1. Conceptual Physics Heat Transfer 02b: Convection, Radiation beodom.com

2. Convection – A means of heat transfer by movement of the heated substance itself. – Heat is moved with the molecules. Convection occurs in all liquids and gasses.

3. Convection Archimedes’ Principle – Warmer fluids are buoyed up by cooler (denser) surrounding fluids. Lava lamp – Heated wax blob becomes less dense and gets pushed up by cooler surrounding alcohol. – Once at top, wax cools becoming more dense and falling thus buoying up the less dense blobs.

4. Rheoscopic fluid demo

5. Convection Demo – boiling ice water – Can you explain the phenomena? – Predict what would happen if the ice were floated on top and the test tube was heated from the bottom. wn.com

6. Convection Flames – How does air move near a flame? – How does air move near a flame in SPACE? reclusland.com

7. Convection Soaring in gliders makes use of “thermals”… which reflects an understanding of how different materials give off thermal energy creating convection currents.

8. Convection Coastal Winds – Day Warm air rises pulling into land cooler air from the ocean. Winds TOWARDS the shore. – Night Warm air rises from the ocean pulling cooler air from land. Winds AWAY from the shore.

9. Convection With your mouth wide open, blow on your hand. Notice the temperature of your breath. Now pucker your lips to make a small opening with your mouth and blow on your hand again. Does the temperature of your breath change? In which case does your exhaled breath expand more? Why does it feel colder? When air expands, it cools. vectorstock.com free-press-release.com

10. Radiation – Transmission of radiant energy (THERMAL ENERGY) in the form of electromagnetic (EM) waves; antonine-education.co.uk

11. Radiation How does the sun warm the Earth? – Conduction? NO! Space is a vacuum! – Convection? NO! Only occurs AFTER energy is absorbed by the Earth and heats the air immediately above surface. Radiation! ( light, tiny packets of energy) – Radio waves – Microwaves – Infrared – Visible – Ultraviolet – X rays – Gamma rays

12. Radiation EM radiation … the thermal aspect NOT VISIBLE aspect!! ALL EM radiation is “visible.”

13. Radiation ALL objects emit EM radiation! Hotter objects emit more radiation toward higher energy part of the spectrum. Thermal energy enters as visible light, is absorbed, and since it is only 20 ˚C, it is emitted mainly in infrared spectrum. Infrared (IR) thermometer measures peak wavelength of IR radiation; just below the visible spectrum.

14. Infrared lamp and safety goggles demo

15. Radiation What is meant by the “greenhouse effect?” – “trapping” of IR radiation! What traps this infrared radiation? – Greenhouse gasses CO 2 Methane Water HFC’s Nest time: Greenhouse Gas Lab!