The metric system was devised in 1791 by the French Academy of Sciences to create a standardized system of measurement. It uses a base-10 system and standardized units like meters, liters, and grams that are related by powers of 10. Conversions between units are easy by moving the decimal point a place for each power of 10. The metric system was widely adopted and later renamed the International System of Units. It provides standardized units and prefixes to measure length, volume, mass, and temperature.

1. Metric System

2. First measurements
• Based on the human body
Example: foot, hand
• Standards evolved but not constant
• Lack of common units a problem

3. Solution
• 1791 French Academy of Sciences
devised metric system
– Metric means measure in French
– Based on unit of 10
• Easy to make conversions between units
– Widely adapted
• 1960 renamed International System of
Units (SI)

4. Metric Units
Unit Metric measure Abbreviation
Length Meter m
Volume Liter L
Mass Gram g
Temperature Celcius C

5. Metric prefixes we’ll use
Prefix Symbol Multiplier Notation
nano n 0.000000001 10-9
micro µ 0.000001 10-6
milli m 0.001 10-3
centi c 0.01 10-2
Base unit g, m, L 1 100
kilo k 1000 103

6. Metric System
• An easy way to move within the metric system is
by moving the decimal point one place for each
“step” desired
Example: change meters to centimeters
1 meter = 10 decimeters = 100 centimeters
or
1.00 meter = 10.0 decimeters = 100. centimeters
kilo hecto deca
meter
liter
gram
deci centi milli

7. 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

8. Metric conversion examples
15.2 millimeters = _________________ meters
13 centigrams= __________________ micrograms
9.74 liters = __________________ milliliters
8051 nanometers = ______________ micrometers

9. Scientific Notation
• You can work backwards from scientific
notation
– The number in the superscript position of the
10 tells you how many places to move the
decimal and in what direction
1 x 103
= 1000
4.7 x 105
= 470000
3.2 x 10-3
= 0.0032

10. Length: Meter (cm, mm)
• Based on the physical
measure on the earth
– Length from the North
Pole to the Equator
divided into 10 million
parts
• Measure with a ruler
or tape measurer

11. Mass/Weight: Grams (mg)
• The quantity of matter
in a material
• Gram is typical unit
used in the laboratory
• Measure with scale or
balance

12. Volume: Liter (ml)
• Space occupied
by a unit
– 3 dimensional
• Units are cubed
• ml=cm3
• Typically used to
measure liquids
• Meniscus:
curvature of water

13. Micropipette
• Tool used to
pipette small
volumes of liquids
• Measure in
microliters (10-6
)
• Will use this tool
again later in the
semester

14. Temperature: Celsius (C°)
• Measure of concentration of heat
• The average amount of motion per
molecule
0°C=freezing point of H2O
100°C=boiling point of H2O
To convert:
F to C: C = ( F - 32) / 1.8
C to F: F = C × 1.8 + 32