We are on a roll this Valentine’s Day with holiday-themed science and STEM activities for kids. This week, we have been working on quick and easy Valentine’s Day science activities you can do right in the kitchen. This water displacement experiment is the perfect example of how just a few simple supplies provide a cool learning experience for kids.

Valentines Water Displacement Science Experiment and STEM ActivityPin

What Is Water Displacement?

When you put an object into water like our plastic love hearts below, it pushes water out of the way and takes the place of the water. We say that water displacement has occurred.

Volume is a measure of the amount of space an object takes up. The cool thing is we can measure the volume of the objects we have placed in the water by measuring the water displacement.

If you measure the amount the water level increases in your container, you can find the volume of the water pushed out of the way.

Here is an easy activity to introduce volume to young kids!

Water Displacement Experiment

The purpose of the experiment is to see if the same amount of hearts and liquid in different containers will rise the same amount. The parts that make this a good science experiment are the same amount of water in each container and the same number of hearts for each container. What’s different? The shape of the containers!

We used hearts for our Valentine’s Day experiment, but you could substitute them for any object you like.

Supplies:

  • 2 different size clear plastic containers {you can use more in varying sizes}
  • Package of red plastic hearts (for our Valentines theme)
  • 1 cup of water for each container
  • Plastic ruler
  • Sharpie
valentines Day water displacement set up and supplies usedPin

Instructions:

STEP 1: Make sure to have your kids predict what will happen to the level of the water before starting the experiment.

STEP 2: Measure 1 cup of water into each container being used.

STEP 3: Mark a line on the container with a sharpie to show the current level of the water.

Use a ruler to measure and record the height of the water.

STEP 4: Place a bowl of plastic hearts (or other small objects) next to the containers. We only had one bag of these. So we did one container at a time and then dried off our hearts to start again.

STEP 5: Begin dropping hearts into the water. Try not to splash water out of the container as this will alter the results a bit.

Valentines Day Water Displacement Science with plastic heartsPin

STEP 6: Once all hearts have been added, mark a new line for the new level of water.

Use the ruler again to measure the change in levels from the starting mark to the ending mark. Record your measurements.

Valentines Water Displacement science tall bottlePin

STEP 7: Dry the hearts and start over again with the next container.

Valentines water displacement measuring difference in water levelPin

Water Displacement For Younger Kids

We started this project as an activity. We had one cup with some water in it, not measured. I made a line with a marker, and we had a bowl of plastic hearts.

I had my son put the hearts into the water a few at a time. What did he notice? He discovered that the water rose above the line we marked. We made a new line. It’s pretty cool to find out that when we add an object to water, it causes water to rise!

Take a look at more science experiments with water here.

Talk about what happened. Were the predictions correct? Why or why not? What was different or the same between the containers?

You can measure and compare the containers’ results when your testing is complete. If you have an older child, you can set up a science experiment journal page to record your results and calculate the volume of water displacement.

More Fun Valentine’s Day Science Experiments

You can find all our Valentine’s Day science experiments here, including…

Printable Valentine STEM Project Pack

Countdown to Valentine’s Day with science and STEM! Pack includes complete instructions, templates, and images for 20+ activities. Bonus: printable science Valentine’s Day cards!