Preschool Science: Learning about Air

A couple days ago, the girls (3 years old) and I did some science experiments to learn about the properties of air.  They were inspired by both Building Foundations for Scientific Understanding (BFSU) and the book Science in Seconds for Kids by Jean Potter (which contains over 100 experiments that have very little setup time).  Here are the four experiments we did...

We made a balloon-propelled rocket by threading a toilet paper tube on a piece of string and taping a balloon to it.  The girls laughed hysterically when they let go of the balloon and watched it launch across the room.  We also did a few (ok, a lot of) rounds just blowing up the balloon (without the toilet paper roll) and watching it shoot across the room.  They have a pretty good grasp of the basics behind the science of what is going on (if I ask them what's inside the balloon they say 'air', and can describe how the balloon stretches as it is filled with air and then the air needs to escape through a small opening).

Next I asked the girls if they think the balloon could fill up with air all by itself..  I explained that when air gets hot, the particles move around very fast and bump into each other (we ran around the room and demonstrated), and when they get cold they stand still and shiver (we demonstrated that too).  I put the balloon around the opening of an empty soda bottle and boiled some water in the microwave.  The girls observed the bubbles that we coming up from the boiling water.  We then plunged the bottle into the hot water to see what would happen:

L and E watched excitedly as the balloon began to fill up with the expanding hot air.  Then we put it into a cup of cold water and watched the balloon deflate.

The kids asked me to repeat this experiment over and over.  When I removed the bottle from the hot water, I observed that it had shrunk considerably, and let the girls compare the size of the bottle with its original size:

For our next experiment, I asked the girls what would happen to paper if we put it in water (it would get wet), and then told them that I knew a trick for keeping paper dry in water.  First, L crumpled up a piece of paper and stuffed it into a cup.  Then I showed her how to plunge the cup straight down into the water without tipping it (she then did it herself). 

L examined the paper and found that it was dry!  We repeated the experiment, but this time tipping the cup, and observed air bubbles coming out and water coming in (producing a wet piece of paper).  I let both girls play with bottles in their pans of water, watching the air bubbles come out when they tipped them:

For our final demonstration, I showed L how to hold a cup full of water upside down without spilling it (E was still playing with her water and wasn't interested):

All you have to do is fill a plastic cup with water all the way to the rim and place a piece of paper or index card over it.  As long as the water forms a good seal, the air pressure will allow you to flip the cup over without releasing the water.  By the way - ignore the dirty dishes in the sink in the above photo - at our house, science comes before dishes (although my husband may disagree)...

We probably didn't need to do so many experiments to demonstrate the properties of air, but it was so much fun that we just kept going and going all afternoon, and the kids even continued the experimentation as they took a bath!

I know that these experiments made an impression on them because a couple days later, E asked me if I remembered when we inflated the balloon by putting it in hot water, and proceeded to describe the experiments and results to me, completely on her own.

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