1. Scale Principles of Physics

2. Why do we need to think in terms of scale? To understand the size of things we can’t see – How big is Earth? – How big is a red blood cell? Scale: relative size – Used to compare sizes

3. Road Map Most regular everyday use of scale How is the scale given?

4. Size of Earth Diameter of Earth = 12,740,000 m Can we understand how big 1.274 x 10 7 m is? How could we make that make sense to us? – Consider the distance around the high school track (400 m) – How many times would you have to run around the track to run the diameter of the Earth? 31,850 times

5. Size of a Carbon Nanotube Diameter of a Carbon Nanotube = 0.0000000013 m Can we understand how small 1.3 x 10 -9 m is? How could we make that make more sense to us? – Consider the distance around the high school track (400 m) How many nanotubes could fit next to each other around the high school track? 307,692,307,692 nanotubes – Consider a meter stick (1 m) How many nanotubes could fit next to each other along a meter stick? 769,230,769 nano tubes – Consider the diameter of the head of a pin (0.002 m) How many nanotubes could fit next to each other across the head of the pin? 1,538,462 nanotubes

6. Metric Powers of Ten tera- (T-)10 12 1 trillion giga- (G-)10 9 1 billion mega- (M-)10 6 1 million kilo- (k-)10 3 1 thousand hecto- (h-)10 2 1 hundred deka- (da-) 101 ten deci- (d-)10 -1 1 tenth centi- (c-)10 -2 1 hundredth milli- (m-)10 -3 1 thousandth micro- (µ-)10 -6 1 millionth nano- (n-)10 -9 1 billionth pico- (p-)10 -12 1 trillionth

7. Metric Powers of Ten How many times bigger is a kilometer than a meter? 1 kilometer = 1000 meters therefore A kilometer is 1,000 times bigger than a meter

8. Metric Powers of Ten How many times smaller is a nanometer than a millimeter? 1 millimeter = 0.001 m 1 nanometer = 0.000000001 m A millimeter is 1,000,000 times bigger than a nanometer

9. Metric Powers of Ten Is a nanometer bigger or smaller than 100 times a picometer? 1 picometer = 0.000000000001 m 1 nanometer = 0.000000001 m 100 times a picometer is 0.0000000001 m A nanometer is bigger