Aiming to help children understand everyday objects and events around them, this book on finding out about energy is one of a series which introduces young readers to basic scientific concepts. The book contains activities so that the reader can test out the theories for themselves. The first activity is windmill making to learn how much better a windmill works on a windy day. It poses the question whether a small windmill works faster than a large one. Methods are given for making a water turbine using a large plastic bottle, a knitting needle and a cork. An experiment demonstrating the heating of water using solar panels is described. This activity establishes whether the water in a black panel heats better than a foil panel? Geothermal power is the use of natural heat from a source in the ground. To illustrate this children are asked to heat pebbles (with adult supervision) then to emerse them in cold water. The temperature of the cold water soon changes. Finally the book gives tips for the saving of energy.