1 / 26

Objectives

Starter – copy and complete this passage in the front of your book under today’s date and the title Thermal energy.

feryal
Download Presentation

Objectives

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Starter – copy and complete this passage in the front of your book under today’s date and the title Thermal energy. • Energy is measured in ____________ and it has the symbol (J). Thermal is the science word for _________. Thermal energy can be transferred in ________, liquids, _______ and vacuums. There are three different ways that heat can be transferred: ___________, convection and __________.

  2. Objectives • To understand how heat can travel in solids. • To be able to explain conduction using a model. • To be able to explain the affect of heating a solid.

  3. Ball and ring • What happened to the ball when you heated it? • What happened to the ball when you cooled it?

  4. Bimetallic strip • What happened to the strip when it was heated? • What happed to the bimetallic strip when it was cooled?

  5. Explaining conduction • Can only happen in solids. • Thermal energy causes the particles to move faster. • Thermal energy transferred from warm areas to cold areas.

  6. Do all substances conduct at the same rate? Metal rods Drawing pin with vaseline on the back. T T T Cotton wool Hot water Beaker

  7. In your notes • How did you make the experiment a fair test? • Do all materials conduct heat at the same rate?

  8. Why does metal feel colder than wood, if they are both at the same temperature? Metal is a conductor, wood is an insulator. The metal conducts the heat away from your hands, the wood does not conduct the heat away from your hands as well as the metal, so the wood feels warmer than the metal.

  9. Starter – have a think! True or false? • Potential energy is the same as thermal energy. • Joules are the unit of energy. • Energy can be made. • Energy can be transferred. • Energy can’t be destroyed. • KJ is the symbol for joules.

  10. Objectives • To understand how heat can travel in gases and liquids. • To be able to explain convection using a model. • To be able to explain the affect of heating a liquid.

  11. Demonstration • Convection current is caused. • Density causes the current. • Can only occur in liquids and gases.

  12. Convection  The movement of hotter areas in a liquid can be seen using potassium permanganate as a dye: This cycle is called a convection current.  Can you explain how the convection current moves using the idea of density? The diagrams on the left will help you. H E A T

  13. Convection  The movement of hotter areas in a liquid can be seen using potassium permanganate as a dye: This cycle is called a convection current.  Can you explain how the convection current moves using the idea of density? The diagrams on the left will help you. H E A T

  14. Conclusion

  15. Water movement Cools at the surface Convection current Hot water rises Cooler water sinks

  16. What happens to the card? Explain why the card moves in this way. Use the words: density, air, particles. Convection in air

  17. Plenary • Why do you get a breeze at the seaside?

  18. Plenary

  19. Have a think! • How does the sun’s energy reach Earth?

  20. Radiation There are no particles between the Sun and the Earth so it CANNOT travel by conduction or by convection. RADIATION ?

  21. Objectives • To understand how heat can travel in a vacuum. • To be able to explain radiation. • To be able to explain how different surfaces affect radiation.

  22. Heat radiation • Travels as waves in a straight line. • Can travel in a vacuum. • It is strongly dependant on the surface.

  23. Which surface is hotter? Why is there a difference in temperature of the surface? Leslie’s Cube (Emitting radiation) Hot water Matt black Shiny silver

  24. Which ball bearing falls the quickest? Why do the ball bearings fall at different rates? The melting was trick (Absorbing radiation)

  25. Questions • Why do you feel hotter wearing a black top than any other colour? • Why do people paint their houses white in hot countries? • Why are shiny foil blankets wrapped around runners after a race?

  26. Plenary Radiation travels in straight lines True/False Radiation can travel through a vacuum True/False Radiation requires particles to travel True/False Radiation travels at the speed of light True/False

More Related