Have you ever seen a Lava Lamp and wondered how it worked? It’s all thanks to density!

Some liquids are denser than other liquids, which means they are heavier or contain more “”stuff” per unit volume. A Lava Lamp is filled with liquid and a layer of colored wax on the bottom. The light at the base of the lamp heats the wax. Drops of liquid wax are less dense than the liquid in the lamp. So, as the wax softens to liquid, it floats to the top of the lamp. When the wax cools and becomes solid again, it floats back to the bottom.

You can create a similar illusion using a few items from the kitchen.


Density's Dancing Drops Supplies

  • A tall, clear glass
  • Water
  • Cooking oil
  • Salt


  1. Fill your glass two-thirds full with water.
  2. Density's Dancing Drops 1

  3. Add enough oil to form about an inch thick layer. Since oil isn’t as dense as water, it will float to the top.
  4. Density's Dancing Drops 2

  5. Add some salt.
  6. Density's Dancing Drops 3

  7. Watch drops of oil dance in the water as the denser salt sinks and carries drops of oil with it. When the water dissolves the salt, the oil floats back up to the top again, like a Lava Lamp.
  8. Density's Dancing Drops 5

Originally written for and posted on the now-defunct My OH! Momma website.