Candy dye isn’t the only thing you can separate using chromatography. If you did our fall leaves chromatography, you are already an expert! If you missed it before, check out our previous chromatography experiment. This is a fun activity to keep in mind for the end of the summer: http://discoveryexpress.weebly.com/homeblog/is-a-black-marker-really-just-black-is-a-green-leaf-really-only-green-these-are-the-questions-well-answer-today-using-chromatography
Before we try our activity, let’s learn about what chromatography means.
Chromatography is a process in which a material is separated into its individual components. The word chromatography comes from two Greek words:
Chroma, “color,” and graphein, “to write.”
In the picture below, you can see that the original colors at the bottom of the paper have been separated into several different colors.
YOU WILL NEED:
- M&Ms or Skittles candies (1 of each color)
- Coffee filter paper
- A tall glass
- Table salt
- 6 toothpicks
- Aluminum foil
- 2 liter bottle with cap
Here’s what to do!
- Use the ruler to measure a 3 inch by 3 inch square of coffee filter paper and use the scissors to cut it out.
- Measure 1/2 inch up from the bottom edge of the paper and draw a horizontal line across the whole piece of paper.
- Starting from 1/4 inch in, make six dots equally spaced along the line. You should leave about 1/4 inch between the last dot and the edge of the paper.
- Below the horizontal line, label each dot with a color of candy that you have.
- Now you need to dissolve the dye off of the candy. Cut out an 8 inch by 4 inch piece of aluminum foil and lay it on a flat surface. Place one color of each candy on the foil. Make sure there is plenty of space between each piece.
- Carefully drop a bit of water on each piece of candy and wait for the color to dissolve into the water.
- Once the color is dissolved, carefully remove the candies and throw them away.
- Now you are going to transfer the dye onto the filter paper. Dip a toothpick into the red candy color and transfer it to the dot labeled red on the filter paper.
- Use a second toothpick to transfer the next color to its corresponding dot. Repeat until you have transferred each color to its dot on the filter paper.
- Wait until the dots have dried, and then repeat this process two more times to make sure you have transferred enough color for the experiment to work.
- Once the dots on the filter paper have dried, fold the paper in half so the fold is on the top and the dots are on the bottom.
- Next, you will make a developing solution out of water and salt. Add 1/8 teaspoon of salt and three cups of water to a clean 2 liter bottle. Screw the cap on and shake the bottle until the salt is completely dissolved.
- Pour 1/4 inch of the salt solution into a clear glass.
- Place the filter paper over the edge of the glass so that the very bottom of the paper touches the water but the dots stay above the water.
- Once you place the filter paper in the glass, you should see the water slowly climb up the filter paper. As the solution climbs, the color dots start to separate and move up the paper.
- When the salt solution has climbed to the top of the filter paper, remove the paper from the glass and lay it on a flat surface to dry.
- Once the filter paper has dried, analyze the results. Which dyes separated into more than one color? Did some stay the same? Which ones traveled the furthest?
Follow-up Questions: You may need to check your background information!
Why did some colors separate while others did not?
Did some colors travel farther than others? Why do you think this is?
In this experiment, what was the mobile phase and what was the stationary phase?
Experiment with different types of candy to see if they use the same dyes. For example, you could compare Skittles to M&Ms. Why would you do that? Some candies might contain different kinds of dye. A red M&M might have a different dye combination than a red Skittle. Try it out and record your observations.