Kids Science Experiments

Upside Down Water

This is a great excuse to spill your cup. Let's see what happens to water when we turn a cup upside down.

Our Science Experiment

We are going to turn a cup half full of water upside down.

What you need

a clear plastic cup
water
a note card big enough to fit over the whole top of the cup

How to perform this experiment

Fill your cup a little less than 1/2 full with water. Hold the cup over a sink and slowly turn it over. The water pours out into the sink! Refill your cup with water again and place the card on top of the cup (make sure you cover the top completely). Press down firmly on the card and tip your cup upside down again over the sink. Count to three slowly and then remove your hand.

Watch!

The water stays in the cup with the card over it. Eventually, the water will trickle out, the seal will break, and all the water will fall.

Why did it do that?

Air pressure below the cup pushes up on the card.

I wonder what would happen if

I wonder what would happen if I added a small ice cube to the water?