COLOUR SPLASH Let’s find out about whether or not water and oil mix by using food colouring

Materials Needed 3 clear plastic cups water cooking oil liquid food coloring pencil

Instructions Fill one cup about 2/3 full of water and another about 2/3 full of oil. Add a few drops of food coloring to each cup. Leave space between the drops so they don't touch. What happens? Fill the third cup about 2/3 full of water. Pour in enough cooking oil so it forms a thin layer on top of the water. What do you think will happen if you add food coloring to this last cup? Make a prediction and then test it out. Touch one of the drops of food coloring in the last cup with the tip of a pencil. What happens?

What did it look like when we were doing this experiment?

So what did we discover? Here's why this works. When you add food coloring to water, it mixes in. When you add food colouring to oil, it stays in a little ball and does not mix in. Why? Food colouring is mostly made of water, and water and oil don't mix. Even if you stir them, the oil separates and forms a layer on top of the water. So when you add food coloring to the cup that has water and oil, each drop is coated with oil. That is why the drops sit in the oil layer. The oil is like a raft that helps the food coloring float. If you poke a drop with a pencil, the oil layer is broken. Then the food coloring mixes with the water and makes a cool design.

We also made a LAVA LAMP… Make Your Own Lava Lamp Here’s what you’ll need: Bottle, Vegetable Oil, Water, Food Colouring, Alka-Seltzer (or any effervescent antacid)   Here’s what you’ll do: 1. Fill the bottle ¾ of the way with vegetable oil. 2. Use water to fill the bottle the remainder of the way, just below the bottle’s neck. 3. Place 10 drops of food coloring into the bottle. 4. Break the Alka-Seltzer into four pieces. Place one piece in after the other until all have been added. 5. Place the cap on the bottle. Now watch what happens—you have a lava lamp! What’s happening: This experiment proves that water and oil don’t mix. The carbon dioxide gas created when you dropped the pieces of Alka-Seltzer tables into the mixture causes the coloured water blobs to push to the top through the oil.