1In hot places the outer walls of houses are painted white. Why is that?
2Three tins of the same size, one white, one black and one golden, each with a thermometer in it, are left in the sunshine for the same length of time. Which thermometer shows the higher temperature, and why?
3What happens when a stone is dropped into the still water of a pond or a lake?
4What is the inner part of a thermos made of, and how does it work?
5Why do hot tea and cooked food become cold after some time?
6Why can the Sun's heat not reach us by conduction or by convection?
7Write the difference between a mechanical wave and an electromagnetic wave, with examples.
8What is the speed of sound in air, in water and in iron under ordinary conditions? What does this tell us?
9At what speed, and in how much time, do the light waves produced in the Sun reach the Earth?
10Why is it suitable to wear black or dark coloured clothes in cold places?
11How does a thermos block all three methods of heat transfer?