Conduction, Convection, and Radiation

1. Conduction, Convection, and Radiation

2. Copy down notes that are written in PURPLE!

3. Heat Energy • Energy is what makes it possible for things to move and for processes to happen. • All materials are made of tiny particles called molecules. • Molecules are always moving. • Heat is the energy given off by molecules moving. • The amount of heat depends on how fast the molecules move. Faster = more heat! • As the molecules move faster, they take up more space and make the object expand.

4. Let’s model this! • Stand up and put your hands out in front of you. • When told to start, move in RANDOM DIRECTIONS. • If you bump into someone, pat their hands LIGHTLY. • How is heat being generated?

5. Heat Transfer • Heat can be transferred from one object to another in 3 different ways: • Conduction • Convection • Radiation

6. Taking notes on your own… • Share a device with a partner. • Write the notes that are in purple. • Try the demonstrations when directed to.

7. How Heat Is Transferred

8. Conduction • Conduction refers to heat transfer from one SOLID to another SOLID. • As molecules heat up they move faster and expand. • When you touch one hot surface to another, the hot molecules bump into the other molecules which makes them start to move faster. • An object gets hotter from the movement of the molecules. • All solid objects conduct heat. • Some are better conductors than others. • Metals are good conductors of heat.

9. Go to Station #1 • Try conducting heat through a metal spoon. • Try conducting heat through the bag of ice.

10. Examples of ConductionList three examples by writing about 3 of the pictures..

11. Convection • Convection refers to heat traveling through liquids or gases, like water or air. • As molecules heat up, the heat makes the molecules move more rapidly and expand. • This creates currents in liquids or gases – hot air rises and cold air sinks. • Uneven heating of our ocean creates ocean currents. • Uneven heating of our atmosphere produces huge convection wind currents. • Scientists use global and local wind patterns to predict weather.

12. Go to Station #2 • Experience a heat convection current with the hair dryer. • Experience a cold convection current with the fan.

13. Examples of Convection List two examples by writing about what the picture is showing..

14. Radiation • Radiation refers to the release of invisible heat energy waves from the sun or fire. • There is no movement of molecules to transfer heat. • You can feel warmth without touching the source because the heat radiates. • Heaters and radiators get their name from this type of heat. • When the radiant energy from the sun hits the earth, the earth soaks up the energy and changes it into heat.

15. Go to Station #3 • Feel the warmth radiated by the different sources.

16. Examples of Radiation List two examples by writing about the picture.

17. Balance of Heat • Whenever a hot object is placed near a cold object, the hot object will transfer heat to the cold object until they reach a state of balance. • Balance happens when the temperatures of both objects are the same. • The fast moving molecules mix with the slow moving molecules until they are all mixed and balanced.

18. Thermal Equilibrium • The scientific words for balance of heat is thermal equilibrium.

19. Methods of Heat Transfer Conduction • Heat traveling through solids. • Two objects must touch Convection • Heat traveling through liquids or gases Radiation Release of invisible heat energy waves from the sun or fire. No movement of molecules