Quick Quiz - What do you remember from last lesson? Which types of materials are best at reflecting radiation? What do we call an object which gives out a lot of radiation? What do metals have that make them so good at conducting? Hot particles rise because they are less dense. Why do hot particles become less dense? How does heat radiation travel? Can heat radiation travel through a vacuum?

Heat Transfer L/O :- To use your knowledge of conduction, convection and radiation, to explain the design of different objects Can you use what you know??

What is the difference between these 2 elephants? Can you explain this using conduction, convection or radiation? What is the difference between these 2 elephants? Can you explain this using conduction, convection or radiation? African Indian

End TASK There are a number of objects around the room. You are going to be asked to explain how each object uses CONDUCTION, CONVECTION and RADIATION You will need to fill out a sheet in pairs. You should take it in turns to fill out the sections. You will then be asked to feed your ideas back to other groups

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Survival Blanket Is it designed to keep heat in or let heat out? Does it use conduction? How? Does it use convection? How? Does it use radiation? How? Thermos Flask Is it designed to keep heat in or let heat out? Does it use conduction? How? Does it use convection? How? Does it use radiation? How?

Ray box Is it designed to keep heat in or let heat out? Does it use conduction? How? Does it use convection? How? Does it use radiation? How? Heat Sinks Is it designed to keep heat in or let heat out? Does it use conduction? How? Does it use convection? How? Does it use radiation? How?

Polystyrene Cups Is it designed to keep heat in or let heat out? Does it use conduction? How? Does it use convection? How? Does it use radiation? How? Radiometer Is it designed to attract heat or let heat out? Does it use conduction? How? Does it use convection? How? Does it use radiation? How?

Heat Transfer Questions 1.How does a non metal object slow down heat loss by conduction? 2.How does a material which traps tiny air pockets stop heat loss by 1.Conduction 2.Convection 3.How does a vacuum stop heat loss by 1.Conduction 2.Convection 4.How does a silvered surface stop heat loss by radiation?

How is this flask designed to prevent heat loss? The cork prevents heat being loss by convection Particles cannot leave out of the top and take heat with them Cork used as support and bung to prevent conduction. Cork has trapped air and so does not conduct well Vacuum to prevent conduction. There are no particles in a vacuum so no conduction can happen Silvered surfaces to slow radiation. The silver surfaces reflect heat back into the flask Would this keep a cold drink cold?

Why is it important for us to be able to save objects from losing energy? Energy costs a lot of money! Creating energy can release carbon dioxide which contributes to global warming Burning fossil fuels such as coal can release sulphur dioxide which causes acid rain Sometimes companies recycle their lost energy e.g. power stations can recycle some of the heat they produce to heat local homes. This is better for the environment and earns them extra money!

TASK Your task is to design the ‘snuggly-buggly’ ski-suit Use what you know about conduction, convection and radiation to design a suit to keep this baby as warm as possible. You will need to label your design to show what you features and materials you have chosen and why

What have you learnt? Can you explain how a thermos flask keeps your tea warm? Can you explain how an object would be designed to keep it as cool as possible e.g. a heat sink? Do you know what it is important to save energy/heat?