1. Unit 1: Introduction to Biology
The Metric System
Vodcast 1.2

2. Why Do Scientists Need a Common System of Measurement?
Researchers need to replicate each other’s experiments, and most experiments involve measurements, so scientists need a common system of measurement
Most scientists use the metric system when collecting data and performing experiments
Metric system – decimal system of measurement whose units are based on certain physical standards and are scaled on multiples of 10
Each unit is 10 times larger or 10 times smaller than the next unit
A revised version of the original metric system is called the International System of Units (SI)

3. The Metric System King Henry Died By (base unit: g, L, m) Drinking
Common SI Prefixes
Prefix
Symbol
Meaning
kilo- k
1000 times larger
hecto- h
100 times larger
deka- da
10 times larger
deci- d
10 times smaller
centi- c
100 times smaller
milli- m
1000 times smaller
micro- μ
1 million times smaller
nano- n
1000 million times smaller
King
Henry
Died
By (base unit: g, L, m)
Drinking
Chocolate
Milk

4. Understanding the Metric System
*Each step UP is 10 times LARGER kilo_____ (k_) hecto_____ (h_) deca_____ (da_) Base Unit (g, m, L) deci_____ (d_) centi_____(c_) milli_____(m_) *Each step down is 10 times smaller

5. Commonly Used Metric Units
Length (m = meter)
used to measure length or distance from one point to another
1000 meters = 1 kilometer (km)
Volume (L = liter)
used to measure volume of a liquid, or the amount of space an object takes up
1 liter = 1000 milliliters (mL)
Mass (g = grams)
used to measure mass, or the amount of matter in an object
1000 grams = 1 kilogram (kg)

6. Commonly Used Metric Units Continued…
Temperature ( °C = Celsius)
used to measure the warmth or coldness of an item, or its temperature, you use the unit degrees °
0°C = freezing point of water
100°C = boiling point of water