Lava Lamp Experiment

A classic decor item for any groovy home, this lava lamp experiment will show kids how to produce their own lamps- no heat required.

What You Will Need

– three empty water bottles
– food coloring
– vegetable oil
– Alka-Seltzer tablets

What You Will Do

Fill each bottle just over half full with oil, then fill the rest with water, leaving an inch open at the top. Add about 10 drops of food coloring.

Break an Alka-Seltzer tablet into four pieces and drop them into the bottle one piece at a time. Go slowly and wait for each piece to stop bubbling before adding more. Adding them too fast will make your solution cloudy.

Put the cap on your bottle, turn it around a few times, and watch the magic of your new lava lamp in action!

For a video of this process, check out this link.

What is Going On?

There are two main scientific principles going on here: density and polarity.

Density is the measure of how much of a substance can fit in a defined space, in other words how compact it is.

Polarity comes from lopsided electrical charges in substances that cause them to either attract or repel each other. Water molecules are ‘polar’, because one end of the molecule is positively charged while the other end is negatively charged. The positive ends of water molecules will bind with negative ends of other molecules and vice verses.

Oil molecules are nonpolar, meaning that the oil isn’t attracted to water and consequently won’t mix with it. That’s why the layers in your lava lamp stay separate!

Instead of using light like real lava lamps, this homemade version relies on Alka-Seltzer to power the reaction. When the Alka-Seltzer goes in the water, it reacts to produce carbon dioxide gas bubbles that stick to the water droplets. These droplets are less dense than the oil, so they rise to the top of the water bottle where they pop and release the gas. The now denser water droplets then fall back to the bottom to repeat the process.

Want a kit that makes this even easier? Get it here: