Without pigments we’re nothing!

Paper Chromatography Student Instructions

  1. Grind, tear, and squeeze leaves until a liquid is obtained. (A little sand can make the grinding more efficient.) (Another way to do this is to lay the leaf over the chromatography paper and rub the leaf with the eraser of a pencil. The leaf tears, but if you keep going, you transfer enough chlorophyll to the paper to do the chromatography.).
  2. Being careful to touch the paper only on the edges, draw a faint line using a pencil across the narrow part of the paper, approximately 2 cm from the bottom. Use a coffee stirrer to place juice onto the chromatography paper strips 2 cm from bottom in the center. Place a drop on each strip, let it dry, and then add another drop until the spot is very dark.
  3. Add 15 mL alcohol to one drinking cup, 15 ml water to the other.
  4. Place paper clips through each strip towards the top at a height that will allow the bottom of the filter to just touch the alcohol and water without submerging the pigment spots. The paper clips can be clipped to a coffee stirrer and hung across the top of the cup. Do not let the spot wash off in the alcohol. The alcohol should be about 1 cm below the spot.
  5. Observe as alcohol and water rise through the strips, causing pigments to separate (approximately 15 minutes). Pull out the strips when the colors have stopped spreading or just before solvent reaches the top, and let them dry without touching them. Mark the position of the solvent front with a pencil. Mark with a small pencil line to one edge of the paper where the bands of color are. Draw in your notebook the chromatography paper noting any colors. Do this before the colors fade!

What colors do you see?

Why would leaves have so many different pigments?

How would it help photosynthesis?

A new planet was discovered. The sun is red. It is very hot and dry on the planet. Most of the sunlight that reaches the planet is red, orange, and yellow. Imagine that there is life on the planet. Draw a picture in the color of the imaginary plants on this alien planet. Then write a paragraph about why you imagined the plants looking as they do.