Lava lamps are fun! They’re very colorful and bright. A lot of people like to use it as a night light. People, especially kids, can do a science experiment and create their own lava lamp using bottle, oil, water, food coloring, and Alka-seltzer. It’s really easy and it will explain science to kids in a fun way!

Materials:

Bottle
Vegetable Oil
Water
Funnel (optional)
Alka-seltzer Food coloring (color of your choice)
Flashlight (optional)

Step 1: Fill Most of the Bottle With Vegetable Oil.

Get your bottle and fill the bottle with vegetable oil leaving approximately a quarter empty. There’s no exact measuring on how much you have to put in your bottle as different sizes of bottles may vary. You can use a funnel to pour your oil so it’s not messy.

Step 2: Fill the Rest of the Bottle With Water.

Fill your bottle with water leaving just about a third of the bottle empty. For an easier pour, you can use a funnel to prevent any spilling. Adding water to your bottle is one of the most important steps for your lava lamp.

Water and oil don’t mix together because the oil is lighter than the water. Since the water is more dense, it will sink to the bottom of the bottle. Water and oil don’t mix together because of “intermolecular polarity” which basically means that water molecules are attracted to water molecules and oil molecules are attracted to oil molecules. Adding oil and water together will make the “bubbles” in your lava lamp with your Alka-Seltzer in the next step. Carbon Dioxide gas will be produced from the reaction of the Alka-Seltzer tablet reacting to the water. The temperature of the water will affect its density. The hotter the water, the less dense it will be.

A little tip, using hot water is better than cold or room temperature water and you’ll see why in a bit.

Step 3: Add a Few Drops of Food Coloring.

Take a food coloring of your choice and add a few drops of food coloring into your mixture of oil and water. Adding food coloring is basically adding more fun to your lava lamp. The amount of food coloring you put in your bottle depends on your preference and how big your bottle is.

From my experiment, I added roughly 7 drops of food coloring. You don't want to put a lot because it might just make your whole "mixture" of oil and water the same color but you also don't want to put less because you might not be able to see the color that you want your lava lamp to be.

Step 4: Break an Alka-Seltzer in Half.

Break your Alka-seltzer in half. After breaking the Alka-seltzer in half, drop it in your bottle of oil, water, and food coloring. Adding an Alka-Seltzer to your bottle makes everything bubble. This is due to the fact that Alka-Seltzer is both acidic and basic. Tablets contain sodium bicarbonate (a base) and citric acid, therefore starts dissolving and creating a gas.

Because of the gas that the Alka-Seltzer made, the bubbles took the colored water with it. The bubble then reaches the top of the bottle.

So, from what I’ve stated in Step 2, using hot water is better than using cold or room temperature water. This is because using hot water will produce more bubbles in your lava lamp. Since the hot water has a higher temperature, its molecules move faster than cold or room temperature water.

Step 5: Add the Other Half to Keep the Effect Going.

At some point, the fizz from the first half of your Alka-seltzer will stop. In order for your lava lamp to continue its effect, add the other half of the Alka-seltzer.

Step 6: Enjoy!

Use a flashlight to have that real lava lamp effect. Having the cap on or off shouldn’t make any difference with your lava lamp. Just keep adding more Alka-seltzer if you want your lava lamp to continue. Use different colors in different bottles so you can have a variety of colorful lava lamps!

For my experiment, I did two different bottles (however, I didn't show the second bottle I made) to see why you have to specifically use a vegetable oil. In my first bottle, I used vegetable oil (the picture in the first step) which turned out really well. In my second bottle, I used extra virgin olive oil. I wouldn't recommend using extra virgin olive oil. Because the oil is too dark, you wouldn't be able to see the fizz from the Alka-Seltzer and the food coloring.

In the video, I've used the other half of the Alka-Seltzer (I forgot to record dropping the first half of the Alka-Seltzer. I got excited). That's why before I dropped the Alka-Seltzer, there was already bubbles on top and the oil and water have some color.