Lesson 4: Photosynthesis


Activity 1: Steps in Photosynthesis

Materials: colored pencils or markers*, construction paper (kit), glue, scissors
Explain to your child that photosynthesis is the term we use to describe the process by which plants make their own food. Tell your child that photo means light and synthesis means to build. Photosynthesis is literally how plants use light to build sugar.

Before you choose from the option for this activity, watch the video and read the websites listed below.
Web Link
Web Link
Review the steps in the photosynthesis process listed below.
  1. Water and minerals enter the plant through the roots and travel through the stem and into the leaves.
  2. Carbon dioxide enters the leaves through tiny holes on the bottom of the leaves.
  3. Chlorophyll (the green pigment in the leaves) absorbs light and taps energy from the light.
  4. The plant uses the energy to change carbon dioxide and water into a sugar called glucose.
  5. The plant uses the sugar as its food.
  6. Photosynthesis also produces the oxygen needed by people and animals.
Give your child the sheet, "Steps in Photosynthesis," and let her cut the steps apart (without the numbers). Fold two pieces of construction paper horizontally into three parts as pictured on the diagram. At the top of each section of the paper, ask your child to glue the steps of the photosynthesis process in order. Then she will either match the pictures with the steps (Option 1) or illustrate each step (Option 2).
Steps in Photosynthesis Diagram

Option 1

For this option, your child will match the picture with the steps in the process of photosynthesis.

Option 2 (Advanced)

For this option, your child will order the steps and illustrate each step in the process of photosynthesis on construction paper. (Do not provide pictures.)

Activity 2: Experimenting with Photosynthesis

Materials: grass seed (kit), piece of cardboard, potting soil (kit), shallow pan
Ask your child how water gets to the leaves of a plant. Review the fact that water is absorbed into the roots from the soil. Then discuss how plants use the sun to make food. To demonstrate that plants need sunlight for photosynthesis, conduct the following experiment.

Spread some potting soil on a pan, sprinkle grass seeds on top, and water the soil until it is moist but not wet. Keep the soil in a sunny place and water it to keep it moist for about a week. Once the grass is about 1/2-inch high, use a piece of cardboard to cover half of the grass. After another week has gone by, compare the grass in the sunny side of the pan to the dark side of the pan.

Discuss with your child that plants need light in order to grow. Without light, they cannot carry out photosynthesis to create the energy they need to live.

Note: If the weather is cold, you can modify the experiment by using a household plant. Let your child cut two or three shapes out of aluminum foil about the size of half of a leaf on the plant. She can paperclip the shapes to the leaves. After four or five days, she can take the shapes off and compare the leaves that had the shapes with those that did not have an aluminum shape.

Activity 3: A Mini Quiz

Materials: science journal
Now your child will take a quiz about what she has learned about plants so far. Tell her to answer each question on the page, "A Mini Quiz," using complete sentences. She can find help in books and previous activities. If your child needs more space for her answers, she can write them in her science journal.
Student Activity Page