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Black Magic

검은색 펜에 숨겨져 있는 색깔을 찾아 봅니다.

scissors, white paper coffee filter, black marker (not permanent), water, coffee cup or mug

1. 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.)

2. With the black marker, draw a line across the circle, about 1 inch up from the bottom.

3. 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.

4. Watch as the water flows up the paper. When it touches the black line, you'll start to see some different colors.

5 . Leave the paper in the water until the colors go all the way to the top edge. How many colors can you see?

How does Black Magic work?
Why do some black inks separate into many colors on a wet coffee filter?

Most nonpermanent markers use inks that are made of colored pigments and water. On a coffee filter, the water in the ink carries the pigment onto the paper. When the ink dries, the pigment remains on the paper. When you dip the paper in water, the dried pigments dissolve. As the water travels up the paper, it carries the pigments along with it. Different-colored pigments are carried along at different rates; some travel farther and faster than others. How fast each pigment travels depends on the size of the pigment molecule and on how strongly the pigment is attracted to the paper. Since the water carries the different pigments at different rates, the black ink separates to reveal the colors that were mixed to make it. In this experiment, you're using a technique called chromatography. The name comes from the Greek words chroma and graph for "color writing." The technique was developed in 1910 by Russian botanist Mikhail Tsvet. He used it for separating the pigments that made up plant dyes. Your experiment flows through a stationary substance (like your coffee filter). Since different ingredients in a mixture are carried along at different rates, they end up in different places. By examining where all the ingredients ended up, scientists can figure out what was combined to make the mixture. Chromatography is one of the most valuable techniques biochemists have for separating mixtures. It can be used to determine the ingredients that make up a particular flavor or scent, to analyze the components of pollutants, to find traces of drugs in urine, and to separate blood proteins in various species of animals (a technique that's used to determine evolutionary relationships).

- 이 실험은 검은색 펜이 어떤 색들로 결합되어 있는지를 보여주는 실험입니다 . 이때 커피 필터는 물과 색소를 분리해 주는 역할을 해 주고 있습니다 .