In What Direction Do Seeds Grow?
Students will predict and examine the direction seeds will grow and thereby learn about the effects gravity has on seeds and plants.
- two wide-mouth jars, or clear containers
- a piece of blotting paper long enough to line the inside of the jars
- paper towels
- Soak the beans overnight in water.
- Place the blotting paper snugly around the inside of each jar.
- Stuff crumpled paper towel in the middle of the jars, then fill them with water and wait until the paper towel absorbs as much of the water as it can.
- Pour off the excess water.
- Push a few of the beans in different positions (horizontal, diagonal, verticle) between the blotting paper and the glass in each jar. Keep them spaced apart and near the top of the jars.
- Have students draw diagrams of the jars and the seeds and draw their predictions of how they think they will grow.
- Keep the jars out of direct sunlight and watch the seeds grow. Water the paper towels quite regularly so the seeds will keep moist.
- Once the seedlings have reached about an inch over the jars (about a week), lay one of the jars on its side.
- Have students draw diagrams of the jars and the seeds and draw their predictions of how they think they will grow now.
- In a few days have students draw what happens. The stems of the seedlings should have bent so they could continue to grow upwards. Who predicted correctly? Why did this happen? What may be some reasons?
(Plants have growth hormones that respond to the Earth's gravitational pull. This causes roots to always grow down and stems to always grow up. This is called geotropism.)