Jon Chase explains the nuclear fusion that causes stars like our sun to give out enormous heat. Film footage of a nuclear explosion in a hydrogen bomb is used to draw an analogy with the sun’s energy. He mixes iron oxide and aluminum powder to demonstrate a highly exothermic chemical reaction and relates this to the much greater energy output of the sun. Teacher notes: Students could produce a poster on nuclear fusion in stars and compare with nuclear fission. This could also lead to an introduction to practical activity or demonstration of the Sun’s energy using a solar panel to produce electricity or to heat water. Students could undertake calculations using temperature and energy figures. Observe changes in the colour of metal as its temperature is increased from dull red to white.