Hosted from Elimbah, Queensland Australia. Wind is caused by pressure differences in the atmosphere, or the difference in the mass of air in different places. Where the pressure is high the air will move outwards to an area where the pressure is lower. If you have a bicycle pump, as you push the handle inwards, you increase the pressure in the body of the pump and air is pushed out through the hole in the bottom to the lower pressure outside the body of the pump.
Hot air is lighter than cold air, and tends to rise upwards, lowering the pressure underneath.
Air moves towards this lower pressure to try to make the pressures the same. Ross Evans 2. As the very small drops of water in the clouds move around, they bump into each other and join together and become bigger. After enough have joined together they become too heavy and fall back to earth, they are now rain drops. Hold a cool mirror or smooth metal plate above a pot of boiling water, some of the steam will condense on the surface.