Easy Oil and Water Science Experiment for Kids

I got my six-year-old a little test tube and dropper set for Christmas (ours came from the Target dollar section but there are lots of fun ones on Amazon), so naturally, she was desperate for me to come up with a science experiment that we could do to try out her new equipment.  Fortunately, I remember this easy oil and water science experiment, and it was perfect!

DISCLOSURE: THIS POST MAY CONTAIN AFFILIATE LINKS, MEANING I GET A COMMISSION IF YOU DECIDE TO MAKE A PURCHASE THROUGH MY LINKS, AT NO COST TO YOU. PLEASE READ MY TERMS OF USE POLICY FOR MORE INFO.

The best part of this experiment is that it looks SO COOL.  The little bubbles that the oil makes inside the water remind me of the lava lamp I had in the 90s! (Did I just age myself?!)

And I love the fact that this science investigation is appropriate for kids of all ages.  If your little one can hold and use a dropper, they’re ready to try this activity!  My two-year-old participated by squeezing colored water into cups, and she was thrilled.  My six-year-old was fascinated by the colorful bubbles and couldn’t get enough of this activity.  And older kids would love this one, too!

If you’re looking for more STEM-based play ideas, be sure to check out this guide to making ice cream in a bag, this one all about how to make slime, and this fizzy heart STEM activity.

Want to learn to incorporate more sensory play into your day?  I created this free guide just for you!

Materials Needed

We were excited to use our science equipment for this experiment, but realistically, you don’t need anything fancy – you probably already have everything you need in your kitchen!  

• Clear jars and/or cups – I used mason jars
• Water
• Food coloring
• Oil (vegetable oil is nice and cheap!)
• Spoon or stirrer (optional)
• Dropper or pipette

Performing the Experiment

This oil and water experiment really couldn’t be much simpler!  I filled two mason jars about half full with water, and added different colors of food coloring to each (we did one red and one blue). 

I set out two more mason jars about half full of vegetable oil , as well as two droppers and a spoon.

I encouraged my six-year-old, Ella, to slowly squeeze a few drops of colored water into the oil. You may want to model this part to begin with.

We observed what happened, and oohed and ahhed at the colorful bubbles that formed inside the oil.

Ella experimented with big drops of water and small drops, as well as squeezing in one drop at a time versus several drops in a row. 

While Ella investigated the oil and water, two-year-old Ruthie was thrilled to have a cup of water and a dropper that I kept filling for her so she could squeeze the water back into the cup!

The Science Behind It

There are a couple of science principles at work here that make this oil and water activity as cool as it is.  The first is density – water is denser than oil, which is why the water bubbles sink to the bottom of the cup.

The second one is immiscibility – this just means that oil and water do not mix due to their molecular structures.

I kept the conversation pretty light, mostly just asking leading questions, such as “Why do you think the water isn’t mixing all the way into the oil?”.  And I briefly mentioned and explained the concept of density, but I didn’t worry too much about whether Ella retained the new vocabulary word or not.

Learning Benefits

This super simple activity has so many learning benefits!  By simply playing with some basic household items, your child will develop observation and prediction skills and be introduced to foundational science concepts such as density and immiscibility.

This experiment can also double as a sensory activity, too!  Using different colors and watching how bubbles form inside the oil creates a soothing visual experience.  And you can allow your little one to dip their fingers in the water and then the oil, and notice the very different consistencies of the two liquids.

And (maybe most importantly), this science investigation encourages hands-on exploration and curiosity – by playing with oil and water, your child is growing the passion to become a life-long learner!

Notes & Helpful Hints

As with any science investigation, adult supervision is recommended.  Also, you may want to lay down a towel under the area where your child will be working – depending on how much free reign you give your kiddo, this activity can get a bit messy.

Use this activity as a conversation starter about other liquids and their properties.  Which liquids mix, and which don’t?  Does oil react the same way in a cup of soda that it does in a cup of water?

And encourage your kiddos to ask questions and share their observations.  The more conversations you have surrounding this activity, the more children will learn!

This activity really is so simple but SO cool.  I can’t wait for you to try it!  And when you do, I would love to hear what you think!

Comment below or message me on Instagram and tell me whether your little one enjoyed this activity!