Oil and Water Science Experiment for Kids: Easy & Fun STEM Activity

Want a fun and easy STEM activity for kids? Learn about density, polarity, and color mixing with this oil and water science experiment. Perfect for hands-on learning at home or in the classroom!

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As a kid, I thought science was boring. This makes my adult self so sad! Because as I’ve gotten older, I’ve realized that the problem was never science. The world is a fascinating, awe-inspiring place! The problem was that much of my science education was taught through books and worksheets that were disconnected from the wonders of the real world.

Now as an adult, I LOVE science, and I am determined to make science fun for my kids! How do I do that? I give them lots of hands-on opportunities to explore scientific principles in the world around them.

This oil and water science experiement is a fun and easy way to do exactly that! With just a few simple materials, your little scientists can observe how oil and water interact, mix colors, and explore the properties of liquids!

Why We Love This Experiment

Simple and Low-Prep: Uses common household items.
STEM Learning: Demonstrates chemistry ideas such as density, polarity, and immiscibility. (I just learned this term!)
Creative and Fun: Encourages artistic exploration with color mixing.
Engaging for All Ages: Perfect for preschoolers, elementary kids, and even curious tweens!

Ready to explore oil and water with your kids? Read the full tutorial below!

Oil and Water Science Experiment for Kids

Materials Needed:

A clear glass or plastic dish (like a baking dish)
Water
Clear/light-colored oil (baby oil works best, but you can also use canola or vegetable oil)
Food coloring or liquid watercolors
Pipettes or droppers (optional but highly recommended).*
Small cups for mixing colors
Paper towels for easy cleanup

*Note: You can use medicine droppers instead of pipettes, but it’s harder to control the flow of liquid from them. I recommend these inexpensive pipettes. We also love this set of sensory bin tools…and it has a sturdy zig-zag dropper (pictured) that is perfect for younger scientists.

Supplies needed to do an "Oil and Water Science Experiment" with kids. Colored water, clear oil (baby oil), droppers, clear glass dish (like a 9x13 pan).

Instructions:

1. Fill the dish with oil.
Pour a shallow layer of oil into your clear dish. This will be the base for your experiment.

2. Mix colored water.
In small cups, mix food coloring with water to create different vibrant colors.

3. Drop the colors in
Using pipettes or droppers, carefully drop colored water into the dish. Observe how the the drops form separate globs and don’t mix with the oil. Ask your child why they think this happens!

5. Observe & experiment
Encourage kids to experiment by adding more drops, mixing colors, or gently stirring to see what happens. What patterns do they create? What happens when they add more oil or water?

Want a fun STEM activity for kids? Learn about density, polarity, and color mixing with this fun oil and water science experiment!

The Science Behind It

This experiment demonstrates two important scientific concepts:

Polarity: Water molecules are polar, meaning they have a charge that allows them to mix with other polar substances (like food coloring). Oil molecules, however, are non-polar, so they repel water (also known as “hydrophobic”) and stay separate.
Density: If you add ENOUGH water, you’ll eventually notice that it sinks beneath the oil. Oil is less dense than water, so it floats on top.

Extend the Learning

Make Predictions: Ask kids what they think will happen before adding each element.
Try Different Liquids: Experiment with honey, milk, or soap to see how they interact with water and oil. This is fun to do in a tall jar or vase to make a density column.
Create an Oil and Water Lava Lamp: Do your experiment in a tall jar instead of a shallow pan, and add an effervescent tablet (like Alka-Seltzer) to create bubbling effects!

Tips to Manage the Mess

While this experiment is tons of fun, it can get a little messy! Here are some tips to keep cleanup easy:

Use a tray or plastic tablecloth to catch any spills. I have an old vinyl tablecloth that I use to cover our kitchen table any time we do art or science projects…and it makes clean up so much easier!
Wear old clothes or aprons to avoid stains from food coloring. I have some old t-shirts that I use as smocks for my kids. Cheap and easy!
Keep paper towels handy for quick cleanups.
Work near a sink for easy access to water when washing up.
Use washable, non-toxic food coloring to avoid permanent stains on hands or surfaces.

This oil and water experiment is a fun way to blend science and art for curious kids. It’s a perfect indoor activity for a rainy day, a homeschool STEM lesson, or a fun way to introduce basic chemistry at home.

Try it out!

Want more STEM activities for kids? Try these!