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Our Blanket of Air
Thomas Jefferson Elementary
School, Academic Year 2011-2012
Grade 2 |
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Dr. DeLeo came into our classrooms to describe the Earth's atmosphere, our wonderful and life-giving blanket of air. He talked to us about what happens as we go higher and higher. We all knew that the air gets thinner and thinner until it is so thin that you can't even breathe. In fact, if you go up high enough, you are in outer space and there isn't any air at all. The photo on the left shows the Earth from about 200 miles up (NASA). Notice the thin blanket of air that surrounds the Earth.
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| We talked about the highest place on Earth, Mount Everest. At the top, about 5 miles up, the air is so thin that you need to use oxygen masks most of the time. The photo just to the right shows Mount Everest, and the one on the far right shows what it looks like from the top. |
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Photos above from http://erigreste.files.wordpress.com/2008/11/everest_west_view.jpg (left photo, 4/25/11) and http://www.project-himalaya.com/dispatches/2006/i06-everest/88a-summit-pan.jpg (right photo, 4/25/11) |
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Since Weather is one of the science units we are studying this year, we talked next about what happens when air is heated up. Many of us already knew that hot air rises, and cooler air falls. Weather patterns on Earth are driven by this effect as the sun heats the Earth's surface and the air above it. Dr. DeLeo demonstrated that hot air rises by placing a spiral piece of paper above a hot light bulb. The rising hot air pushed on the paper and made it spin. |
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Dr. DeLeo told us that our blanket of air pushes on us; it exerts a force on us (and everything) of about 15 pounds on every one-inch square. That's like the weight of 3 bags of sugar pushing on each square inch of our body! We don't get crushed because there is an equal force pushing from the inside out as well. Remembering that a force is a push or a pull, we demonstrated how two forces can be in balance, like in the photo on the left. However, if one hand, say the left hand, pushes harder, both hands - and anything in between - will move to the right.
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| Dr. DeLeo demonstrated the effect by dropping some lit matches into a flask (a special bottle) and then placing a hard-boiled egg on top of the opening. This is shown in the eight photos, starting from the one on the far left and continuing below (they are numbered). |
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Dr. DeLeo explained that when air is heated, it expands and takes up more space. (Since each volume of air is now lighter, that's why hot air rises.) When the match goes out, the air cools and pulls in (it contracts, the opposite of expands). As the air pulls in, it sucks in the egg. Looked at another way, the force of the air pushing the egg from the outside down into the bottle is greater than the force of the air inside the bottle pushing up, so the egg gets pushed in! Dr. DeLeo showed us that when he blows into the bottle, the air goes around the egg to the other side, and pushes it out - almost into his mouth! |
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| On the far left is a VIDEO of the egg sliding into the bottle. And, just to the left is a VIDEO of a larger egg going into an iced tea bottle that is too small! What a mess! Just click on the play buttons to see the videos. |
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Click the play button on the photo on the right to see a VIDEO of Dr. DeLeo blowing into the bottle to get the egg out. |
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For our final adventure, Dr. DeLeo brought in a box with a large hole in one end, and a smaller hole in the other. The large hole was covered with a clear plastic shower-curtain liner. When you wacked the plastic with your hand, a ring of air, called a ring vortex, came out the other end. You can see it blowing a student's hair in the photos below. |
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| The photos to the left and below show Dr. DeLeo using the ring-vortex box to put out candles that we were holding! |
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| Mrs. Unger was taking pictures of us when the candle flame blew out. She must be a really great photographer, because, as you can see on the right, she got a photo of the candle flame as it was being blown away from the wick of the candle! |
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Dr. DeLeo brought a fog maker, like the kind they use in movies to make fake fog. Now we could really see the rings of air! He aimed them at the ceiling so we could see the rings more clearly. |
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Below are some more photo sequences showing ring vortexes. The last one shows a close-up of the ring. |
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And then he aimed the fog rings at us!! It was so funny that we couldn't stop laughing. We didn't want him to stop. |
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And to the left is a VIDEO showing a ring vortex.
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At the end of the program, Dr. DeLeo gave each of us a placemat about weather. We had lots of fun! |
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I hope you have enjoyed this web presentation as much as we enjoyed sharing the actual learning experience with your son or daughter. Although we have endeavored to exclude photographs where permission has been denied, it is possible for errors to occur. If you would like us to remove a photograph of your son or daughter for any reason, please send me an e-mail message at lgd0@lehigh.edu or call me at 610-758-3413, and we will remove it promptly. Please note that we will never associate a child's full or last name with a photograph except in circumstances where special permission was explicitly provided. Thank you. Gary DeLeo. |
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