Everything on earth is made up of molecules. Even you! Molecules are super small, and we can’t see them, but trillions and trillions of them make up you, me and everything around us! And depending on how these tiny molecules are arranged in a space they form different types of matter.

Density is the amount of stuff or matter in a given amount of space. The higher the density, the more stuff in the space!

Weight or mass and density are about the same when objects are the same size. The more molecules in an object the heavier the object will be. We can tell if one object is denser and has more molecules than another object by its weight or mass.

In your lava lamp you’ll be exploring the densities of three different substances – oil, water, and carbon dioxide C02 to create what’s called a chemical reaction. This reaction takes place when two or more molecules join together or break apart. In its simplest terms a chemical reaction is when you mix two different things called reactants together to make something new called a product.

In this project you’ll mix baking soda and citric acid (reactants) to produce carbon dioxide (C02) and water (H20) (products).

The carbon dioxide gas bubbles that you created in your lava lamp are the product of a simple chemical reaction between baking soda and citric acid.

Required Materials

  • plastic bottle
  • food coloring
  • water
  • baking soda
  • citric acid
  • pipette
  • baby oil (any skin safe oil will work)
  • small cup

Step-By-Step Instructions

Step 1

Fill the bottle half-way full with baby oil. You will use the entire contents of your bottle.

Step 2

Fill the plastic cup with water and add two to three drops of food coloring.

Step 3

Fill the pipette with colored water.

Step 4

Drop the colored water from the pipette into the bottle.

Step 5

Pour the remaining colored water into the bottle. Leave about one inch unfilled.

Step 6

Carefully empty the contents of one baking soda & citric acid packet into the bottle. Watch the “lava” flow!

Step 7

Wait for the chemical reaction to finish before capping the bottle.