Northwest Arkansas Democrat-Gazette
• GREEN KIDS:
Wind = Air in Motion
Go outside and see if you can feel or see evidence of wind…which is air in motion! Try holding a blade of grass, a leaf, or a scarf. What happens when you let go? Is the wind blowing today? Did you feel the wind’s power? Wind helps plants grow by blowing seeds to new places. You can blow like the wind too! Can you pretend that your body is blowing in the wind? How does your movement change if the air is moving fast or slow?
Watching the wind
Build a mobile to help see the wind’s power. First, collect some natural items that you can hang. They can’t be too heavy. Try feathers, flowers, leaves. Now attach them with string to build a mobile. Hang them on a tree branch or somewhere else near your home where they can catch the wind. Now watch your mobile. Do you see the wind’s power to make your objects move?
Wind science
Wind is energy from moving air. Wind is caused by uneven heating of the earth’s surface by the sun. The earth’s surface is made up of different types of land and water, and they absorb the sun’s heat differently. During the day, air above the land heats up faster than air over water. Warm air over land expands and rises, and heavier, cooler air rushes in to take its place, creating wind. At night, the winds are reversed because air cools more rapidly over land than it does over water. In the same way, the atmospheric winds that circle the earth are created because the land near the earth’s equator is hotter than the land near the North Pole and the South Pole.
Harvesting wind energy
Wind has been used by humans for thousands of years for things like carrying ships, pumping water and grinding grain. Water-pumping windmills were once used throughout the United States and some still operate on farms and ranches, mainly to supply water for livestock. Wind energy can also be used to generate electricity. Wind turbines can catch the power of wind and turn it into electricity.
Hang a Clothes Line
One way that everyone in our world can use wind is to help dry our clothes! Try hanging a line outdoors so your family can dry clothes on it. (You could make your clothes line easily by hanging a rope between two trees or buildings.) It’s one of the cheapest and greenest ways to dry clothes and it uses no appliance or electricity at all. A simple clothes line and clothes pins cost very little. Using the heat of the sun and drying power of breezes, clotheslines dry your clothes without electricity. In most homes, a clothes dryer is typically the second- biggest electricity-using appliance after the refrigerator. In the United States, an electric dryer is expected to cost $1,530 US over the course of its expected lifetime of 18 years. Using wind power means we don’t need to use electric dryers, and that is good for the earth!
FUN FACTS ABOUT WIND
• Spiders are notorious wind travelers. They are able to use their silk as a simple parachute to carry them from one place to another. Here’s how it works: From the top of a platform (like a blade of grass), the spider faces the wind. Standing in a “tip-toe” position, with its abdomen pointing toward the sky, it releases a stream of silk from its spinneret. Lift off! The wind carries the spider through the air.
• Hundreds of species of
seeds travel and are spread by wind. Most commonly they are in the shape of a parachute, glider or helicopter. They have even been the inspiration for the design of early aircraft and gliders! Go to officialkidsmag.com to watch a video about seeds.
• Wind can change the shape of trees as they grow. Some are even called flag trees because the branches only grow on only one side of the tree.