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Keyword : Thermal, Heat, Radiation, Infra-red, Emit

Thermal Radiation. Keyword : Thermal, Heat, Radiation, Infra-red, Emit. Learning Objectives : Identify and explain. • The nature of thermal radiation. • That the amount of thermal radiation emitted increases with the temperature of the object.

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Keyword : Thermal, Heat, Radiation, Infra-red, Emit

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  1. Thermal Radiation Keyword: Thermal, Heat, Radiation, Infra-red, Emit

  2. Learning Objectives: Identify and explain • The nature of thermal radiation. • That the amount of thermal radiation emitted increases with the temperature of the object. I will be successful in this lesson if I can: • Use the connectives triangle with literate accuracy. • Use the keywords to ‘bingo’ your work throughout the lesson. • Work together as a team with all members effectively contributing in order to solve a problem (Team work, Effective Participator, Interpersonal) • • State that there is radiation, similar to light but invisible, that is emitted by all objects (Grade C). • • Explain that the hotter an object is the more infra-red radiation it emits (Grade C). • • Describe thermal radiation as electromagnetic waves (Grade C).

  3. STARTER The heat transfer mechanism in solids. Electrons in a metal that are free to move throughout the metal. A material that gives out thermal radiation A material that takes in thermal radiation. The heat transfer mechanism in fluids, which occurs because hot fluids are less dense than cold fluids. A material that lets heat flow through it. Absorber Conductor Conduction Convection Emitter Free Electrons

  4. Red Table Vincent – Fatima Alice - Balume Green Table Hayden – Chelsea Farrah - Ashleigh You thought you were safe didn’t you…. NO SUCH LUCK! Yellow Table Dominic – Emily Leon - Stephen Blue Table Russell – Tyron Carys - Sam MOVE…HUT HUT HUT…

  5. What are these pictures of? Why do they look different? HOW CAN YOU TELL IF SOMETHING IS HOT? Thermal radiation is electromagnetic radiation emitted from the surface of an object which is due to the object's temperature. An example of thermal radiation is the infrared radiation emitted by hot objects. A person near a fire will feel the radiated heat of the fire, even if the surrounding air is very cold. You cannot see the thermal radiation but you can see other energies (eg light). Explain this in a diagram! Title: Thermal Radiation

  6. How does the sun warm you on a hot day? Earth is warmed by heat energy from the Sun. How does this heat energy travel from the Sun to the Earth? ? infrared radiation There are no particles between the Sun and the Earth so the heat cannot travel by conduction or by convection. The heat travels to Earth by infrared waves. They are similar to light waves and are able to travel through empty space.

  7. INFRARED WAVES Heat can move by travelling as infrared waves. These are electromagnetic waves, like light waves, but with a longer wavelength. This means that infrared waves act like light waves: • They can travel through a vacuum. • They travel at the same speed as light – 300,000,000 m/s. • They can be reflected and absorbed. Infrared waves heat objects that absorbthem and so can be called thermal radiation.

  8. PYROMANIACS ANONYMOUS You are going to start a fire with a magnifying glass by finding its focal length! Okay, lets do a slightly more scientific investigation with thermometers and water. Any thoughts?

  9. Learning Objectives: Identify and explain • The nature of thermal radiation. • That the amount of thermal radiation emitted increases with the temperature of the object. I will be successful in this lesson if I can: • Use the connectives triangle with literate accuracy. • Use the keywords to ‘bingo’ your work throughout the lesson. • Work together as a team with all members effectively contributing in order to solve a problem (Team work, Effective Participator, Interpersonal) • • State that there is radiation, similar to light but invisible, that is emitted by all objects (Grade C). • • Explain that the hotter an object is the more infra-red radiation it emits (Grade C). • • Describe thermal radiation as electromagnetic waves (Grade C).

  10. Thermal Radiation 2 Keyword: Thermal, Heat, Radiation, Infra-red, Emit

  11. Learning Objectives: Identify and explain • The nature of thermal radiation. • That the amount of thermal radiation emitted increases with the temperature of the object. I will be successful in this lesson if I can: • Use the connectives triangle with literate accuracy. • Use the keywords to ‘bingo’ your work throughout the lesson. • Work together as a team with all members effectively contributing in order to solve a problem (Team work, Effective Participator, Interpersonal) • • State that there is radiation, similar to light but invisible, that is emitted by all objects (Grade C). • • Explain that the hotter an object is the more infra-red radiation it emits (Grade C). • • Describe thermal radiation as electromagnetic waves (Grade C).

  12. worst emitter best emitter silver matt black white worst absorber best absorber ABSORBING THERMAL RADIATION Infrared waves heat objects that absorb(take in) them. Some surfaces are better at absorbing thermal radiation than others – good emitters are also good absorbers. Matt black surfaces are the best absorbers of radiation. Shiny surfaces are the worst emitters because they reflect most of the radiation away. Why are solar panels that are used for heating water covered in a black outer layer?

  13. What do you think the definitions of ‘radiate’ and radiation’ are? Use hand signals & key words to explain it to your talking partner (as if they were a puppy!)

  14. worst emitter best emitter silver matt black white EMITING THERMAL RADIATION All objects emit (give out) some thermal radiation. Some surfaces are better at emitting thermal radiation than others. Matt black surfaces are the best emitters of radiation. Shiny surfaces are the worst emitters of radiation. Which type of kettle would cool down faster: a black kettle or a shiny metallic kettle?

  15. mmmm....? Why are shiny foil blankets wrapped around marathon runners at the end of a race? The shiny metal reflects the heat radiation from the runner back in to their body, which stops the runner from getting cold.

  16. SOLAR OVEN DEMONSTRATION Blah blah This is sooo boring…. Draw a diagram of your own solar oven to demonstrate how the light rays become focused to heat up the water.

  17. PYROMANIACS ANONYMOUS You are going to start a fire with a magnifying glass by finding its focal length! Okay, lets do a slightly more scientific investigation with thermometers and water. Any thoughts?

  18. Why are houses painted white in hot countries? White reflects heat radiation and so keeps the house cooler.

  19. How can we relate our new understanding to the greenhouse effect?

  20. Learning Objectives: Identify and explain • The nature of thermal radiation. • That the amount of thermal radiation emitted increases with the temperature of the object. I will be successful in this lesson if I can: • Use the connectives triangle with literate accuracy. • Use the keywords to ‘bingo’ your work throughout the lesson. • Work together as a team with all members effectively contributing in order to solve a problem (Team work, Effective Participator, Interpersonal) • • State that there is radiation, similar to light but invisible, that is emitted by all objects (Grade C). • • Explain that the hotter an object is the more infra-red radiation it emits (Grade C). • • Describe thermal radiation as electromagnetic waves (Grade C).

  21. Summary notes • Thermal or heat radiation is the transfer of energy by infra-red waves. These waves are part of the electromagnetic spectrum

  22. Summary notes • All objects emit (give off) thermal radiation. • The hotter the object the more thermal radiation it emits. • Heat radiation can travel through a vacuum like space. This is how we get heat from the sun. • Thermal radiation is energy transfer by electromagnetic radiation. • The transfer of heat energy by infra-red radiation does NOT involve particles.

  23. Summary notes • All objects emit (give off) thermal radiation. • The hotter the object the more thermal radiation it emits. • Heat radiation can travel through a vacuum like space. This is how we get heat from the sun. • Thermal radiation is energy transfer by electromagnetic radiation. • The transfer of heat energy by infra-red radiation does NOT involve particles.

  24. Check your understanding • Which part of the electromagnetic spectrum is concerned with heat energy? • How does heat from the Sun reach the Earth? • Do all objects give out the same amount of heat radiation? Explain your answer CLICK AGAIN FOR THE ANSWERS • ANSWERS: • Infra-red • By radiation through space. • No, the hotter the object the more heat it radiates

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