Observations and results
Were you able to see wind make the cups on the anemometer spin around? Did the faster winds make the anemometer cups spin faster compared with the slower winds?
Because air is made up of tiny molecules, when wind hits something it is all of these molecules that are hitting the object. This is why when we feel wind we are really feeling these molecules hitting us. A faster wind hits us harder, and also moves the cups on the anemometer more, compared with a slower wind because the faster wind is moving the molecules at a faster speed. Consequently, in the same amount of time, a faster wind hits an object with more molecules than a slower wind does.
If you have been to the beach or near a large body of water, you may have noticed it is often windy. This is because there are different air pressures where a lot of water meets the land. Water takes more time to change its temperature compared with land, so during the day the land heats up faster, and once the sun goes down the land cools faster. Consequently, during the day there is wind blowing from the ocean to the land, or from an area of higher air pressure (colder air) to lower pressure (warmer air); in the evening the wind blows from the cold land to the warmer ocean.
More to explore
"Climate Change May Mean Slower Winds" from Scientific American
Web Weather for Kids from The University Corporation for Atmospheric Research (UCAR)
"Measuring Wind Speed" from Thirteen/WNET, Educational Broadcasting Corporation, New York
"Wind" from Weatherwizkids.com
Feel the Wind by Arthur Dorros
"How Does a Wind Meter Work?" from Science Buddies
This activity brought to you in partnership with Science Buddies and Cyberchase