1. Warm-Up: Put the following items in order from smallest to largest:
Shoe
Solar System
Water Molecule
Universe
Earth
Ant
Atlantic Ocean
Colorado
Milky Way
Peanut
Sand grain
Jupiter’s orbit
Atom

2. Answer: Atom (nm) Water molecule Sand grain Ant (mm) Peanut Shoe
Colorado (km)
Atlantic Ocean
Earth
Jupiter’s Orbit
Solar System (a.u.)
Milky Way
Universe (light years

3. Scientific Notation in Astronomy

4. Powers of Ten Website

5. What is Scientific Notation?
A short-hand way of writing
large numbers without
writing all of the zeros.

6. Why do we use scientific notation?
 Scientific Notation was developed in order to easily represent numbers that are either very large or very small. Here are two examples of large and small numbers. They are expressed in decimal form instead of scientific notation to help illustrate the problem.    The Andromeda Galaxy (the closest major galaxy to our Milky Way galaxy) contains at least 200,000,000,000 stars.
 On the other hand, the weight of an alpha particle, which is emitted in the radioactive decay of Plutonium-239, is ,000,000,000,000,000,000,000,006,645 kilograms.
 As you can see, it could get tedious writing out those numbers repeatedly. So, a system was developed to help represent these numbers in a way that was easy to read and understand: Scientific Notation.

7. The Distance From the Sun to the Earth
The distance of the Earth to the sun is 93,000,000 (93million miles).

8. Distance to the Sun in Scientific Notation: Step 1
Move decimal left
Leave only one number in front of decimal
Example:
93,000,000 =

9. Step 2
Write number without zeros
Example:
93,000,000 = 9.3

10. Step 3 7 93,000,000 = 9.3 x 10 Count how many places you moved decimal
Make that your power of ten
Example:
93,000,000 = 9.3 x 10 7

11. Practice Problem Standard to Scientific Notation
Write in scientific notation.
Decide the power of ten.
98,500,000 = 9.85 x 10?
64,100,000,000 = 6.41 x 10?
279,000,000 = 2.79 x 10?
4,200,000 = 4.2 x 10?
9.85 x 107
----->
6.41 x 1010
----->
2.79 x 108
----->
----->
4.2 x 106

12. More Practice Problems
On these, decide where the decimal will be moved.
734,000,000 = ______ x 108
870,000,000,000 = ______x 1011
90,000,000,000 = _____ x 1010
Answers
3) 9 x 1010
7.34 x 108
2) 8.7 x 1011

13. Complete Practice Problems (Start to Finish)
Write in scientific notation.
50,000
7,200,000
802,000,000,000
Answers
1) 5 x 104
2) 7.2 x 106
3) 8.02 x 1011

14. Scientific Notation to Standard Form
Move the decimal to the right
3.4 x 105 in scientific notation
move the decimal
--->
340,000 in standard form

15. Move the decimal to the right.
Write in Standard Form
Move the decimal to the right.
6.27 x 106
9.01 x 104
6,270,000
90,100