From Seed to Seed:
Plant Science for K-8 Educators

Activity 14: Sunscreen

Grades: K-4

Associated Lesson Topics:

• Photosynthesis
• Light requirements

National Standards:

• SCIENCE: Standard A, Standard C

Planting the Seed...

Why do you think leaves look the way they do? What purpose do you think leaves serve? How does the structure of a leaf help it serve this purpose? What does the leaf need to do its job? Have students brainstorm a list of things that leaves might need to do their job. Below we include the procedure for testing whether plants need light to do their job. You can follow this procedure or encourage students to come up with their own.

Teacher Information:

The primary purpose of leaves is to photosynthesize. In order for photosynthesis to take place, the leaves need to be exposed to light. In this experiment, your students will learn that without light, plants are unable to photosynthesize and produce food.

Necessary Materials:

• Plants. Since the plants will not be irreparably damaged in this activity, you can use those that are already growing in your classroom or garden for other purposes.
• Cardboard or black construction paper.
• Scissors.
• Paper clips.

Procedure:

• Have students cut the cardboard or black construction paper into pieces large enough to cover at least half of a plant leaf.
• Attach the cardboard/paper pieces to the leaves using the paper clips.
• Leave the cardboard/paper in place for four to five days. If you are conducting this experiment inside, place the plants in a location where they will get plenty of light.
• Remove the cardboard/paper pieces from the leaves and have students record their observations.

Harvesting the Crop...

What do you notice about the parts of the leaf that were covered? Which part of the leaf looks healthier-the part that was covered or the part that was exposed to light? From your results, what can you conclude about what plants need to do their job? This provides you with the opportunity to begin exploring food production in plants and the use of light in photosynthesis.

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