AUSTIN, Texas - Making your own lava lamp is fun, easy, and a great way to view substances with different densities interacting with each other.
Here’s what you’ll need:
- A clear glass or container
- Vegetable oil
- Food coloring
- Alka-seltzer tablets
Fill your container up a quarter of the way with water.
Add enough vegetable oil to almost fill the container up, leaving some room between the top of the oil and the top of the container. Now add about 10 drops of food coloring. The drops will sink down to the water and eventually mix in.
The oil and the water don’t mix because of something called intermolecular polarity. Essentially the water molecules are attracted to the water molecules and the oil molecules are attracted to the oil molecules. At a molecular level, the two substances don’t bond. The oil sits atop the water because the oil is less dense than the water.
After you add the food coloring, break an Alka Seltzer tablet into quarters and drop them into the container. What happens after the tablet sinks to the bottom
When the Alka Seltzer hits the water, it creates a reaction that produces carbon dioxide gas. The carbon dioxide gas bubbles are less dense than the oil and water so they rise to the top. As they rise, a bit of colored water rises with the bubble, through the oil.
This creates the lava lamp effect.
Once the carbon dioxide bubble reaches the surface, the CO2 gas escapes, and the water droplet, which is denser than the oil, is left behind to sink back down to the bottom. The process will repeat itself over and over until the Alka Seltzer tablet dissolves.
When you’re out of Alka Seltzer tablets, you can set the oil/water mixture aside with a lid on it. Whenever you want to create the lava lamp effect again, just add more Alka Seltzer.