Wind on Earth is caused by uneven heating of the planet's surface by the Sun. That's why it's so windy near the ocean; the land is heated by the sun and the ocean is less affected. The hot land radiates some of that heat out to the nearby air, making it become less dense and therefore rise up into the sky. The cooler air over the ocean rolls in to take the hot air's place.
I wanted to demonstrate this phenomenon at my weekly appearance for News Channel 10, so I made a little convection current box. It started with a drawing.
Then I glued together some acrylic sheets.
And here's the final product. Inside, I'm going to simulate a hot body of land near a cool body of water.
And here's how it works. Inside the larger chamber of the box, I place a cook-top element. The smaller reservoir gets filled with cold water. Dry ice is dumped into the water, creating fog, which makes the air currents visible. As the element gets hot, it causes the air above it to heat up and rise (remember, heating matter means the molecules spread apart and the volume increases while the mass of the air remains the same).
When the air over the element rises, cold air from the the other end of the box moves over to fill in the void. So, I've created a wind that moves from one end of the box to the other, all the time. In the photo above, you can barely make out a wisp of fog being "sucked" up into the center of the rising air column at the center of the heating element.
And a youtube video.
Howdy - hoping to get in touch with a question about the whispering dishes you made.
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