A science experiment on beans is an inexpensive, straightforward way to explain the different parts of a seed and its functions to your third-grade class. Your science lesson should include an examination of the anatomy of a bean, as well as a growing experiment to solidify the information. This one- to two-week lesson can provide valuable information on the structure and characteristics of living things and the life cycle of plants.
Hand students a worksheet with a diagram of a bean. The sheet should include definitions of important terms for the bean. Include micropyle, hilum, seed coat, embryo and cotyledon. Micropyle is a tiny pore, located on the bean's concave side, that allows the seed to absorb water. Hilum is also on the concave side. You can find a small scar where the bean used to be attached to the plant it grew from -- akin to the bean’s belly button. Seed coat is the outer papery layer that protects the seed. The embryo is a tiny developing plant inside the bean that will grow from the plant if conditions are right. This will look like a small group of fibers inside the bean. Cotyledon is the white section inside the plant with food stores for the plant during initial growth. When you slice a bean open, this makes up the majority of the inside of plant and surrounds the embryo.
Allowing kids to examine a bean will tie in the information from the worksheet with the real object. Soak some pinto or lima beans overnight in water. Hand each student a bean and ask them to slowly rub the outer covering off. Help them split the seed in half down the natural line that runs the perimeter of the bean and ask them to examine the internal parts. The kids should reference the worksheets for the correct name of each item. Using a magnifying glass to look at internal parts can make it easier and fun.
A growing experiment will demonstrate the life cycle of a bean -- how the bean grows from a tiny bean into a plant that will eventually produce its own beans. Hand each child one resealable plastic bag or glass jar, one water-soaked bean and one wet paper towel sheet. The kids should fold the towel around the bean and place it in the jar or bag. The next day, have kids carefully remove the paper towel, unfold it and look for the bean shoot without touching the bean. Ask them to fold the paper towel again and place it back in the jar or bag. Each day pull the bean out and examine growth. Over time, your class will observe as the bean sprouts a root, loses the seed coat, the root grows hairy secondary roots and finally the plant grows leaves. Compare findings each day. Have kids write down observations each day. Keep the paper towel damp at all times and replace torn towels.
At the end of this unit, test the students’ understanding of this bean lesson. The exam should include a diagram that they must label, as well as some fill-in-the-blanks and multiple choice questions. Include all pertinent terms somewhere on the test.
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