Chromatography
	Skills observing communicating comparing
	Materials (per group) strips of coffee filters black markers (not permanent markers) clear plastic cup water scissors tape ruler plastic straw optional: other colors of markers
	Doing the Activity Take a strip of coffee filter and with your black marker make a dot one inch from one end. Tape the other end of the coffee filter to the center of a straw. See picture. Put a small amount of water in the clear plastic cup. Place the straw over the plastic cup so that the coffee filter just touches the water. Don't let the dot go into the water. Observe what happens.
	Talking it over What happens as the coffee filter touches the water? What happens to the marker dot when the water reaches it? What do you see after the coffee filter has been in the water for a few minutes? What do you think would happen if we used a different color marker to make the dot? What do you think would happen if we used hot water? cold water?
	What's Happening The process of chromatography is used to separate things in a mixture. In this experiment, the colors move up the paper at different rates because they mix unevenly with water. Most colors are made up of other colors. You will probably be surprised to see the different colors that make up the original color. Scientists use chromatography to separate different chemicals.
	More Challenges Repeat the experiment using different colors of markers, different brands of markers, permanent markers and different temperatures of water. Create a chromatography picture. Take a whole coffee filter and decorate it with colored dots. Fold the co ffee filter in half and put the edge in a pan of water. Watch what happens.
	Activity Source Challenger Learning Center for Space Science Education. Revendezvous With Comet Hally, 1995.

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