Indoor activity
DIY Lava Lamp
Watch colourful blobs rise and fall like magic in your very own lava lamp — powered by science!
Materials
- Effervescent Tablet
- Flashlight optional
- Food Colouring
- Glass Jar
- Vegetable Oil
Illustrated Steps
Fill the Jar with Oil
Pour vegetable oil into a glass jar until three-quarters full. Notice how thick and slow-moving it is compared to water.
Add Coloured Water
Mix food colouring into a small cup of water and gently pour it into the jar. Watch it sink straight through the oil!
Drop in the Tablet
Break an effervescent tablet into pieces and drop one in. Coloured blobs rise and fall as gas bubbles carry them through the oil.
Light It Up
Shine a flashlight under the jar in a dark room. The glowing, coloured blobs look just like a real lava lamp!
What You’ll Create
A mesmerising lava lamp in a jar! Coloured water droplets rise and fall through oil in a continuous bubbling display, just like the iconic lamps from the 1970s — made at home with things from your kitchen.
How to Set It Up
Step 1: Fill the Jar with Oil
Pour vegetable oil into a clear glass jar until it is about three-quarters full. Notice how thick and slow-moving the oil is compared to water.
Step 2: Add Coloured Water
Mix a few drops of food colouring into a small cup of water. Gently pour the coloured water into the jar. Watch it sink straight through the oil — they don’t mix!
Step 3: Drop in the Tablet
Break an effervescent tablet into 3–4 pieces. Drop one piece in and watch the fizzing begin! Coloured blobs rise and fall through the oil as bubbles push them up and down.
Step 4: Light It Up
Hold a flashlight under the jar in a darkened room. The coloured blobs will glow and sparkle — just like a real lava lamp!
Have fun!
Keep dropping tablet pieces to keep the show going. Try different food colouring colours, or mix two colours for a tie-dye effect. How long can you keep it going with just one tablet?
Why It’s Amazing
Oil and water don’t mix because they have different densities and molecular structures. The effervescent tablet reacts with the water to make carbon dioxide gas bubbles. These bubbles attach to coloured water droplets and float them up through the oil. At the top the bubbles pop, and the water sinks back down — and the cycle repeats!
Pro Tips
💡 Use a tall narrow jar for the best effect. 💡 Baby oil gives an even clearer result than vegetable oil. 💡 If the reaction slows down, drop in another piece of tablet.