1. Measurements
Via

3. The Differences Numbers Measurements Mathematics is based on numbers
Science is based on measurements
All measurements have
Magnitude
Uncertainty
units
Numbers
Mathematics is based on numbers
Exact numbers are obtained by
Counting
Definition

4. Base SI Units Quantity Base Unit Symbol Length Meter m Mass Kilogram
Le Systéme Internationale (SI) units are standard in science
Quantity
Base Unit
Symbol
Length
Meter m
Mass
Kilogram kg
Time
Second s
Temperature
Kelvin K

5. Derived Units Area Length x length m2 Velocity Length/time m/s Density
Built from base SI units
Area
Length x length m2
Velocity
Length/time
m/s
Density
Mass/volume
Kg/m3

6. Very Large Units G (giga) means “one billion of”
M (mega) means “one million of”
k (kilo) means “one thousand of”

7. Very Small Units c (centi) means “a hundredth of”
m (mili) means “a thousandth of”
μ (micro) means “a millionth of”
n (nano) means “a billionth of”
p (pico) means “a trillionth of”

9. Significant Figures
Definition: digits up to and including the first uncertain digit
1.15 mL implies mL
Counting significant digits
Convert to scientific notation
Disappearing zeros just hold the decimal point – they aren’t significant

14. Strategy for Unit Conversion Problems
How many liters of gasoline do you have to buy to fill a 15 gallon tank?
Steps:
Identify the destination, including units
Choose a starting point
List the connecting conversion factors
Multiply starting measurement by conversion factors
Does the answer make sense?

15. Common Variation
Series of conversions
How many seconds in a year