1. Week 11
Lesson 4
Presentation 4

2. Objectives
Be able to describe how thermal radiation is controlled in everyday circumstances
Explain how a vacuum flask can minimise all types of heat transfer
Use ideas of heat transfer to design a house that is energy-efficient

3. In very hot countries, people paint their buildings white
In very hot countries, people paint their buildings white. Why do they do this?
Try to explain using the idea of thermal radiation

4. After exercising for a long time your body can cool down very quickly when you stop.
Long distance runners are given a silver ‘space blanket’.
Why is it silver?
Again, use the idea of Thermal Radiation to explain

5. During re-entry to the atmosphere the bottom of the Space Shuttle gets very hot.
Why is it painted black?

6. What features does a vacuum flask have that stop all 3 types of heat transfer; Conduction, Convection and Radiation?

7. Slows down heat loss by radiation
Stops heat leaving by convection to the open air
Stops heat leaving by conduction because there are no particles to conduct
Stopper
Vacuum between
inner and outer wall
Silvered inner and
outer wall

8. The Eco-House
Design a house that will be as energy-efficient as possible.
Use the ideas that we have learnt on different types of heat transfer (conduction, convection and radiation)
Try to think of some natural materials that can be used instead of artificial ones.
E.g. Soil makes a very good insulator!!