Easy Plant Experiments for Seventh-Graders

Sunlight's Importance

• Take two plants in flowerpots of soil and set them by a window. Put one plant in a box that will not let in sunlight except from a large opening on the side of the box not facing the window. After two weeks, remove the boxed plant and compare to the un-boxed plant. This experiment will show sunlight's effect on plant growth and development.

Earthworms and Plant Growth

• Take two plants and set them by a window in a flowerpot. Ensure that both plants are in the same amount of soil, but put at least a dozen earthworms in one of the pots. After two weeks, compare the plant growing in earthworms to the plant growing only in soil. This experiment will show the beneficial effects earthworms have on plant growth -- namely, their contribution to loosening hard soil and consuming harmful bacteria.

Water's Benefits

• Place four plants in flowerpots of soil near a window. Water the plants daily. Water one plant with 1 ounce of water, one with 2 ounces, one with 3 ounces and one with 4 ounces. Water the same plant with the same amount of water every day. After two weeks, measure and record the results. This experiment will show the effects that exposure from certain amounts of water have on plant growth.

Water and Milk

• Place two identical plants in pots of soil by a window. Water one plant with water and the other with milk on a daily basis, using the same amount of milk and water. Keep watering the same plant with water and milk, respectively. After two weeks, measure and record the results. This experiment will show the effects of milk on plant growth and development. Using milk as a water replacement may harm the plant, as only diluted milk would aid the plant's health.