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.)

Teacher Note: If you purchase the batteries in advance, please read this document for how to safely store them.

We suggest students work in pairs. Homeschool students can work on their own.

Prepare Aluminum Foil

For each student, tear off a strip of aluminum foil that’s about 4 inches wide and as long as the roll (usually about 12 inches).

In Part 1 of this activity, we recommend students work in pairs. In Part 2 of this activity, we recommend students work in groups of four. Homeschool students can work on their own, but will need someone to help with a few of the steps.

You need to set up at least two Experimental Stations with a heat source (a desk lamp with an incandescent bulb or a heated gel pack. You can heat the gel packs in the microwave, but they’ll only stay warm for about 30 minutes). For a class of 32 students, we recommend having two or more Experimental Stations. Four students will use each station at a time. When students are not using the Experimental Stations, they will be discussing ideas at their desks.

Plan Your Time

Part 1 (building a Heat Spinner) takes 15 to 20 minutes. Part 2 (experimenting with the Heat Spinners) takes another 15 to 20 minutes.

You may want to divide this lesson into two sessions, stopping after Part 1 and continuing with the Experimental Stations another day. If you plan to do the activity in two sessions, Part 2 begins here.

Prepare Push Pins (Optional)

Push each push pin into the eraser of a pencil. This makes the push pins easier for students to handle.

Prepare the Worksheets

Cut each “Get to Know Your Spinners” printout on the dotted line. Each student needs a half sheet. Cut each “Heat Spinners” printout on the dotted line. Each pair of students needs a half sheet. Cut the “Do Not Touch the Light Bulb!” printout on the dotted line to make two signs. You need one sign for each Experimental Station with a lamp.

Set Up Your Experiment Stations

To set up each station, place your heat source on a table away from drafts. If you are using a lamp as a heat source, put the “Do Not Touch the Light Bulb!” sign beside the lamp, plug the lamp in, and let it warm up for a few minutes before students experiment. If you’re using heat gel packs, heat them in the microwave right before class.

Watch Our Video for An Important Tip

Watch this video and notice when the spinner moves and when it stops. The spinner moves because rising hot air pushes on it. That rising air has to come from somewhere. In the video, the spinner moves when there’s a gap between the heat source and the cup. Cool air moves through this gap and replaces the rising hot air. This is called the “chimney effect,” and it can make a big difference in how much the spinner moves. We like to use a lamp because students usually don’t set the cup directly on top of the heat source. If you use a gel pack or some other heat source, be aware that closing off the bottom of the cup completely can stop the circulation of air and therefore the movement of your spinner.

You will need a sunny day and access to water for this activity.

We recommend students work in groups of four. Homeschool students can work on their own.

Watch This Video

This video shows how to set up a cup of water so that sunlight passing through the water separates into rainbow colors.

Find A Sunny Spot

Make sure that your chosen location will be sunny at the time of day that you plan to do the activity.

If you are working with a class, make sure each group will have space for their own glass. If you can’t find a place that will accommodate students working in groups, you can opt to do the activity as a demonstration and encourage students to try it at home.

Do A Trial Run

Before you try this with a class, do a trial run in your chosen location or in another sunny spot.

• Set up a cup as shown in the video and look for the cup’s shadow. (If you see the shadow, you know the cup is in sunlight.)
• Fill the cup with water and watch for wavy lines of light that have passed through the water.
• Put a piece of white paper on the floor where you see those lines and wait for the water to settle.
• If you don’t see colors, try tilting the cup away from the light, just a little.
• Pay attention to shadows as well as light. You’ll get the best colors if the light passing through the cup falls in a shadow, not in the light.