The Tickle Plant

• This plant reacts to touch.Jupiterimages/Photos.com/Getty Images
  
  You can "tickle" a Mimosa pudica plant and watch it move in reaction to you. Record the plant's reactions as you touch it in different ways, such as with your finger, your breath, an ice cube, a toothpick or your hair. How long does it take to recover after being touched? Does the plant demonstrate "sleep" behavior?
  
  

Upside Down Plant

• Plants always grow toward the sky.Comstock Images/Comstock/Getty Images
  
  Tropism is a plant's growth movement toward a positive stimulus or away from a negative stimulus. Gravitropism, also called geotropism, causes the plant to grow toward the sky, even if it is upside down. Gravity causes the plant hormone auxin to concentrate in the lower stem and roots. The stem cells nearest the auxin elongate, allowing the plant to grow upward (away from gravity), but the root cells bend downward in response to auxin. To experiment with gravitropism, you need a small bean plant, two moist sponges, string, a pan and a thumbtack. Remove the bean plant from its pot, and carefully remove as much soil as possible. Place the plant's root ball between the two moist sponges. Tie the string around the width and length of the sponges to hold it together, and leave enough string to hang it from the ceiling. Place the pan under the sponges to catch drips, and add water to the sponges as needed. Observe the plant each day for two or more weeks. Record your observations. Try changing the position so the plant is upside down again.
  
  

Plant Maze

• You can make a bean plant grow through a maze.Jupiterimages/Brand X Pictures/Getty Images
  
  Most plants grow toward light (phototropism). The plant hormone auxin goes to the dark side of the plant, causing the cells there to elongate. This bends the plant toward the light to expose more cells for photosynthesis. For a cool experiment demonstrating phototropism, you need a shoe box with lid, two pieces of corrugated cardboard each half the width of the shoe box by the height of the shoe box, scissors, masking tape and a small bean plant in a 6-oz. plastic cup. Cut a hole approximately 3 inches high by 4 inches wide in one end of the shoe box. On the inside of the box, tape a cardboard piece to the left side at one-third of the length of the box. The cardboard will extend to the center of the box. Tape the other piece of cardboard to the right side at two-thirds the length of the box and extending to the center of the box. Stand the box on end with the cut hole facing up. Water the plant, put it on the bottom of the box and close the lid. Tape all openings except the cut hole, and place it in a sunny window. Check the plant in five days by opening the box. The plant will grow through the maze in the box and toward the light at the cut opening.
  
  

Does Speaking to Plants Help Them Grow?

• You might feel silly talking to plants, but try this fun experiment using four numbered pots of newly sprouted radish plants. Place the pots in a sunny window. Totally ignore Plant 1, except for watering. Lean over toward the plant and say a few nice words to Plant 2, such as a hello, for about 15 seconds a day. Spend about one minute a day leaning over Plant 3, softly saying affectionate words and gently touching its leaves. Shower Plant 4 with affection for two minutes. Lean over and stroke its leaves lovingly. Tell the plant how beautiful it is and how much you love it. You can repeat this again during each day. Record your observations for about 45 days. What do you think accounts for any differences in the plants? Consider taking periodic pictures of the plants for your records.