Jack O'Lantern Lava Lamp

CK librarians wanted to share this STEAM idea we found with you. You can find the original write-up on this website: Jack O'Lantern Lava Lamp. This is a fun, exciting and easy to do STEAM activity.

In my pictures I'm using a canning jar. You can easily use an empty spaghetti sauce jar to go bigger. Unfortunately, we had just recycled our spaghetti sauce jar from the week before.

This is a fun Halloween twist on a classic science experiment. It is not a true lava lamp, but rather a chemical reaction. The bubbles given off by the reaction create a really cool lava lamp effect!

The materials, listed below, are easy to get and you can repeat it over and over without making a mess or even having to refill the jar!

Supplies Needed for a Jack O’Lantern Lava Lamp

Clean empty jar – I used an 8oz mason canning jar, but you may want something bigger.

Red and yellow food coloring

Vegetable oil

Alka Seltzer tablets

Black felt

Hot glue gun (You can always use regular glue. If you use a glue gun, you can easily peel off the felt and use the jar in some other way later. You won't even be able to tell that the felt was there)

Step 01

Cut a Jack O’Lantern mouth and eyes out of black felt. Glue them to your jar with hot glue. If you are using a glue gun, make sure your parents are helping you!

Step 02

Fill your jar about 1/3 full with water. Add red and yellow food coloring to make the water orange.
It will take MUCH more yellow food coloring than red. If you add equal amounts, it will look red.

Step 03

Fill the jar the rest of the way with oil.
It will begin to settle and clear up after a minute or so.

Step 04

Drop in an Alka Seltzer tablet! The bubbles created by the Alka Seltzer dissolving in the water will float up through the oil, making a lava lamp effect.

Add more tablets!

As the bubbles die down, you can just drop in another Alka Seltzer tablet. You can probably go through at least 10 tablets without changing the water and oil.

The Science Behind the magic!

Alka Seltzer tablets contain sodium bicarbonate (baking soda), citric acid, and aspirin (a pain reliever). In the tablet, the baking soda and citric acid can’t react with each other. When you drop the tablets into water, the citric acid reacts with the baking soda to form sodium citrate (which neutralizes stomach acid when you drink it), water, and carbon dioxide bubbles. We’re just interested in the carbon dioxide bubbles because they form the cool lava lamp effect!

When you mix water and oil in your jar, the oil separates and rises to the top. Oil and water won’t mix since water is made up of polar molecules, or molecules that have uneven electrical charges, and oil is made up of non-polar molecules. Oil is also less dense than water, so the water sinks to the bottom and the oil ends up on top.

When you drop an Alka Seltzer into your lava lamp, it won’t react with the oil. It drops down to the water level and begins to bubble. The carbon dioxide bubbles rise up through the oil because they are lighter (less dense) than both water and oil, and they take some of the colored water along with them. Once the bubbles pop at the top, the colored water drops back down again.

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