Making Water Spill {Water Cohesion} ~ Science Sunday

This week we did a pretty simple experiment, but one that ALL of the kids enjoyed being a part of {even Kaleb}.

It involved two of their favorite things: money and water. What’s not to like about that, eh?

 

Question of the Week…

How many pennies would it take to make the water spill over the top of the bowl?

Items we used for this experiment:

~ a bowl

~ water

~ lots of pennies

Predictions and Experiment…

Each of the kids made a prediction that underestimated what actually took place. :) They had to guess how many pennies we would be able to drop in an already full bowl of water. Each of them figured under 10…when in reality it was almost 40 pennies!

We divided out a pile of pennies and the kids each took a turn dropping a penny into the bowl of water.

and dropping…

Can you see the water bulging over the top? Ours bulged even more than this before it started spilling.

 

The Nutshell Reason…

The water molecules are attracted to each other {cohesion}. Cohesion keeps liquids from spreading out {gas will spread, liquids stick together}. A dome will form on the top of the water as the water rises higher because the water molecules are pulled inward {toward the center} of the water mass.

As pennies are added the water starts to rise due to cohesion. The water will eventually spill when gravity kicks in.

After the Experiment…

While we talked about the ‘why’ behind the experiment that we did, the kids illustrated their version of the experiment on the back side of their experiment sheets. Later we answered a few questions together about the experiment.

And then fought about who got to keep the pennies…{sigh}.

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.