Lava lamps are always cool, but sometimes they’re a little pricey. These homemade lava lamps may not be exactly like the real thing, but they’re pretty close, and just as fun. This DIY is pretty simple, very cheap, you probably already have the supplies to do it.

What you’ll need:

1. Clear water bottle, or mason jar (which is what I used)
2. Food coloring
3. Vegetable oil
4. Alka-seltzer
5. Cup of water

Here’s how to do it :

1. Start by dropping food coloring into the cup of water – it doesn’t really matter how much food coloring you use, but just remember that the more food coloring you use, the darker the color will end up being.

2. Fill the mason jar (or water bottle) about  ¾ of the way with vegetable oil.

3. Add the colored water to the mason jar.

4. Crush a tab of Alka-seltzer and add a few pieces, one at a time, into your jar. (If you add all of the tab pieces at once, it will take away from the lava effect.)

You now have your very own lava lamp!

Disclaimer: This lava lamp only has a temporary reaction with the Alka-seltzer. It will not continuously run like a real lava lamp, but by simply adding a few pieces of the Alka-seltzer, it should continue to work well.