Sunday, 11 December 2011

The Air We Breathe


Saturday, 10 December 2011

Where Does It Rain ?

Listen a song.

Every day millions of tiny drops of water rise up into the air, from rivers and seas. When lots of these tiny drops of water float in the same part of the sky, they make a cloud. If tiny drops bum into each other, they mix together and become bigger drops. When these drops become heavy enough they fall back to Earth. We call this rain. In the country, rain soaks into the ground. In towns it goes down drains.  Eventually the rain runs back into the rivers and seas. It then rises again to the sky to make clouds.

Evaporation: Evaporation is when the sun heats up water in rivers or lakes or the ocean and turns it into vapor or steam. The water vapor or steam leaves the river, lake or ocean and goes into the air. 

Condensation: Water vapor in the air gets cold and changes back into liquid, forming clouds. This is called condensation. 

Precipitation: Precipitation occurs when so much water has condensed that the air cannot hold it anymore. The clouds get heavy and water falls back to the earth in the form of rain, hail, sleet or snow. 

Collection: When water falls back to earth as precipitation, it may fall back in the oceans, lakes or rivers or it may end up on land. When it ends up on land, it will either soak into the earth and become part of the “ground water” that plants and animals use to drink or it may run over the soil and collect in the oceans, lakes or rivers where the cycle starts all over again. 

Materials Of Things