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General Chemistry Science Fair Project

Alka-Seltzer Lava Lamp

Alka-Seltzer Lava Lamp | Science Fair Projects | STEM Projects
Prepare for a mind-blowing experience as gas changes the density of water, making it float or sink in oil. Watch the captivating dance of colorful blobs and learn about density and gas properties.


The hypothesis is that adding gas to water will change its density, causing it to float or sink in oil.

Method & Materials

You will fill a bottle with oil and add water and food coloring. Then, drop an Alka-Seltzer tablet and observe the mesmerizing dance of colorful blobs.
You will need Alka-Seltzer or a similar effervescent tablet, vegetable oil, water, a tall clear plastic container, food coloring.


When the Alka-Seltzer tablet bubbles, the water and gas mixture floats up through the oil in a ball-shape, creating colorful blobs. As the gas bubbles pop at the top, the water sinks back down through the oil, completing the cycle. This project demonstrates the concept of density and how gas affects the buoyancy of objects.

Why do this project?

This science project is fascinating because it combines density and properties of liquid and gases in a visually captivating way. The dancing blobs of color in the homemade lava lamp make learning about science fun and exciting.

Also Consider

Vary the amount of Alka-Seltzer tablet to observe the effect on the movement of blobs. Try using different types of liquids, such as carbonated water or vinegar, instead of plain water, and compare the results.

Full project details

You can find additional information and details for this science fair project here. Have fun exploring!

Related videos

Hey there! Here are some awesome videos about this science project that we think you'll really like. They're not only super fun, but they'll also help you learn more about the science behind the project. So sit back, relax, and get ready to have some fun!!
Follow along with the Cincinnati Museum Center in making an Alka-Seltzer lava lamp! Learn about density of water and oil, and the chemical reaction that happens when an Alka-Seltzer tablet is dropped in!
Find out why the colored water moves up and down in the lava lamp experiment!
Check out this close up video of colored water blobs moving up and down the lava lamp!
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