Creating a Vacuum Science Experiment

Kids think science is magical, and they love this Creating a Vacuum Science Experiment. It is so simple, but impossibly cool at the same time. How do you make water go up without touching it?

We tried this experiment a few years ago, and my girls loved it. They wanted to try it over and over again. This time was just as cool. It is bright and colorful, and anything that seems to defy gravity holds their interest.

This science experiment requires adult supervision. We don’t play with fire, but we can study it with the correct tools and helpers nearby. You could do this activity in a classroom or at home.

Creating a Vacuum Science Experiment:

1. Fill a glass or jar with water.
2. Add a few drops of food coloring to give the watercolor. This makes the project so much more visible and easier to observe as the change takes place.
3. Carefully place and light a candle in the center of a dish or plate. Make sure the plate has a bit of a lip or rises on the edges so the water won’t spill.
4. Pour the colored water around the candle.
5. Set an empty, clear glass over the top of the candle. Then wait a few seconds.

Isn’t that amazing! It is so fun to watch, and you can do it over and over again. Try experimenting with different-sized glasses or vases to get different water levels. Record the findings in an experiment journal.

Here’s how it works:

The flame from the candle quickly heats up the air in the glass. The hot air expands, forcing part of it out, underneath the edge of the glass.

When the flame goes out, the air abruptly cools again, and contracts. That contraction creates a vacuum, lower pressure inside the glass and higher pressure outside. The high outside pressure pushes water inside the glass until the pressure inside and and outside the glass are the same. When the pressure equalizes, the water level stops rising.

It’s that simple, and yet so neat to watch. Thank you for checking out this Creating a Vacuum Science Activity. Give it a try one afternoon, and get those little minds thinking and exploring the world around them.