Sunless Plant Experiment

Beans grown in the dark will behave differently than those grown in the light. Find out how with a sunless plant experiment.

What You'll Need:
  • Lima beans
  • Glass
  • Water
  • 2 plastic foam cups
  • Small rocks
  • Sand
  • Potting soil

Step 1: Soak six lima beans overnight in a glass of water.

Step 2: Take two plastic foam cups, and put about 1 inch of small rocks in the bottom of each one. Add 1 inch of sand to each cup, and then add about 4 inches of potting soil to each cup.

Step 3: Plant the six bean seeds, three in each cup. Water each cup to keep the soil moist but not wet.

Step 4: Put one cup on a sunny windowsill and the other in a dark closet. Check on your beans every day to see how they're growing. Are you surprised by the results?

What Happened? After several days, the plants growing on your windowsill will be healthy and green. The plants in the closet will be very pale, but they might be taller than the other plants.

Plant cells have special light receptors. When they don't get enough light, they signal the plant to grow long and thin to seek out a light source.

Since the light in the closet is limited, those plants don't produce chlorophyll, which makes plants green and absorbs sunlight to produce food. If you move the pale plants next to the green plants in the window, the pale plants will become green in time.

Read more science projects for kids: classifying plants to learn how you can grow flowers from your favorite vegetables.

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