Backpack Science is a summer series of easy at-home experiments geek dads can perform with their kids while school’s out. It is written by (San Francisco) Exploratorium science educator Ken Finn. This article is #2; you can find the whole series here.
Most people don’t realize there are colors hiding in black markers waiting to be discovered. After becoming adept at understanding the techniques in this experiment, my daughters investigated all the markers they could find to learn what the component colors might be. Now, when new markers show up at home, we like to “analyze” them with this project.
What you’ll need:
- white paper coffee filter
- black marker (not permanent)
- coffee cup or mug
How it’s done:
- Cut a circle out of the coffee filter. (It doesn’t have to be a perfect circle, just a round shape that’s about as big as your spread-out hand.)
- With the black marker, draw a line across the circle, about 1 inch up from the bottom.
- Put some water in the cup – enough to cover the bottom. Curl the paper circle so it fits inside the cup. Make sure the bottom of the circle is in the water.
- Watch as the water flows up the paper. When it touches the black line, you’ll start to see some different colors.
- Leave the paper in the water until the colors go all the way to the top edge. How many colors can you see?
- If you have another black marker, draw a line on a clean, dry coffee filter circle. Put the circle in some fresh water. Does this marker make different colors than the first one?
Black Magic, excerpted with permission from The Science Explorer, 1997, published by Exploratorium © Exploratorium, All Rights Reserved.