Diffusion at Work!

Diffusion describes how things in nature spread from high concentration to low concentration. A better way of saying this is that freely moving particles in liquids and gases spread out to fill all the space available to them. One of the easiest ways to see diffusion work is through the use of dyes. Food coloring is a type of non-toxic dye. For our experiment, you'll want to get some red food coloring, a glass that you can see through, some water, and some white napkins or paper towels.

Ok, first of all, let's take a look at the food coloring. If your bottle of dye is made of see-through material, or if it has a clear dropper, you can look at the dye and see how dark red it is. If not, then take a drop and put it on one of your napkins.

Now take your cup and put some water in it, at least 4 oz. Look at the water closely. What do you see? You might see some tiny bubbles floating around, but other than that the cup should still be clear.

Now we are going to add some food coloring to the cup, one drop at a time. What do you think will happen when you add a drop to the cup? What will happen when you add two drops? What will happen when you add a lot of food coloring? Write down your what you think will happen, and be specific about it! This written statement will be your HYPOTHESIS. Scientists will make a hypothesis, and then see if it is true by experimenting!

Now add just ONE drop of food coloring to the cup. Watch what happens. Write down what you see. Now add another drop. Watch and write down what you see. Finally, add a third drop, and write down what you see. When you write down what you see, you are taking observations. These observations help you to describe what happens when you talk to other scientists.
Now add about seven or eight drops of food coloring to the cup, and carefully swirl the water in the cup. What happens?

Let's see what happens in the results Go back to the experiments! Go to the Neuse River introductory page


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