We suggest students work in pairs. Homeschool students can work on their own, but may need a partner to help with a few steps.

Prepare String

Each student will need one piece of string that is 18 inches long.

Extend this Activity and Create Robot Hands

In the Extensions, we have a fun engineering extension activity where students combine four robot fingers to create a robot hand. We recommend having each group of four students assemble a hand using the robot fingers they each made.

Check our "Extensions" for further instructions.

Try Making An Image With the Lens Before Class

As soon as you have a 3X magnifying lens, use it to make an image. For the best image, you need a dimly lit room and an interesting light source — like a window that lets light in, a lamp with a shade, or a television. Watch this short video for a demonstration.

After you’ve made an image, check to see what will work in your classroom. Do you have a door to the outside that you can prop open? A bright window? An interesting light fixture?

If you have a large class, you can set up a few stations with lamps around the room, or send students in batches to a window.

Hold On To The Eye Models

If you will be teaching the next lesson "How can some animals see in the dark?" , then you must save the eye models that students make in this lesson. Keep them in a safe place until you are ready to teach the next lesson.

We suggest students work in pairs. Students need the complete eye model (magnifying lens and the index card “retina”) that they made in the previous lesson. If any students were absent for this activity, you can pair them with someone who has an eye model. Homeschool students can work on their own, but will need a partner for some parts of the activity.

Watch This Quick Video

In the first activity, students will experiment to see how their eyes change in response to changes in the light around them. Watch this video to see the change they are looking for. (You can also watch for this change in your own eyes. Look at your eyes in a mirror in a dark room and watch what happens when you turn on the lights.)

We suggest students work in pairs. Homeschool students will need a partner for the activities.

Each pair of students will need a table or desk.