Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration. The movement is due to molecular collisions, which occur more frequently in areas of higher concentration.
Two or three glasses that are approximately 6.5 cm (approximately 2.5 in) in diameter and at least10 cm (4 in) tall.
Lemon or other light colored gelatin desert (example: Jell-O)
Ice water. This can be prepared by cooling water in a refrigerator or by putting ice cubes in water. The ice must be removed before using the water in the experiment below.
Effect of Temperature
1. Before you begin, read the experiment below and create a hypothesis regarding the rate of diffusion of food coloring in hot and cold water.
As the temperature of the water increases the diffusion rate decreases, therefore the food coloring in the hot water will diffuse faster than the food coloring in the cold water.
2. Add approximately 9 cm of very cold water (3.5 in) to one glass and 9 cm of very hot water to another.
Hot Cold Water Set Up
3. Place the glasses in a location where they can remain undisturbed. Allow the glasses to remain undisturbed for at least 2 minutes before proceeding to the next step.
4. Carefully place one small drop of food coloring on the surface of the water in the center of each glass. Care should be taken not to touch the glasses or disturb the water when adding the food coloring. The water should be as still as possible.
Hot Cold Water set up at 10 minutes
5. Observe the pattern of diffusion from the side. Do the glasses differ?
Yes, diffusion in cold water is slower and more concentrated. The hot water is more dispersed.
6. Estimate the percent of water in the glass that is covered every 30 seconds for 5 minutes. Initially (time = 0 sec.) there will be 0% colored. Round your answers to the nearest 10 percent (10%, 20%, 30%,...