1. Do Now & Announcements Turn in HW to be checked Sig Figs Quiz
Scientific Notation, Unit Conversions Continued
Tomorrow: Review
Unit 1 TEST MON 8/31

2. Telephone
602,000,000,000,000,000,000,000
6.02 x 1023

3. Scientific Notation
Scientific notation is used to express very large or ­very small numbers more easily.
It is written as a (decimal between 1 & 10) x 10 raised to an exponent

4. How to express a number in terms of scientific notation:
1. Move the decimal point of your number so that you have a decimal between 1 and 10

5. How to express a number in terms of scientific notation:
2. Count the number of spaces (n) and which direction you moved the decimal point

6. How to express a number in terms of scientific notation:
3. If you moved the decimal point to the left multiply (x) your decimal by 10n
360,000  3.6 x 105
If you moved the decimal point to the right, multiply (x) your decimal by 10—n
 3.7 x 10—4

7. Category
Normal Number
Scientific Notation
Population of the World
7,125,000,000 people
Distance from the Earth to the Moon
240,000 miles
Raindrops in a Thundercloud
6,000,000,000,000 drops
Density of Oxygen
g/cm3
Mass of a Dust Particle kg

8. How to express a value given in scientific notation as a normal number:
1. Identify the exponent
3.6 x 105: exponent 5
3.7 x 10—4: exponent –4

9. How to express a value given in scientific notation as a normal number:
2. If the exponent is a positive number, move the decimal point the same number of places to the right
3.6 x 105: move decimal 5 places to the right

10. How to express a value given in scientific notation as a normal number:
3. If the exponent is a negative number, move the decimal point the same number of places to the left.
3.7 x 10—4: move decimal 4 places to the left

11. Category
Normal Number
Scientific Notation
Speed of Light
3.00 x 108 m/s
Distance from the Earth to the Sun
9.3 x 107 miles
Cells in the Human Body
1.0 x cells
Water on Earth’s Surface
1.40 x 108 square miles
Diameter of a Grain of Sand
2.4 x inches

12. x1000
x10
x10
x10
x10
x10
x10
x1000
x1000
Prefixes at the top of the chart represent a larger amount or quantity.
Prefixes at the bottom of the chart represent a smaller amount or quantity.  

13. Dimensional Analysis (aka Factor-Label Method, Unit-Factor Method)
Can be used to convert from one unit to another; it is based on the idea of cancelling out units!
It is super important to WRITE OUT ALL UNITS when doing this!

14. Ex: Convert 1609 meters into kilometers

15. Ex: Convert 1609 meters into kilometers

16. Ex: Convert 1609 meters into kilometers

17. Ex: Convert 1609 meters into kilometers

19. Unit Conversion Lab
Express your final answer using the correct # of sig figs and units
Note: don’t look at the “conversion factors” when determining lowest # of sig figs…only look at the given or measured value.