How to make your own lava lamp

This activity is part of our Science Lab series. Check out the ANU Science Lab for more experiments! In this activity, you will construct your own DIY lava lamp using simple household items to explore chemical reactions and liquid density. Watch the video above to see how it's done.

Lava lamp materials & ingredients

Fore each version of lamp lamp:

• A tall, clear glass or plastic container (about 500 mL capacity) 
• 100 mL water 
• 100 mL white vinegar 
• 200 mL cooking oil 
• 2 teaspoons bicarbonate of soda (baking soda) 
• A few drops of food coloring 
• Spoon 
• Measuring cup

Safety Note: Vinegar has a strong, sharp smell and food coloring can stain surfaces! It is best to set up this activity in a well-ventilated area or near an open window, and cover your workspace to protect against spills.

How to make a DIY lava lamp: step-by-step instructions

Method 1: The Classic Top-Down Lava Lamp

1. Add the Water Base: Pour 100 mL of water into your clear container until it is about a quarter full.
2. Add the Vinegar and Color: Pour in 100 mL of white vinegar so the container is now about half full. Add a few drops of food coloring and stir to mix it thoroughly.
3. Layer the Oil: Carefully pour 200 mL of cooking oil over the top until you have a thick layer floating above the colored liquid (roughly double the amount of water and vinegar combined). Allow the layers to separate completely.
4. Trigger the Reaction: Add 2 small teaspoons of bicarbonate of soda to the container and watch it sink through the oil layer to the bottom.

Method 2: The Bottom-Up Layering Method

1. Prepare the Base: Place 2 teaspoons of bicarbonate of soda at the bottom of a clear glass or cup.
2. Add the Oil Layer: Gently pour about 200 mL of cooking oil into the cup until it is about half full, taking care not to disturb the powder at the bottom too much.
3. Prepare the Colored Vinegar: In a separate small cup, mix roughly 100 mL of white vinegar (about half the volume of your oil) with a few drops of food coloring.
4. Start the Lava Lamp: Slowly pour the colored vinegar mixture directly into the oil cup and watch what happens as the liquid droplets sink through the oil to hit the base layer.

How does a lava lamp work? The science explained

Your DIY lava lamp operates using two fundamental scientific concepts: liquid density and an acid-base chemical reaction.

First, oil and water (or vinegar) have different densities and do not mix. Oil is non-polar or hydrophobic (water-fearing), so it separates and floats on top of the denser, water-based liquid.

Second, when the vinegar (an acid) comes into contact with the bicarbonate of soda (a base), a chemical reaction occurs that generates carbon dioxide gas.

• As carbon dioxide bubbles form at the bottom, they attach to droplets of the colored liquid.
• The gas bubbles lower the overall density of the colored droplets, causing them to float up through the oil layer to the top of the container.
• Once the bubbles reach the surface, they pop and release the carbon dioxide gas into the air.
• Without the gas to lift them, the dense colored liquid droplets sink back down to the bottom, creating the continuous lava lamp effect.

Science fair projects & taking it further: experimenting with variables

Experimenting with Variables Once you have made a basic lava lamp, try tweaking your setup to see how different variables change the speed, size, and shape of the bubbles:

• Container Shape: What happens if you use a very tall, skinny cylinder versus a wide dish? The shape changes how gas bubbles crowd together as they travel to the surface.
• Dilution with Water: What happens if you add more water to dilute the vinegar? Does the reaction speed up or slow down, and at what point does it stop bubbling?
• Temperature: Warmer liquids are generally less dense than colder liquids. Try using warm water or warm oil, or chilled liquids from the fridge, to see if temperature affects how fast the blobs rise and fall.