Make your own lava lamp using oil, food coloring and Alka Seltzer. This project is fun for kids and will make a great science fair project. How this works is explained after the instructions.
What you need:
Clear plastic bottle, any size (2-liter works best)
Oil (cooking or baby)
Alka Seltzer tablets
What to do:
Fill the bottle a little more than half full with oil. Fill the rest of the bottle with water, leaving about an inch or so at the top.
Wait about an hour for the water to settle at the bottom.
Squeeze about 10 drops of food coloring. Add glitter if you prefer.
Break the Alka Seltzer tables in 4 small pieces. Drop one at a time in the bottle and watch the fun happen.
Do over as many times as you want!
How it works:
Oil and water don’t mix because water is made up of millions and millions of molecules. Each molecule has a negative charge on one end and a positive charge on the other end. When a negative and positive charge are present, they stick together. These are called “polar molecules”. Oil is made up of millions and millions of molecules but the positive and negative charges are spread out more. These are called nonpolar molecules. Because the negative charges don’t have as many positive charges to connect to, the oil won’t stay stuck together when mixed causing the molecules to separate again. This is also the reason why you need to shake up the salad dressing before you use it.
The citric acid and sodium bicarbonate (baking soda) in the Alka Seltzer tablets are what causes the tablets to fizz. The air bubbles force the oil, water and food coloring to mix, but because the molecules in the solution will not mix with oil, the bubbles push the food coloring around, creating a pretty blob.