|OBJECTIVE||Learn the source for the earth's wind comes from the sun.|
|OVERVIEW||Using a toaster, the students will observe that wind is created by the rising heat.|
|TOTAL TIME||3 minutes|
|TEACHER PREPARATION||The hotter the toaster the better demonstration. Modern toasters have an automatic shutoff if they get too hot. If your toaster does not get hot enough then have the safety removed to enable it to remain on during the presentation.|
|SAFETY FOCUS||Thunderstorm Safety|
We feel the wind everyday. The air is almost always in motion. One day it may be from the north and the next day from the south. There are many sources for wind: mechanical sources such as fans and, in nature, falling rain as it drags air along. But what is the origin of wind on the earth?
- Turn the toaster on to allow the unit to heat.
- Ask the student where wind comes from.
- Ask the students if a toaster can create wind.
- Hold the pinwheel above (10-15 inches) the top of the toaster to allow the pinwheel to spin.
- Turn the toaster off.
Note: While hot plates and open flames will produce better results, the toaster is utilized to minimize fire risks should a student seek reproduce the experiment at home.
Most younger students will say clouds or trees cause the wind and that toasters cannot produce wind. They will quickly see that toasters do produce wind. Explain that wind is just air molecules in motion.
The glowing coils in the toaster produces infrared radiation, heating the toaster. The heated metal then warms the air in the toaster, making the air less dense, and therefore rises creating wind.
The source for the earth's heat is the sun. The radiation from the sun heats the ground. The ground, in turn, heats the air and as demonstrated, the air rises. As it rises, cooler air comes in to replace the rising air; what we feel as wind.
The faster the air rises, the faster the wind blows to take its place. Every time will feel the wind, regardless if is from the north, south, east, or west, somewhere else around the world the wind is rising. The term for this rising air is convection.
The wind patterns we experience have their source in convection.
It is the rising air that creates thunderstorms in the first place. When thunderstorms approach your first danger is generally lightning.
- REMEMBER that if you can hear thunder, you are close enough to a storm to be struck by lightning. Go to safe shelter immediately!
- Move to a sturdy building or car. Do not take shelter in small sheds, under isolated trees, or in convertible automobiles.
- If no shelter is nearby or available, get in a hard top car and keep the windows up.
- If you are boating or swimming, get out of boats and away from the water, get to land and find shelter immediately.
- If you are indoors, unplug unnecessary appliances and use the phone only for emergencies.