Ice and Oil Density Experiment for Valentine’s Day

If you are looking for fun Valentine STEM activities for a party or a special holiday-themed science center, you’ve found them! Making magic floating ice hearts is a fun and interesting way to demonstrate ice and oil density, to talk about density in general, and to learn about solubility. The adults will be just as interested as the kids as they watch what happens when the ice melts!

If you enjoy this Valentine’s Day science experiment and you are looking for more heart-filled fun, be sure to check out our ebook, 14 SUPER COOL VALENTINE’S DAY SCIENCE ACTIVITIES. It is jam-packed with bubbly, hands-on, colorful projects that are perfect for a Valentine’s Day party at home or at school. Click the picture below to find out more!

And be sure to scroll down to the end of this post for 24 MORE heart-themed learning activities for kids!

Getting Ready

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This is a very simple kitchen science experiment to set up. We already had everything we needed!

The day before I planned to do this ice and oil density experiment with the kids I made some heart-shaped ice cubes using these festive heart-shaped silicone ice cube trays. They work for so many different cool projects!

I dyed about 1/2 cup of water red with food coloring and poured the red water into the ice cube tray. The next morning we had delicate little red ice hearts.
When we were ready to begin I gathered the following supplies:

• Tall glass vase
• Water
• Vegetable oil
• Our red ice hearts

Ice and Oil Density Experiment

We have done many water and oil experiments so the kids are pretty familiar with what to expect. Over the years we have made lava lamps, experimented with food coloring bombs, and this past winter we even created a snowstorm in a jar with oil, water, and a few other ingredients.

They know that oil is less dense than water so it floats on the top. But what about ice?

The kids also know that ice is less dense than water from our many experiments. Fishing for ice, finding out how arctic animals stay warm, and making a fizzy color changing chemical reaction are just a few times they have seen ice float on top of water.

But what about ice and oil density? Which is less dense?

The kids were interested to find out.

Magic Floating Ice

We poured about 2 cups of water into the glass vase.

Then we added about 2 cups of vegetable oil.

The moment of truth finally arrived. It was time to add the ice.

We added a few ice hearts and noticed that they floated right in the middle of the oil. After a minute or so they settled toward the bottom of the oil layer. We guessed that the density of ice must be slightly more than that of vegetable oil.

As the ice melted, it was fascinating to watch the drops of water fall to the bottom of the vase. While ice may be slightly more dense than oil, liquid water is definitely much more dense than oil!

The liquid water droplets slowly let go of the ice heart, fell through the oil layer, and dissipated into the water.

There was so much anticipation watching as each droplet melted off the ice. The kids were absolutely mesmerized!

Ice and Oil Density Science Explained

It turns out that our observations about ice and oil density are backed up by actual measurements.

Density is a measure of the compactness of a substance, or how much mass of something you can fit into a given volume.

Here are the densities of the substances we used in this experiment:

Looking at this data, it makes perfect sense why we observed what we did!

The density of vegetable oil can vary based on its type. Our vegetable oil must have a density closer to 0.91 g/mL since the ice settled near the bottom of the oil layer. Your results may vary!

Liquid water is more dense than ice, so water droplets fall into the water layer one by one.

This is a wonderful STEM activity for kids to learn about density and solubility. Making a rainbow density jar is another wonderful way to demonstrate the principle of density!