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Oil and Water Don’t Mix

10-15 Minutes: 2 and up: STEM
STEM Activities oil and water

Oil and Water Don't Mix

STEM Activities oil and water


This simple activity is sure to spark an interest in science for little ones! Children will marvel as they witness oil floating on top of water and discover what happens when they place drops of Liquid Watercolor into a cup of oil!

Set Up ideas

You may wish to set this activity up at a science center, have children gather around a table or provide children with their own cups to experiment on their own.

Let’s Get Started

For this colorful science activity, you'll need to gather clear plastic cups, Liquid Watercolor in various colors, vegetable oil and droppers to use with the Liquid Watercolor. Split the supplies needed by having children work in pairs together.


Provide each child with two cups: one with oil and one with water. Also provide each child with a container or cup of Liquid Watercolor.


Have children place drops of Liquid Watercolor into each cup. They'll discover that the water changes color, but the Liquid Watercolor just floats on top of the oil, which does not change.


Next, have the children place some oil and water into the same cup. They will observe that the oil floats to the top, resting just above the water. Have the child place a few drops of watercolor on the top and observe how the drops just sit on the top.


Children can then "magically" change the color of the water by putting some Liquid Watercolor into a dropper and releasing it underneath the oil. The water will change color while the oil does not.

Test children's reasoning and predictions skills by asking them how they think the Liquid Watercolor, oil and water will interact at each step. Before completing step 4, ask if they can figure out a way to change the color of the water, even with the oil sitting on top.


Tips and Tricks

Tips and Tricks

For this activity, it may be helpful if the children already have some experience with mixing colors or other materials in their science center.

Follow up Activity

Follow up Activity

Create an ocean in a bottle using what you've learned in this activity. Pour water, sequins, glitter and gems into a clear plastic bottle. Add oil, shake it up and watch as the mixture moves around.

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