Demonstrating that molecules of warm water moves faster than those of cold water.

You need two identical transparent containers. Put cold water in one container. Put the identical amount of warm water in the other. Place drops of food coloring in the cold water. Then put drops of food coloring in the warm.

Even with the addition of food coloring in the warm later than the cold water, you can witness the food coloring slowly dispersing in the cold water and quickly spreading in the warm water. This is a good demonstration.

Question: What causes the food coloring to spread through the water without stirring or shaking?
Answer: The movement of the water molecules

Question: Why does the food coloring mix faster in the warmer water?
Answer: The warmer the molecules are the faster they move. The quicker movement disperses the food coloring throughout faster.