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K-1: The Senses

Author(s): Barbara Tharp, MS, Michael Vu, MS, Delinda Mock, BA, Christopher Burnett, BA, and Nancy Moreno, PhD.

We Need Light to See

Procedure: Part 2 (cont.)

Have students use the mirror to observe the size of their pupils with the lights on. Then, turn off the lights for a few minutes. Explain that students should be ready to observe the size of their pupils again, as soon as the lights are turned back on. Make sure everyone’s mirror is ready, and then turn on the lights. Ask, What happened to your pupil? Students should notice that their pupils became larger while the lights were out.

Explain that the iris and pupil work together to allow light into the eye. When the room was darker, their pupils opened wider so their eyes would receive more light.

Remind students that light is essential for vision. Reinforce this idea with a flashlight and the sheet of construction paper. Turn off the room lights again. Cover the flashlight beam with the prepared sheet of black construction paper. Have students observe how much light gets through the small hole in the paper to illuminate a white surface. Enlarge the hole in the paper and again have students observe how much reaches the white surface. Ask, Do you notice a difference? Why do you think this happened? (The larger hole, like a wider pupil, allows additional light to pass through.)

Ask, How do you think information about the objects you see travels from your eyes to your brain? Have one student use a piece of yarn to connect the eye and brain on the class body cutout. Encourage students to recall how signals travel through the spinal cord, all the way to the brain. Similarly, information gathered in the eyes travels to the brain via optic nerves. (Specifically, the retina sends nerve impulses along the optic nerve to areas in the brain.)

Ask, Do you think it takes a long time for information to travel from your eyes to the brain? Why or why not? Help students understand that information travels rapidly in the nervous system.

Have students write one or more sentences in their science notebooks about vision.

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