Chromatography comes from the Greek ‘chroma’ and ‘graph’, literally ‘color writing’. It’s a method of separating mixtures out into their component parts. In this quick and easy experiment, we use chromatography to find out what colors make up black ink in a marker.
You’ll need a few simple items from the dollar store, but I bet most of you have these supplies at home already!
- coffee filters
- black marker
- cup or mug
Now, here’s the process:
- Cut a large circle about the size of your hand from the coffee filter.
- Take your black marker and draw a line across your coffee filter circle, about one inch up from the bottom.
- In your cup or mug, put just enough water to cover the bottom.
- Curl your coffee filter circle so it fits inside the cup or mug. Make sure the bottom of the filter is touching the water.
- Watch the marker line as the water begins to flow up the filter. As it rises, the different colors used in the ink should begin to separate out.
- Leave the filter in the cup until the water has reached the top. How many colors did your marker contain?
- Extension: Try different brands of markers. Are the colors the same?
- Extension: Instead of a line, draw a dot in the middle of your filter circle. Place the filter on a saucer and drip water onto the dot in the middle. What happens?
- Extension: Try it with different color markers!
This is not only a great STEM activity, but it also brings in Art to make STEAM! Dry out your filters and use them in a variety of art projects.