Sun, wind and water at work

Your book shows that the Sun, the wind and flowing water can make things work — without plugging anything in. Three activities show it, and your book tells us what happened in each.

A paper pinwheel held in the wind spins round. Sunlight focused through a magnifying glass onto paper makes the paper burn (this must only be done with an adult). And water poured onto a wheel made from a paper cup and five spoons makes the wheel spin. The pinwheel rotated, the paper burned and the water wheel spun: the wind, the Sun and water are sources of energy.

We use them every day. People dry papads and clothes in the sunlight. Long ago, ships with huge sails used wind energy to cross the seas: traders from places like Gujarat and Tamil Nadu sailed to Africa, Arabia and Southeast Asia using the power of the wind.

In hilly areas, watermills called gharaats use flowing water to grind grain.