Funny Money ~ Science Sunday

Question of the Week…What will happen to a quarter put on top of a soda bottle that has just come out of the freezer?

Items we used for this experiment:

~ 2 liter bottle

~ quarter

~ a little cold water

Predictions…

Each of the kids made a prediction about what they thought would happen to the quarter ~ would it fall in the bottle, fly off, jump around or just sit there and do nothing?

Predictions varied with all of the kids. Initially, the experiment called for using a nickel and the second I tried to rest the nickel on the top, it fell in {not because it was supposed to}. We quickly grabbed a quarter instead, and that worked much better.

The Experiment…

We left the 2 liter bottle in the freezer overnight {uncapped} and pulled it out to do the experiment. We used a little bit of cold water around the lip of the bottle and dipped our quarter in a glass of cold water and set it on top of the mouth of the bottle.

And then we watched and waited. And waited…..

Finally, the quarter started popping up and then would quickly drop back down onto the mouth of the bottle. {It’s here that I will insert that I was taking pictures like a madwoman trying to ‘catch’ the lift of the coin…to the tune of over 125 pictures of a soda bottle. Thank the Lord for digital cameras!}.

If you look REALLY close, you can see the picture lifting. I mean REALLY close.

The Nutshell Reason…

Temperature affects air pressure. As the air inside the bottle warmed up after it came out of the freezer, the air pressure increased. Cold air is more compact than warm air and as the air warms, the air particles push up on the quarter and try to escape the bottle.

Resource: How to Do Science Experiments with Children is available from Amazon and you can also check it out {and do some of the experiments} using Google Docs! The experiments use easy-to-find objects and also include record sheets for kids to fill out with their predictions and experiment results. Each experiment also includes teaching tips and explanations…which are rather handy! :) Don't forget to check out some other great science ideas at Science Sunday hosted by Ticia at Adventures in Mommydom.