What other kinds of energy can we use? You have seen in the previous question the stages through which the Sun’s energy passes before we can tap it as the fossil fuel, petrol. It has taken millions of years for the world’s reserves of oil to be built up and we have consumed much of it in a few decades. We need energy in our homes and in industry and for...

How does the Sun power a Racing Car? A racing car as you know has a petrol-driven engine. The petrol is a fossil fuel ultimately depending on the Sun’s energy, as we shall see. On a sunny day you can feel the Sun’s rays warming your face. The Sun is applying energy in the form of heat. Solid as it may look, the Sun is completely made up of gas, so...

How do we know what the bottoms of oceans are like? Over two-thirds of the Earth’s surface is covered with water. Most of this is very deep and we call it ocean. People cannot go down very far because the pressure of the water on them increases the deeper they go. Deep-sea divers wear protective clothing to stop their bodies being crushed. However, people have gone down to great depths using...

Why do we build dams? Man-made dams are large walls built across rivers or lakes so that the water builds up on one side of them. The water can be let out of the dams if required. Dams are useful to us in many ways. We need water to drink and to grow our food but in many parts of the world, at different times, there is sometimes too much water...

Can water climb?   Water usually flows downwards, pulled by the force of gravity. However, in certain circumstances, it can move upwards or climb! If you place a thick and a thin plastic straw in a beaker of coloured Water, the water will rise up the straws above the level of the water in the beaker. The water will rise further up the thin straw than the thick straw. The ability...