To learn the basic parts of seeds and what they need to grow into a plant.
Most plants grow from seeds, which come in a variety of shapes, sizes, and textures. Within this compact package, seeds contain everything a plant needs to grow and reproduce. Some seeds, such as grass, begin life with one leaf. These kinds of seeds are monocots. Other seeds, such as beans, begin life with two leaves. These kinds of seeds are dicots.
The outside covering of seeds is called the seed coat. It protects the baby plant, or embryo, inside the seed. The seed also contains endosperm, or a food supply, that the embryo uses to grow until the plant can manufacture its own food. In order for seeds to grow into plants, they need soil containing nutrients, water, sunlight, the right temperature, room to grow, and time. In this lesson, students will have the opportunity to observe this process for themselves.
In the Motivation part of the lesson, students discuss what living things need to live and thrive. They will begin with a discussion of what people need. They will compile a list that includes the following: food, water, a place to live, ways to stay warm when it is cold and cool when it is hot, and someone to care for them. They will then go through the same exercise for animals and plants. They will discover that all living organisms have similar needs. At this point, students will probably realize that seeds, which contain a baby plant, also have these same basic needs. Throughout the lesson, they will form a better understanding of this as they look inside a seed and then plant seeds and watch them grow.
During the Development part of the lesson, students will work in pairs to dissect lima bean seeds that have been soaked overnight. Using a hand lens, they observe the embryo and food supply. Then they complete the What Are the Parts of a Seed? student sheet, which asks them to label a diagram of a seed and write down what each part does. This section of the lesson will conclude with a review of what plants need to grow.
Finally, students will have an opportunity to actually plant seeds and watch them grow.
Note: If you are buying packaged seeds, please check to see if they have been treated with fungicides or other pesticides. Do NOT buy seeds that have been exposed to these chemicals.
Begin the lesson by asking students what they need to live and grow. Make a list of their ideas on a sheet of newsprint. Suggestions should include:
- A place to live
- Ways to stay warm when the weather is cold and cool when the weather is hot
- People to help and protect them
Then ask students to think about what animals, including pets such as dogs, cats, and fish, need to live and grow. Write these suggestions on the same sheet of newsprint. Students will notice that the needs of animals are similar to the needs of human beings.
Go through the same exercise with plants. Here, too, students will notice that plants need similar things: food, water, and a place to live, such as a pot with the right kind of soil containing the proper nutrients, or space in a garden. Plants have another important need: They must be near light. In fact, light is so important to plants that they will grow toward it!
In addition, point out that soil helps regulate the plant's temperature. In the garden, mulch is another way to keep in water and regulate the plant's temperature. Plants also need someone to take care of them by watering and feeding them, and, if necessary, moving them to a better location so that they can continue to grow.
After this initial discussion, ask students what they think seeds need to live and grow. At this point, students will probably recognize that seeds need the same things to live and grow as plants and animals. If students wonder why, explain that inside each seed, there is a baby plant that will grow into a mature plant. The seed contains everything the baby plant needs until it is ready to live on its own. Explain that in the next part of the lesson, students will look inside a seed and see for themselves how seeds provide food and protection for the baby plant.
Divide students into pairs and hand out one bean seed that has been soaked overnight, a couple of toothpicks, and a hand lens to each pair. Tell students to gently lift off the outside layer of the seed. (Note: If possible, it might be a good idea to have volunteers in the classroom to help students with this activity.) Ask students to look at the inside of the seeds with the hand lens.
As a class, discuss what students are observing. Go over the parts of the seed, providing students with the correct vocabulary. Make sure they understand the following:
- The outside layer of the seed is called the seed coat. It protects the delicate structures inside the seed.
- Inside the seed, students should see two structures: the baby plant, or embryo, and the food supply. The embryo will grow into the mature plant. The food supply will nourish the growing plant until it can make food on its own.
Pass out the What Are the Parts of a Seed? student sheet. Give students time to fill out the sheet in class. Then tell them to keep the sheets available to refer to during the next part of the lesson.
Before beginning the next part of the lesson, when students will plant seeds, review what plants need to live and grow. Emphasize, too, that plants don't grow overnight. They take time, so students must be patient.
Now ask students to use their Planting Seeds and Watching Them Grow student esheet to go to Plant Investigation. Working in pairs, they should follow the directions on the website to plant seeds and watch them grow. Throughout the process, they should use the Observation Journal to observe what the plant looks like at each stage of its development.
For your information, here are the directions for the plant investigation:
- Before students begin planting, give each pair a sheet of newspaper. Tell students to cover their desks with the newspaper.
- Make available to each pair of students a cup, a plastic lid, and soil. Tell students to poke a hole in the bottom of the cup with a pencil.
- Add soil to the cup.
- Students should place one or two seeds in the hole and cover them with soil.
- Tell students to water the soil when it looks dry. They can tell when the growing plants need water by sticking their fingers one inch into the soil. If it feels dry, then watering is necessary. Tell students that when they water the plant, they should add enough water so that it starts to come out of the hole at the bottom of the cup.
- Students should write down their observations on the observation sheet. They also have the option of sharing their observations with other students throughout the United States who are working on this activity. The information about how to do this is provided on the esheet.
After the plants have started to sprout, go over the different parts that are emerging. Make sure that students can name these parts and describe their functions:
- Root: Anchors the plant and takes in water and nutrients from the soil.
- Stem: Helps support the plant.
- Leaves: Take in light, which the plant will use to make its own food.
On their observation sheets, students should draw pictures of the growing plant, labeling each part as it emerges.
As students complete each sheet, go over them to evaluate whether students can identify the parts of a seed, understand what plants need to grow, can follow the directions listed on the esheet, and can write appropriate observations. You could also encourage a class discussion to find out what they have learned. Ask questions such as:
- What are the three main parts of a seed?
- (They are the seed coat, the embryo, and the food supply.)
- What do seeds need to grow into plants?
- (They need light, water, the right temperature, nutrients, room to grow, and time.)
- What are the three main parts of a plant? What function does each serve?
- (The three main parts are the root, stem, and leaves. The root anchors the plant and takes in water and nutrients from the soil. The stem helps support the plant. Leaves take in light, which the plant will use to make its own food.)
- Do you have plants at home? If so, what do you observe about how they grow? Do they have any additional parts?
- (Answers will vary, but some plants may have flowers. Explain that flowers help the plant reproduce by attracting insects such as bees, which transfer pollen to the flower's reproductive organs.)
If students haven't done so, suggest that they use their student esheet to look at the photos of seeds on All about Seeds. Then have students bring in magazines from home. Suggest that they find pictures of other seeds, either in the magazines or on the Internet. As a class, you could develop a bulletin board showing different kinds of seeds. Alternatively, each student can make his/her own booklet about seeds.
Have students watch Desperate Houseplants on the Sesame Street website. As a class, write a short script of your own about plants and how they grow. Consider acting out your play for other classes in the school.
The following websites have other resources about plants.