1. Complete CRCT Warm-up for Thursday, Jan. 27 Please get your notes out. REMINDER--- due tomorrow! 1)Practice Sheet #19 2)Machine Design Project

2. THURSDAY, JANUARY 27, 2011 1. One property that all particles of matter have is they move constantly. TRUE

3. 2.Name the state of matter in which a.Particles are the closest together b.Moving the fastest c.Have a constant volume but not a constant shape -- SOLID -- GAS -- LIQUID

4. 2.Name the state of matter in which d.Electrons have separated from the nucleus e.No definite shape or volume f.Particles are close together but are moving past each other --PLASMA -- GAS -- LIQUID

5. Recall: Thermal energy travels as heat from a material of higher temperature to a material of lower temperature. Thermal energy will flow from warmer objects to cooler ones until the temperature equalizes.

6. Method #1 Conduction – transfer of thermal energy through matter by direct contact of particles Transfer by Collisions

7. Conduction can take place in solids, liquids and gases.

8. Matter must be present for conduction to take place!

9. Examples: Heating a pan on a stove (pan heats up by conduction) or place a spoon in a bowl of soup (spoon heats up by conduction)

10. Method #2 Convection – transfer of thermal energy by bulk movement of matter

11. Method #2 Transfer by currents

12. Convection can take place in fluids (materials that flow). Liquids and gases are fluids. Currents carry less dense, warmer material up while cooler, denser material sinks.

13. Matter must be present for convection to take place!

14. Examples: Ocean currents, wind, boiling water

15. Method #3 Radiation – transfer of thermal energy in the form of waves. Transfer by WAves

16. Energy that travels by radiation is often called radiant energy. Only radiant energy that is absorbed changes into thermal energy. Examples: Microwave heating food, sun’s energy heating a sidewalk

17. Different materials absorb radiant energy differently. MaterialEffect Shiny ________________ Dull________________ Dark colors________________ Light colors________________

18. Different materials absorb radiant energy differently. MaterialEffect Shiny Reflects radiant energy DullAbsorbs radiant energy Dark colorsAbsorbs radiant energy Light colorsReflects radiant energy

19. Most matter is divided into two groups – matter that easily allows heat to flow through it or matter that does not allow heat to travel easily through it.

20. Good thermal conductor – materials with many free electrons that can easily transport (atomic) kinetic energy Examples: iron, aluminum, silver copper

21. Insulators – materials that do not allow thermal energy (heat) to move easily through them Examples: wood, plastic, (trapped) air, plastic foam