Backyard Biology

Nature stories from my backyard and beyond

Nature Activities

Seed Power

Friday, October 9, 2009

In this experiment, you will use craft supplies and a few dried beens to demonstrate the new plants, though delicate, are capable of feats of enormous power.

A seed is the beginning of a plant. It is the end product of a reproductive process that begins with flower production and ends in pollination, or the transfer of male pollen to the female ovule (or egg). The result is a seed: a plant embryo packaged in a protective wrapper and enclosed with some stored food.

Seeds come in all shapes and sizes. Large as a cocoanut or small as a grain of sand, they all contain stored energy that allows them to grow and develop. Just where does this energy come from? The power of a seed is locked in the oils, fats and carbohydrates (starches) that fuel its growth. With this energy, the baby plant is able to germinate. Its cells awaken and expand, exerting a force on the outside world.

In this way, tree roots lift and break through concrete sidewalks, weeds grow through paved roadways and the roots of houseplants crack the pots they are planted in. In this experiment, bean seeds use a combination of stored energy and water pressure to burst through (or in some cases lift off) the plaster of paris they are planted in.

Procedure:

-Begin by posing a (seemingly) obvious question: Who’s stronger - you or the seed? Back up your answer by making a list of your feats of strength. What about plants? Can they be strong? If so, how? Weather permitting, go outside into the community, school parking lot or playground, and look for signs of plant “muscle power.”

-What do you think would happen if seeds were planted in plaster of paris? Record your predictions.

-Soak a few bean seeds in water for 24 hours.

-Mix plaster of paris with water to a putty-like consistency (3 parts plaster of paris to 1 part water) and pour about one inch into a coffee can or cup.

-Plant the seeds about 1/4 of an inch down by poking them into the plaster and smoothing over the top. Plant other seeds in soil and pour the plaster of paris on top.

NOTE: For faster results, soak the seeds for 48-72 hours. It is also a good idea to plant more than one seed in each cup, as even in the best of conditions, not all seeds grow.

-The plaster will grow in about a half hour. Seeds will probably not need watering. However, if the plaster is extremely dry after a few days, add water sparingly. Within a week or two, the seeds should break through the plaster.beans under plaster image

-Note the results. Have you changed your mind about plant power?

Extending the Science:

-Try the same experiment with other seeds. Are some stronger than others? Set up n experiment to find out.

-Take a walk looking for things growing through cracks.

-At the beginning of a school day, fill a container (coffee can, jelly jar, anything with a snap-on plastic lid) with whole dried peas or bean seeds, just to the very top. Fill the container with water (again, to the very top). Snap on the lid, cork or stopper. Wait six or eight hours, watch the swollen, growing seeds pop the top off.

Future Possibilities:

-Discuss how people utilize plant power. We eat seeds, leaves, stems and roots for all types of foods - which in turn provide us with the energy to play hopscotch, do jumping jacks, (or our science homework...as the case may be.)

My thanks to Lisa Warren from the Museum of Science in Boston for this experiment. If you have an activity you would like to share, please contact me