Homeschool Science– Candy Colors

Whenever you eat a bag of M&Ms or Skittles, you may notice that there are several different colors of candies in each bag. On the back of each bag, you’ll also notice that many dyes are used to give color to the candies. In this homeschool science experiment, you’ll learn use chromatography to learn which dyes are used in which candy pieces.
To complete this experiment, you’ll need a few materials:
    •    One bag of M&Ms or Skittles (with at least one candy piece of each color)
    •    One coffee filter
    •    One tall glass
    •    Water
    •    Table salt
    •    A pencil (not a pen or a marker)
    •    Scissors
    •    One ruler
    •    Six toothpicks
    •    Aluminum foil
    •    One empty 2-liter bottle (with the cap)

After you have these materials gathered together, you’re ready to get going with the experiment. All set? If so, then proceed with the following steps:
    •    Cut the coffee filter into a 3x3 inch square.
    •    Draw a line on the coffee filter with a pencil about ½ an inch from the edge of the paper.
    •    Draw six dots on the paper with the pencil. The dots should be space equally on the line. Leave about ¼ of an inch between the first dot and the last dot on the edge of the paper.
    •    Just below the line, use your pencil to label each dot – one for each of the colors of candy. Y might represent yellow, for example.
    •    Once you have your paper ready, you’re all set to move on. Take an 8x4 inch piece of the foil and lay it flat on a table.
    •    Place six water droplets on the foil, spaced evenly apart.
    •    Put the candy on the foil – one color of candy for each of the drops of water.
    •    After about a minute, the color will have come off the candy and dissolved in the water. You can now remove the candies.
    •    Dip the tip of a toothpick into a colored water droplet. Touch it lightly to the coffee filter with the same color label.
    •    Repeat this process with each of your toothpicks and water drop colors.
    •    Once you have completed the process with all of the water droplets once, repeat the process again three times for each separate color. Wait for the colored spots to dry each time between adding the next drops of water.
    •    After the paper has dried, fold it in half. The paper should be able to stand up on its own vertically. Stand it up with the dots on the bottom of the paper.
    •    Now we’ll move onto the developing solution that you will need. Add 1/8 teaspoon of salt and three cups of water to the clean milk jug or soda bottle.
    •    Screw the cap back on the bottle and shake the bottle until the salt is dissolved in the water. This creates a 1% salt solution.
    •    Pour this salt solution into a glass until it is about ¼ inch high.
    •    Hold the filter paper in the glass solution so the dots are at the bottom of the glass.
    •    Record your observations as the salt solution begins to climb up the paper. (The salt solution is actually moving through the paper, not up. This is called a capillary action).

You probably noticed that as the salt solution climbed up the paper, some of the colors on the paper began to separate into different bands. This is because the colors in the candy are often made from more than one dye. The colors than are actually mixtures of different dyes will separate as the color bands move up the paper because some of the dyes will stick to the paper more while other dyes are more soluble in the salt solution. In the end, different dyes will have different levels on the paper.
By the way, you might want to download a free copy of the Homeschool Science Experiment Guide and workbook to find more great experiments.

You have just created a process called chromatography. You also created a mobile phase and a stationary phase. The mobile phase is the salt. The stationary phase is the paper. When you use the word “affinity” to refer to these phases, some dyes will have an affinity for the paper (stationary phase) and others will have an affinity for the salt (mobile phase).
You can perform this chromatography experiment with other colored products as well, including products made with Kool-Aid and food coloring. What other similarities and differences do you see in food colors with these other types of dyes? How does this homeschool science experiment help you to understand more about the content of coloring that we have in our foods?