Your littles will soon be hypnotized watching the bubbles rise through the oil in this beautiful lava lamp. If they want to enjoy their lamp after dark, drop in a glow stick, switch off the lights, and they will have an even more magical experience.
A glass tumbler
Vegetable oil (you will need quite a lot)
A clear plastic bottle
Alka-Seltzer tablets (or fizzing Vitamin C tablets)
A glow stick (optional)
1. Before you start making your lava lamp, have a bit of fun investigating oil and water. Fill a glass with water and then drop in a teaspoon of oil. Watch what happens to the oil. Stir it hard to mix it into the water and then wait and watch!
2. Now to make your lamp. Using the funnel, pour water into the bottle until it is about a quarter full.
3. Using the funnel again, pour in the vegetable oil until the bottle is a bit more than three-quarters full. You need to leave room for your glow stick.
4. Watch as the oil and water separate into two layers with the heavier water sitting at the bottom. Wait until the oil and water have settled.
5. Add about 12 drops of food colouring. Watch as it falls through the oil—the coloring will not mix with the oil. It will fall until it meets the water and will then sit on top of the water for a few seconds before bursting into the water and then spreading out in the water. Gently twist the bottle a few times to help the colour mix with the water, but don’t stir or shake it.
6. Now, break an Alka-Seltzer (or fizzing Vitamin C) tablet into about 4 smaller pieces. Drop one piece of the tablet into the bottle. It will drop through the oil into the water and begin to fizz. Watch as bubbles begin to erupt through the oil. When the bubbling begins to slow down, add another piece of Alka-Seltzer and it will start all over again.
7. For the full glow show, bend your glow stick to activate it, drop it into the bottle, and switch off the lights.
Oil and water don’t mix and oil floats on top of water. This is because oil is less dense than water. When you drop the piece of Alka-Seltzer into the lava lamp bottle it drops through the oil and into the water. Here it begins to fizz, releasing small bubbles of carbon dioxide. These bubbles get attached to blobs of water and act like floats. The blobs rise up to the surface through the oil. When they reach the surface, the gas escapes and without its float to hold it up, the more dense water sinks back down.