Lava Lamp Lab

Lava Lamps are a fun and groovy lamp style that hit their peak popularity in the 1970's. They are famous for their mesmerizing and colorful bubble display that can be put right on your bedside table.

These colorful creations were invented in 1963 by Edward Craven-Walker, a British inventor (pictured on the right). They were inspired by an egg timer that he saw in a bar, and from then on out, they became instantly popular for their funky visuals and practical lighting. However, these lamps aren't just cool pieces of décor, but are actually made with some pretty cool science.

Real lava lamps use water and a special mixture of wax to create the floaty, lava like effect. The lightbulb at the bottom heats up the wax that floats around in the water, and this heating of the wax causes it to become less dense than the water. When things are less dense than the liquid they are contained in, they float! The hot wax floats up into the top of the container, where there is not a lightbulb. This means that it is cooler at the top of the lamp, and hotter the lower and closer to the lightbulb. The wax that floats to the top gradually cools down, and becomes denser. This causes it to float to the bottom of the lamp again. This continual heating and cooling is what causes the signature effect of a lava lamp.

Let's see if we can make our own!

What You'll Need:

• Water

• A clear plastic water bottle

• Vegetable oil

• Alka-Seltzer

• Food coloring

Experiment Steps:

1. Fill up the bottle with water about ¼ of the way

2. Fill the remainder of the bottle with vegetable oil

3. Wait a few minutes for the water and vegetable oil to separate

4. Put a few drops of your food coloring of choice into the bottle

5. Split the Alka-seltzer tab in half and put it into the bottle

6. Enjoy the show

If your lava lamp stops working, add another half tab of Alka-seltzer.

The lava lamps we made at home work just a little bit differently than the real deal, but the density science is still the same.

The oil is at the top of the bottle because it is light, and is less dense than the water. Since the food coloring has the same density as water, the food coloring also drops to the bottom and mixes together with the water. When you put the Alka-Seltzer into the bottle, gas is created. This gas brings the water with food coloring to the top of the bottle. When the bubbles reach the top, the air is let out, which causes the bubbles to drop back down to the bottom. The process is repeated until the Alka-Seltzer is gone.