Heavier Than Helium: All About Air
Fall is in the AIR in Pennsylvania! Even as we dodge the falling apples and wait to rake the falling leaves, we do try not to take that AIR for granted.
Let's grab a handful of air and talk about it. Of course since air is a gas we can easily decide on the amount of it we are going to examine. I usually find my cupped hands, although they look empty, will hold enough air to think about. Sometimes my young friends need to concentrate on a larger amount so we think about air by the roomful - choose the scale that suits you.
Now we can ask ourselves some questions and come back with our observations.
WHAT IS AIR MADE OF AND WHAT IS IN IT?
WHAT COLOR IS IT? HOW BIG IS IT? WHAT SHAPE IS IT?
WHAT IS PASSING THROUGH IT?
WHAT CAN AIR BE USED FOR?
Air is a mixture of gases; there is oxygen that our bodies need to work and grow, a lot of nitrogen and small amounts of other chemicals such as carbon dioxide.
Our discussions of what is in the air are wide-ranging and inventive. Your car needs washing just from standing on the street? Has anyone noticed the air changing when you breathe out on a cold, cold morning? Ozone? Pollution? Douglas has tried but never been able to catch the dust specks he sees in a shaft of sunlight. Kevin does not appreciate pollen but understands why the flowers like it. Thomas explains that there are also viruses in the air.
It seems to me that air is invisible, but is that always so? Can you ever see the color of air? Yes, the runaway favorite color of the air is a rainbow when we can find one. Look at the ABOUT RAINBOWS page for an explanation. Any other suggestions?
The answer to the size question is surely "Air is as big as it wants to be, it's humongous!" Now the scientist in us wonders HOW BIG IS THAT? Any suggestions? We have an opinion that air most resembles a giant skin wrapped all around the Earth, always rushing to fill any big or tiny space it can find.
We have thought about things IN the air but now, what about anything else that may be passing THROUGH the air?
Try the following experiments using the scientist's primary tools. Have everyone be very quiet and concentrate on listening. During the listening each child can quietly describe one of the sounds reaching their ears. The list will grow quickly as those sound vibrations come PASSING THROUGH the air around them. Repeat the experiment observing any smells that reach their noses. Chalk? Flowers? Smoke? Someone baking an apple pie? Add smelling as well as listening to the experiment - chalk? grass? flowers? smoke?
We can go on discussing sights we see, radios we listen to, walkie-talkies, lasers, X-rays and so on. Just imagine how magical it is to have this happening in one small handful (or roomful) of AIR! No wonder the ancient alchemists decided it must be a basic element!
The USES of air are countless and my friend Jordan's answer is immediate and best - BREATHING.
We consider many air-driven machines and decide our favorite is the Hovercraft. Imagine having one vehicle you can use to ride over roads, rivers, fields, beaches, seas without ever leaving your seat; that is the Hovercraft. SIMON'S HOVERCRAFT DESIGN page describes how it can be done and has pictures from races.
AN EXPERIMENT TO SHOW THE STRENGTH OF AIR
Lay a round balloon on a table with the "spout" hanging over the table edge. Place a pencil on each opposite side of the balloon. Lay a book across the pencils and over the un-inflated balloon. Now blow into the balloon and watch the strength of the "squashed" air as it gradually raises that book off the table.
To make this experiment more "scientific" take a few more steps:
1. Gather predictions as to HOW BIG a pile of
books could be lifted by this method.
2. Gradually add more books to the pile until inflating the balloon no longer lifts it.
3. Remove books from the stack, one by one, until the stack is again "liftable."
4. Compare your prediction with the actual result.
Our first grade experiment, using this procedure, showed that while predictions ranged from 13 to 25 books taken from our reading corner bookshelf, in fact we were able to raise a stack of 41 books by blowing into that small balloon.
Then we begin IMAGINING. What if you took four balloons, bigger than ours and with thicker skins, wrapped them around wheels, attached an axle to each pair of wheels and then squashed a lot of air into each of the "tires".....? Then what could the air hold up?
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