1. Introduction to Physical Science Monday, Wednesday, Thursday Tom Burbine tomburbine@astro.umass.edu

2. Midterm Thursday You can bring in one sheet of paper with anything written on it Covers everything up to Wednesday

3. Heat Transfer Conduction Convection Radiation

4. Conduction Transfer of internal energy by molecular and electronic collisions within a substance (especially a solid) Metals are good conductors since the electrons are held loosely Poor conductors are made up of molecules that hold tightly to their electrons

5. Convection Transfer of internal energy in a gas or liquid by means of currents in the heated fluid. The fluid flows, carrying energy with it

6. Radiation The transfer of energy by means of electromagnetic waves (forms of light)

7. Everything radiates energy Everything is also absorbing energy Black surfaces absorbs radiation better than white surfaces

8. Stefan-Boltzman Law

9. Thermal equilibrium is achieved when two systems in thermal contact with each other cease to have a net exchange of energy

10. Greenhouse Effect The greenhouse effect is the rise in temperature that a planet experiences because certain gases in the atmosphere (H 2 O, CO 2, CH 4, O 3 ) trap energy emitted from the surface.

11. Greenhouse Effect Visible light hits the surface Surface warms and emits infrared radiation Atmospheric gases absorb some of the infrared light Surface and atmosphere heat up

13. Stefan-Boltzman Law

17. Runaway Greenhouse Effect Runaway greenhouse effect to describe the effect as it occurs on Venus Venus is sufficiently strongly heated by the Sun that water is vaporized and so carbon dioxide is not reabsorbed by the planetary crust

19. Billion Metric Tons Carbon

24. Changes of phase

25. When matter changes phase When matter changes phase, a transfer of internal energy is involved

26. Changes of phase Evaporation –phase change from liquid to gas Sublimation – phase change from solid to gas Condensation – change of phase from a gas to a liquid

27. Evaporation cools the liquid left behind Condensation warms the object that it condenses on

28. Which is worse: A burn from 100 o C steam or 100 o C water?

29. After a shower, why are you colder outside the shower than inside the shower stall?

30. Any Questions?