1. Using Numerical Units in Science
Honors Biology

2. Warm Up Questions
Think about a pizza: what is the difference between a whole pie and a slice???
What problems could arise from the way different people count pies and slices?
Write your answers in your notebook

3. What is a Unit?
A unit is label given to a number that enables us to understand the size and quantity we are talking about
Examples of units: pounds, inches, centimeters, grams. . .

4. In science, we don’t count pizzas. . .
. . .but we do count and measure objects as groups and as fractions of a whole item.
Examples:
How many milliliters are in your water sample?
How many grams fit in a 1 kilogram container?

5. Two Systems of Units International System of Measurements (SI)
System of measurement used in Europe and Canada
Meters, grams, liters, and seconds are all units of SI
English System
System of measurement used in the United States
Miles, inches, pounds, and gallons are all units of the English system

6. SI = SCIENCE UNITS Time = seconds (s) Length = meters (m)
Mass = grams (g)
Volume = liters (l)

7. Are these measurements ok for science?
Andy measures time in seconds.
Sarah reports volume in gallons.
James collects data on distance in miles.
YOUR TURN: Write a correct science measurement scenario.

8. Science and SI SI is used because it is a decimal system based on tens
SI prefixes give the reader a clear relative size when the reader understands the system!!!

9. Converting Values in SI
To change how we talk about a given number, add the correct prefix to the unit
Examples:
1000 meters = 1 kilometer
1/100 meter = 1 centimeter

10. Confused? Remember that we do this all the time without thinking. . .
1 pizza pie = 8 slices
1 dozen = twelve items
. . . we are just FORMALIZING the process for science

11. SI prefixes used for counting GROUPS of items
Kilo (k) = (1000)
Example: 1 kilometer = 1000 meters
Hecta (h) = (100)
Generate an example!!!
Deca (D) = (10)

12. SI Prefixes used for counting portions of an item
Deci (d) = (0.1)
Example: 10 deciliters make up one liter
Centi (c) = (0.01)
Generate an example!!!
Milli (m) = 10-3 (0.001)
Micro (µ) = 10-6 ( )
Nano (n) = ( )

13. Your turn!!! Let’s get thinking about these new vocabulary words. . .
“Metric Measurements” Worksheet