lava lamp experiment with alka seltzer tablet

Lava lamp experiment

Looking for a fun and easy science experiment to do with your preschoolers? Try making lava lamps! All you need is mineral or vegetable oil, water, food coloring, and Alka-seltzer tablets for this fun homemade lava lamp.

lava lamp experiment with alka seltzer tablet

What is a homemade lava lamp?

This is an excellent activity for young scientists! Learn why we think science for kids is so important in this post.

Making a lava lamp experiment at home is a fun way to explore the chemical reaction of the sodium bicarbonate in the Alka-seltzer tablets as they interact with the water to make carbon dioxide gas. Since the water is denser than the oil, the water and oil won’t mix, leaving the colored water at the bottom of the container. And, because the food coloring only mixes with the water and not the oil, you can watch the bubbles carry colored water particles up the container before they pop and sink down again.

If you want to watch this lava lamp science experiment in action, check out this video by the Bearded Science Guy!

Download a scientific method worksheet before starting

This is totally optional, but you may want to head over to my TpT store and download the Scientific Method worksheet for free. This way, you can emphasize key learning moments while introducing your preschooler to the scientific method. By practicing this, they will become confident in their ability to hypothesize, test, and evaluate experiments!

Plus, if you write down the step-by-step instructions and tuck this away in a folder for later, they can re-create the same activity another time.

lava lamp experiment

How to create the lava lamp experiment

This simple project uses just a few household materials to create a beautiful science experiment. Follow the steps below to get started.

Here is everything you will need to make your own lava lamp at home:


  • 1 container
    • You can use a jar, bottle, glass, or even some recyclables. Whatever is on hand!
  • Water
  • Oil (mineral or vegetable oil)
  • Alka-seltzer tablets
    • You can find these near the denture cleaning section (by the toothbrushes and toothpaste) in any major grocery store or pharmacy
  • Your favorite food coloring color

That’s it! Make sure to follow the directions below carefully and you’ll be able to watch the lava lamp experiment in action!

top view of lava lamp experiment


  1. Fill a glass jar or bottle about 1/4 full with water.
  2. Add oil until the jar is almost full, leaving just a little bit of room at the top.
    • You can use either mineral oil or vegetable oil for this, whatever you have on hand! The only difference is that vegetable oil has a yellow tint (like in my photos above)
    • Since the denser liquid sinks, the oil floats and stays on the top
  3. Add a few drops of food coloring.
    • Ask your kiddos – What do you notice? Do the oil molecules and the water molecules mix? What about the color?
  4. Break up Alka-seltzer tablets in half to make this activity last longer
    • You can toss a full one in, but we actually started with quarters and it worked alright!
  5. Drop in an Alka-seltzer tablet and watch as the Alka-seltzer reacts with the water mixture!
    • The tablet will fizz the creation creates carbon dioxide, making the colored bubbles float to the surface. It makes a cool lava-like effect, much like the real lava lamps many of us grew up with.

Extending learning

In my opinion, most of the fun in science lies in observation! Once your kiddos have finished watching the colorful blobs float and pop, try asking them some questions like these to facilitate STEM-based conversations:

  • Why don’t the oil and the water mix?
  • What would happen if we put a whole Alka-seltzer tablet in?
  • Why do the bubbles pop?

These are just a few ideas to get their little minds thinking scientifically. You could also try experimenting with different types of oil, different colors, and different amounts of water and oil.


This fun experiment is one of my favorite science lessons because it’s quick and easy, and requires little materials! Children can begin to understand how different densities of liquids interact (oil and water) and can watch as the substances interact once the tablets are dropped in. They will love watching the bubbles attach themselves to the colored water during the chemical reaction created by the Alka-seltzer tablets.

Have you tried this lava lamp experiment at home? We would love to see how it turned out!

More science posts

Searching for more science experiments and science-related activities to do with your little ones? Check out this category to see all of our posts about science for kids!


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