How To Make a Safe Glowing Lava Lamp

Easy and Fun Glow in the Dark Lava Lamp

Close-up of colorful lava lamps
Steve Cicero / Getty Images

Use common household ingredients to make a safe lava lamp that glows in the dark. This is a variation on the popular oil and water lava lamp, except instead of coloring water with food coloring, you use a water-based liquid that glows.

Glowing Lava Lamp Materials

  • clear plastic bottle (a 20-ounce or 2-liter bottle works great)
  • vegetable oil
  • glowing water (or another glowing liquid)
  • Alka-Seltzer tablets
  • black light (may be optional, but even glowing liquids are brighter with one)

Whether the lava glows on its own or glows under a black light depends on the materials you choose. If you use glowing paint, expose the lava lamp to bright light, turn out the lights, and it will truly glow in the dark. However, the easiest and brightest liquid to use is glowing highlighter ink. If you aren't sure how to get the ink out of the highlighter, I have instructions. This ink (and your lava lamp) will glow when exposed to black or ultraviolet light.

What To Do

  1. Fill the bottle most of the way full with vegetable oil.
  2. Add a big spoonful of glowing water (or your glowing liquid of choice).
  3. Turn on the black light and dim the lights in the room.
  4. When you are ready for the lava to flow, break a seltzer tablet into pieces and add the pieces to the bottle.
  5. Cap the bottle and enjoy the 'magic'.
  6. You can recharge the lava lamp by adding more seltzer tablet chunks.

The Science Behind How It Works

The globules form because oil and water (or a water-based liquid) are immiscible. The oil has a nonpolar nature, while water is a polar molecule. No matter how much you shake the bottle, the two components will always separate.

The movement of the 'lava' is caused by the reaction between the seltzer tablets and water. Carbon dioxide gas forms bubbles, which rise to the top of the liquid and cause it to circulate.

The glow of the lava comes from either phosphorescence or fluorescence, depending on the chemical you used. Fluorescence occurs when a material absorbs energy and almost immediately releases light. A black light is used to make fluorescent materials keep glowing. Phosphorescence is a slower process in which energy is absorbed and released as light, so once a phosphorescent material is charged with light, it may continue to glow for several seconds, minutes, or even hours, depending on the specific chemicals.