-
Hecto-
Deka-
BASE UNIT
(Meter)
Deci-
Centi-
Milli-
Move the decimal THREE places to the LEFT…
You are DIVIDING BY 1000
1453.2mL = L

8. Move the decimal SIX places to the RIGHT…
Another example...
Convert kg into mg
Kilo-
Hecto-
Deka-
BASE UNIT
(gram)
Deci-
Centi-
Milli-
Move the decimal SIX places to the RIGHT…
You are MULTIPLYING BY 1,000,000
kg = mg

9. Question #1 72.95cm = _______m 72.95cm = 0.7295m
Practice:
Question # cm = _______m 72.95cm = m
Question #2
3713.2m = ______km
3713.2m = km

10. Derived units
Sometimes SI units can be combined to create derived units
EXAMPLE
Volume = length x width x height = cm3
Density = mass = g/mL
volume
Speed = meters = m/s
second

11. Terms to Know Volume Mass Density
The amount of space occupied by an object
Can either use the formula or a method known as volume or water displacement.
Mass
The amount of matter in an object
Density
The amount of matter in a particular amount of space