Experimenting With Shadows and Light
Students learn why shadows are always on the move!
- Grades: PreK–K, 1–2
This lesson demonstrates how the sun casts different shadows throughout the day. Students also learn the difference between transparent, translucent, and opaque materials.
- Cardboard cut-outs of any size and shape; e.g., gingerbread men, teddy bears, etc.
- Adhesive tape
- Thread spools, one per student
- Large sheets of white paper
- Crayons or markers
- Construction paper
- Clear plastic wrap
- Wax paper
Set Up and Prepare
1. Make one cardboard cut-out for each student.
2. Plan to hold the lesson on a sunny day.
Step 1: Share with students the difference between transparent, translucent, and opaque materials. Tell them that some materials allow light to pass through them, and some materials do not. Transparent materials, such as clear glass, allow nearly all light to pass through. If you look through a piece of clear glass, you see a clear image. Translucent materials, such as wax paper, filter the light that passes through them. If you look through a piece of wax paper, images appear fuzzy. Opaque materials block all of the light. You cannot see anything through opaque materials.
Step 2: Explain that in order to create a shadow, you need a source of light, an opaque object (something that blocks light), and somewhere for the shadow to fall.
Step 3: Now distribute the cut-outs, pencils, and thread spools to the class. Have students use tape to attach the eraser end of the pencil to the cut-out figure. Then have them insert the pointed end of the pencil into the thread spool, supporting the cut-out figure.
Step 4: Ask children what they think will happen when the figure is placed in the sun. Will they see a shadow? Record their guesses.
Step 5: Take your class outside on a sunny morning. Have them each place a large sheet of paper on the ground and their supported figure on top of it. Using crayon or markers, have children trace the cut-outs' shadows onto the paper.
Step 6: Repeat the activity at noon and 2 p.m. Ask children to describe how the figure's shadow changed during the day. Explain that shadows appear long in the morning, shrink toward midday, and then grow longer until dusk.
Step 7: Now ask students what they can do to "get rid" of the shadow made by the figure. They can try using assorted materials to block the shadow: construction paper (for an opaque material), clear plastic wrap (for a transparent material), and wax paper (for a translucent material).
Step 8: Ask the children to describe what happens when they try to block the light with each of the materials. Which blocks all of the light? Some of the light? Which doesn’t block any light?
1. Help the children look through catalogs and find pictures of various window coverings. Look for some that are light-blocking such as dark shades, some that are light-filtering such as vertical blinds. How much light does each material allow to pass through?
2. Have your class write stories about their shadows. Here are a couple of ideas:
- How did their shadow become attached to them?
- What happened the time their shadow "got away?" Or when they "lost" their shadows?