Pockets of Air ~ Science Sunday

Question of the Week…Will a crumpled up napkin placed in the bottom of a cup get wet when the cup is placed upside down in a bowl of water?

Items we used for this experiment:

~ bowl

~ water

~ plastic cup {we used one we could see through}

~ napkin

Predictions and Experiment…

Each of the kids made a prediction about what they thought would happen to the napkin when we put it into the cup, turned it over and then pushed the cup down into the water. Would it get wet, stay dry, or suck up all the water?

After we’d made our predictions, we crumpled up the napkin and pushed it into the cup. Laurianna turned the cup upside down and carefully pushed it straight down into the bowl of water.

 

The napkin stayed dry! We tried the experiment again after we talked about the ‘why’ of the napkin staying dry {see below} and this time let the cup tip to the side when we put it in the water and the napkin got wet.

The Nutshell Reason…

Even though we can’t see it, air still takes up space. When we carefully put the cup into the the bowl of water, a pocket of air stayed kept the water from reaching the napkin. When we tipped the cup to the side and allowed the air to escape, the water pushed the air out and the napkin got wet.

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.