Air Pressure and Wind
Discussion continued and information was given explaining how air pressure systems build and move. The ‘Air Pump' experiment encouraged students to explore and share ideas about high and low air pressure. Information was reinforced through a quiz on the internet.
Notes taken from : http://www.wxdude.com/basics.html
The wind blows because air has weight. Cold air weighs more than warm air, so the pressure of cold air is greater. When the sun warms the air, the air expands, gets lighter, and rises. Wind usually blows from areas of high air pressure to areas of low pressure.
High or Low
Although wind blows from areas of high pressure to areas of low pressure, it doesn't blow in a straight line. That's because the earth is rotating. In the northern hemisphere, the spin of the earth causes winds to curve to the right. This is called the coriolis force. So in the northern hemisphere, winds blow clockwise around an area of high pressure and counter-clockwise around low pressure.
The Weather Network
How Stuff Works
Air pressure Activity
Use a bicycle pump to show how air pressure makes wind. When you push down on the pump, the air pressure inside the pump is greater than the air pressure outside the pump. So the air flows from the high pressure inside the pump to the lower pressure outside. The harder you pump (or the greater the difference in air pressure), the faster the air blows out.
*Remember to link to review quiz. ;-)