chemistry
Candy Chromatography
Use forensic science to analyze different types of candy.
Materials
- At least two kinds of candy-coated sweets (like M&Ms, Reese’s Pieces, Skittles) in the same color (brown works best)
- Coffee filters cut into 1” x 3” strips
- Toothpicks
- Small glasses
- Water
- Pen
Directions
An adult should complete the first four steps without letting children see.
- Dampen an M&M and make a smudge on a coffee filter strip about a third of the way up.
- Poke a toothpick through the top of the filter paper. Rest the toothpick on the edge of an empty glass (or hold it) so the filter paper hangs down inside.
- Add enough water to the cup so that it touches the bottom of the crime scene filter paper but does NOT touch the candy smudge. Allow the water to rise up the filter paper, which causes the candy smudge to spread out. This will take a few minutes.
- Remove the filter paper from the water and allow it to dry.
Children can complete the following steps.
- Write “A” at the top of one of the unused filter papers and “B” at the top of another unused filter paper.
- Dampen an M&M and make a smudge on the “A” coffee filter strip about a third of the way up. Dampen the other candy (Reese’s Pieces, Skittles, etc.) and make a smudge on the “B” coffee filter strip about a third of the way up.
- Poke a toothpick through the top of the filter paper. Rest the toothpick on the edge of an empty glass so the filter paper hangs down inside. Repeat with the other filter paper.
- Add enough water to each cup so that it touches the bottom of the filter paper but does NOT touch the candy smudge. Allow the water to rise up the filter paper, which causes the candy smudge to spread out. This will take a few minutes.
- Remove the filter papers from the water and allow them to dry. Compare the “A” and “B” filter papers to the sample filter paper. Which type of candy matches the sample?
What's happening?
The dyes used to make colored candy can be made up of several colors. These dyes are composed of different compounds that separate during chromatography. The water rising up the filter paper caused the compounds in the candy to spread out in a spectrum.
Extension
Try this activity with different types of candy, or with candy of different colors. How are the results different?