The Amazing Water Experiment

My six year old did his first science fair experiment today. We are putting the project together for a science fair in March. It was fun, because he really didn't know what would happen. Here's his write up:

Introduction: My project is about me putting hot and cold water with food coloring. Why we did that was because we wanted to see if they would mix or not. And we figured out that they mixed when the cold water is on the top, but when the hot water was on the top, it did not mix. It stayed how it was.

What did you think would happen? The hot and cold water would mix.

Materials: We used two baby jars without the food in them, and we used a piece of wax paper, and hot water and cold water with food coloring in them.

Research: We found some different experiments on the Internet and we picked this one.

What did I do?
We put hot water in one jar and we put cold water in one jar. We put some food coloring in the water. We put red in the hot water, and we put blue in the cold water. We flipped the jar of cold water that was blue on top of the jar of hot water that was red. I pulled out the wax paper between the jars, and the water mixed and turned purple in both jars.

We did the same thing again, but we put the hot water that was red on top and it turned out to not mix. The red stayed red and the blue stayed blue.

What did I learn? That the cold water is heavier than the hot water, so the hot water could not go down into the cold water.

Awesome, isn't it?