Energy on the Move!

1. Energy on the Move! HEAT How Thermal Energy is Transferred

2. Heat • Which has more thermal energy – an ice cube or your hand? • What happens to the ice cube in your hand? • Some of the thermal energy in your hand is transferred to the ice cube. • The particles begin to move faster. • The ice cube melts!

3. Heat • This transfer of thermal energy from one piece of matter to another is called heat. • Thermal energy naturally transfers from warmer matter to colder matter. Hot Matter Cold Matter Thermal Energy

4. Heat • When you walk in warm sand, some of the thermal energy from the sand moves to your feet. The soles of your feet get warmer. Thermal Energy

5. Heat • When your lips touch a cold can of soft drink, thermal energy is transferred from your lips to the can. Your lips loose thermal energy and get cooler. The can gains thermal energy and gets warmer. Thermal Energy

6. Three Ways Heat is Transferred • Conduction • Convection • Radiation

7. Conduction • If you have hot water running from a faucet, and you touch the outside of the faucet, what will it feel like? • It will feel hot, like the water. • The particles of hot water are moving fast, and bump into the particles of the faucet, causing them to start moving as well. • Thus, the faucet gets hot, too!

8. Conduction • The transfer of thermal energy by particles bumping into each other is called conduction. • This is how thermal energy moves from a burner on a stove to a metal pan. • This is also how you can get a painful burn if you touch the pan!

9. Conductors • Most metals conduct thermal energy as well. • They are good conductors. • Some kinds of matter do not conduct thermal energy so well. • A foam cup is a poor conductor of thermal energy.

10. Insulators • Materials that don’t conduct thermal energy well are called insulators. • That means that if a hot object is covered by an insulator, that thermal energy will not be easily transferred, and will likely stay where it is. • Thus, insulators can keep things hot!

11. Convection • When thermal energy is transferred through a liquid or gas, it is called convection. • As the air heats up, it is forced up by the cooler air. • As it cools, it sinks back down. • This is how a fireplace heats up a room.

12. Convection Air is heated up by the warm rising air • As the hot air is forced up, it warms the air around it. • As the hot air cools, it sinks back down. • The air can be warmed again, and it rises up again. • The air moves in a circle. • This is called a convection current. As air cools it sinks back down Hot air rises, pushed up by the cool air CONVECTION CURRENT

13. Convection How a hot air balloon stays afloat

14. Radiation • There is no matter between the sun and the Earth in space. • There is no matter for thermal energy to travel through. • Thermal energy from the sun cannot reach Earth through conduction or convection. • Bundles of energy that travel through matter and empty space are called radiation.

15. Radiation • You can sense some bundles of energy with your eyes. This radiation is visible light. • You can sense other bundles with your skin; these bundles are carrying heat. • Bundles of energy that carry heat are called infrared radiation. • Outside on a sunny day, your skin feels warm because of infrared radiation from the sun.

16. Conduction, Convection, and Radiation

17. Conduction, Convection, and Radiation

18. Thermal Energy Review • ______ is the transfer of thermal energy from one piece of matter to another. Heat

19. Thermal Energy Review • Thermal energy naturally moves from _____ matter to _____ matter. Cool Warm

20. Thermal Energy Review • The transfer of thermal energy by particles bumping into each other is called: ______ conduction

21. Thermal Energy Review • The thermal energy transfer in a liquid or gas is called:______ convection

22. Thermal Energy Review • This is an example of what type of thermal energy transfer? Convection

23. Thermal Energy Review • This is an example of what type of thermal energy transfer? Convection

24. Thermal Energy Review • How is energy transferred through empty space? Through infrared radiation.