Ask Dr. Universe: Why does the wind blow?

Dr. Universe: Why does the wind blow? – Odin, 7, Mount Vernon, Washington

Dear Odin,

When the wind blows, it can do all kinds of things. It can help pick up tiny seeds and carry them away so plants and flowers can grow in new places. It can push a big sailboat across an ocean. We can even harness the wind to make clean energy to power our homes and schools.

That’s what I found out from my friend Gordon Taub, an engineer at Washington State University. He is very curious about wind energy and told me more about why the wind blows.

Whether it’s a breeze, a gust or a gale, winds are blowing in our atmosphere all the time. When the sun heats the Earth, it doesn’t actually heat the Earth evenly. Part of the reason the Earth doesn’t heat up evenly is that the sun is really far away.

Because the Earth is a big sphere, when the sun’s rays finally get to us, they are going mainly in one direction. They are mainly pointed at the Earth’s equator. That means rays have to travel farther to get to the ground at the poles than they do at the equator. As the sun’s rays pass through the air, they get weaker.

When the air at the equator warms up, it expands, Taub reminded me. Things start cycling around as warm air moves in to places where there is cooler air. It is this mixing and movement of air at different temperatures and pressures that gives us our winds.

The wind holds a lot of energy, too. Wind turbines can help take the kinetic or motion energy of wind and turn it into electrical energy that can power our world.

Taub’s students are actually working on a wind turbine project of their own this year and will debut it at a national competition. If you are curious about wind, maybe one day you’ll join students at WSU to investigate wind power, too.

Maybe you’ve also seen some wind turbines if you’ve traveled across our state. Taub said wind turbines usually start spinning when the wind is blowing about 11 mph They usually shut down when winds reach speeds of about 44 mph so the blades don’t get busted up.

You know, we have some pretty strong winds on Earth, but that’s nothing compared to other planets. Jupiter’s red spot has winds of up to 250 mph, almost twice the speed of the fastest wind on Earth (163 mph was the highest recorded). And Neptune’s winds are the fastest in the solar system, reaching 1,600 mph – even faster than a fighter jet.

On earth, wind also can help us stay cool on hot days. I think I’m going to make my very own wind-powered pinwheel this summer. You can try to make one of your own, too. We’ll need some scissors, paper, a wooden stick and a brass fastener. Search YouTube for “Pinwheel DIY” to find instructions and then watch your creation spin in the wind.

Sincerely,

Dr. Universe