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# Atoms and heat

Atoms and heat. “Absolute zero” refers to: The size of atoms A new form of energy Motion stopping A fighter jet A type of collision. Bose-Einstein condensation. Temperature = 170 x 10 -9 K = 170 nK. The average speed of the molecules in your desk is approximately: 2 inches/s [5 cm/s]

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## Atoms and heat

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1. Atoms and heat

2. “Absolute zero” refers to: • The size of atoms • A new form of energy • Motion stopping • A fighter jet • A type of collision

3. Bose-Einstein condensation Temperature = 170 x 10-9 K = 170 nK

4. The average speed of the molecules in your desk is approximately: • 2 inches/s [5 cm/s] • 1 ft/s [0.3 m/s] • 3 ft/s [1m/s] • 1000 ft/s [330 m/s] D) 900 million ft/s [300 million m/s]

5. August 6, 2010

6. Energy content of various sources

7. Temperature scales

8. Think back to the electrolysis we did last week. We made H2 and O2. Which molecule has a faster speed at room temperature? • Hydrogen • Oxygen • They’re the same speed

9. Moral of the tanker story? • Heat can melt containers • Use caution when transporting flammable materials • Pressure is proportional to temperature • Solids are much heavier than liquids • High internal pressure needs to be let out

10. Donut-shaped piece of metal. What happens to the hole if I heat this? • It gets bigger • It gets smaller • It stays the same size

11. y x What about a flat bar – if I heat it, will it expand more distance in the x or y direction? • x direction • y direction • same in both directions

12. Donuts again… Donut-shaped piece of metal. What happens to the hole if I heat this? • It gets bigger • It gets smaller • It stays the same size

13. Water seems to behave similar…

14. But it has strange behavior…

15. Density of water

16. Sea level rise predictions From wikipedia, referencing IPCC report 2009

17. Tues 14 Sept

18. Are you freaking out about tomorrow’s exam? • Not really • Sort of • Feeling confused on some stuff • Need to spend today getting seriously organized • Panic

19. What time of the year would you expect to get the best gas mileage out of your vehicle? A. Summer B. Winter C. About the same for both Why?

20. Which of the following are a heat engine? A) A coal fired electric generator B) A car engine C) A steam engine in an old fashioned train. D) A nuclear power plant's turbines E) All of the above

21. Suppose the gas of atoms bouncing around in the picture has a temperature of 25 C (about room temperature). How does the pressure on the walls change if I heat up the gas to 100 C? • Goes up by a factor of 4 • Goes down by a factor of 2 • Goes up by a factor of 25% • Goes up by a factor of 50% • Stays the same