Lava Lamp Science Project

This lava lamp science project is one of the simple science experiments that’s perfect for middle school students.

With just a few simple materials, tweens can learn about density by creating their own lava lamp at home in less than 30 minutes.

While it might not quite be the lava lamp that was lighting up our bedrooms when we were kids, it’s still a hands-on way to learn about density.

Teen boys looking at a clear soda bottle with red liquid and vegetable oil inside - a DIY lava lamp.

This was a favorite science experiment of ours. Just drop the antacid tablet into the lava lamp mixture and watch as colored bubbles form to create hypnotic lava-like movements!

Lava Lamp Science Project

Kids of all ages will enjoy this science activity. Watching lava lamp bubbles rise and fall is captivating!

And not only are lava lamps cool to look at, they’re simple to make. Instead of relying on a heat source like an actual lava lamp, this project relies on a convection current.

That means that the liquids will rise and fall based on changes in their density.

It’s easy to do as part of your homeschool science. All you need is a tall clear plastic bottle, vegetable oil, water, food coloring, and Alka Seltzer tablets.

Keep reading for printable step-by-step instructions.

Household supplies used to make a lava lamp - empty bottles, vegetable and baby oil, effervescent tablets, and food coloring.

Science Behind Lava Lamp Experiment

This experiment is a great way to teach tweens about liquid density.

Kids will add oil, water, and food coloring to a bottle and then drop in a fizzy tablet.

The first thing tweens will notice is that the oil sits on top of the water, creating different layers. Because as you know, oil and water don’t mix. The oil floats on the surface of the water because it has a lower density than water.

Once added, the food coloring moves straight through the oil to the water because they have a similar density.

The alka-seltzer tablet is the heaviest, so it immediately sinks to the bottom of the container. As it dissolves, it releases carbon dioxide gas.

This is less dense than water or oil, so carbon dioxide gas bubbles float to the surface, taking along some of the coloured water molecules. That’s when you see the blobs of colored water.

Once the air escapes, the bubbles of carbon dioxide gas pop, releasing the colorful liquid.

Because of its higher density, the colorful liquid sink back down again.

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What You Need to Make a Lava Lamp

It’s always a plus when the supply list for a science experiment is short and includes items easily found around the house – like this fun science experiment!

Once you have your supplies, check out the easy instructions at the bottom of this post.

Empty Plastic BottlesEmpty Plastic BottlesEmpty Plastic BottlesVegetable OilVegetable OilVegetable OilFood ColoringFood ColoringFood ColoringAlka-Seltzer Effervescent TabletsAlka-Seltzer Effervescent TabletsAlka-Seltzer Effervescent Tablets


What can I use instead of Alka-Seltzer for a lava lamp?

Instead of relying on a tablet for the reaction you need for the lava lamp, you can use baking soda and vinegar to cause the chemical reaction to get the gas bubbles you need.

To make your lamp this way, first add a tablespoon of baking soda to the bottle. Then, add enough oil to fill the container about halfway. Pour some vinegar into a glass and add the food coloring to it.

Add the vinegar to the oil and baking soda mixture using a dropper.

Boy using a measuring cup to pour water into a clear bottle. Three images of DIY lava lamps with different colored liquid inside.

Tips for Modifying the Lava Lamp Science Experiment

As part of our science lesson, we created 3 different lava lamps, slightly altering the conditions each time.

Aside from replacing the tablet, here are some ways you can change the original experiment to test out different theories.

  • Use baby oil instead of vegetable oil
  • Combine the oils by using equal parts baby oil and vegetable oil
  • Change the amount of sodium bicarbonate you use – use more or less of the antacid tablets

Whenever you complete science projects with your homeschoolers, give them the opportunity to work through the scientific method.

This will let them change things up to see what happens and compare all the results.

Below you’ll find the experiment instructions.

Household supplies used to make a lava lamp - empty bottles, vegetable and baby oil, effervescent tablets, and food coloring.

More Science Activities

Ready to add more hands-on projects to your science lessons? Here are some easy experiments that use common household items.

Hopefully, this inspires you to make a DIY lava lamp with your tweens as you’re studying chemistry.

It’s such a fun hands-on activity that won’t take a lot of time and clearly shows the science of density for kids.

make a lava lamp

How To Make Your Own Lava Lamp

These are the steps to make your own homemade lava lamp. It's an easy science experiment to teach kids about different density of liquids.


  • Clear plastic bottle, glass mason jar, or tall clear glass
  • Vegetable Oil
  • Water
  • Food Coloring
  • Alka-Seltzer


  • Measuring Cup
  • Baking tray


    1. Place the bottle on top of a baking sheet to catch any spills.
    2. Fill the bottle halfway with oil.
    3. Add equal parts of water to the bottle. Make sure you stop at least an inch from the top.
    4. Add approximately 10 drops of food coloring.
    5. Cut or break the antacid tablet into quarters and drop one section into the bottle. When the bubbling slows, add another one of the small pieces to get the colorful blobs moving again.
    6. When you're finished, if you want to make the lava lamp bubble again later, wait until bubbles have completely dispersed and put on the cap. This will prevent gas from building up in the bottle.


Feel free to test out other types of oil to see if it changes the result.

Use more or less Alka-Seltzer to see what happens.

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Did you make this?

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Have you ever done this lava lamp experiment?

Megan Zechman
I love homeschooling! Learning is a way of life for our family. Most days you will find us exploring our Central Florida community, having fun while learning. I am constantly looking for new and interactive ways to engage my older children.
Megan Zechman
Megan Zechman
Megan Zechman

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  1. How cool! I will have to try this with my oldest daughter! She’s too old for so many projects, but I think she’ll find this really cool!

  2. Thanks for stopping by Shannen — I hope your daughter enjoys the lava lamp! My son has all 3 sitting on the shelf in his room now. These don’t light up, but he shines the flashlight through them to see if he can still get a similar look to a real lamp. It’s fun to find projects our older kids enjoy.

  3. I ove this idea! My high schooler would love to do it, and it would be a great break from her studies, it’s been a really busy year for her.

    1. Oh, what a great idea Bonnie! I might need to start saving some really fun bottles for my kids’ friends to share. Thanks for stopping by and for the idea 🙂

  4. Was there a difference in the baby oil or the vegetable oil? Did you prefer one over the other? Did one look better? Thanks.

  5. Great post, thank you! What were your results with the 3 separate tries- curious as to the baby oil in particular.

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