Water and air around us · हमारे आस-पास पानी और हवा
A free Chemistry lesson for Class 6 children.
Water on Earth keeps moving in a cycle: it evaporates, forms clouds, falls as rain and flows back to the sea.
Too little rain for a long time causes drought. Too much rain causes floods.
We must save water: close taps, fix leaks, and collect rain water. This is rainwater harvesting.
Air is a mixture of gases. It is mostly nitrogen, about four-fifths, and oxygen, about one-fifth.
Air also has a little carbon dioxide, water vapour and dust.
Plants use carbon dioxide to make food and give out oxygen, which animals breathe. This keeps the balance of gases.