We learn that light only travels in straight lines. Light can’t bend around corners or travel through most solid objects. When light is blocked by an object, a shadow is formed behind it. Opaque materials do not let any light pass through them. They block the light. Wood is an example of an opaque material. Transparent materials let light pass through them in straight lines, so that you can see clearly through them. Glass is an example of a transparent material. Translucent materials let some light through, but they scatter the light in all directions, so that you cannot see clearly through them. Tissue paper is an example of a translucent material.
We make puppets and use a shadow box to tell stories, exploring how shadows change when they are closer and farther away from a light source. If an object is moved closer to the light source, the shadow gets bigger. If an object is moved further away from the light source, the shadow gets smaller. When there is no light there is darkness and a shadow is an area of darkness.
Body Outline Shadows – Each child lays on a large piece of brown paper. The teacher traces their body and cuts out their outline on top of linoleum with a rotor cutter. Place brown body outline on top of a large black piece of paper. Place flat rocks on top of outline to secure in place. Using a roller with bright paint, roll on edges of body. Then remove outline and you have a shadow of your body outline painting.
Sundials – In ancient times, people relied on sundials to mark the passage of hours and minutes. Sundials measure time by the position of the sun. They can be amazingly accurate, and are surprisingly simple to make. The instructions here are for a basic sundial similar to the rudimentary stone versions once used. Called gnomons, these sundials consisted of a vertical stick or pillar that cast a shadow on sunny days. The length of the shadow was measured to determine the time. For this activity, you’ll be using a small stick and marking its shadow length with stones to indicate the hour. You’ll need a stick or pencil and 12 stones; Watch or clock Modeling clay (if making the sundial on a paved surface). Choose an unshaded area to set up your sundial. Put the stick or pencil in the ground, or in a large piece of modeling clay, if your space is on a concrete or wooden surface. Observe the stick’s shadow carefully over the course of the day. Add a stone to your sundial for each hour, from sunup to sundown. Mark the exact spot where the shadow falls each hour. To make telling time easier, label each stone with the corresponding hour in which it was placed. Because Roman numerals were traditionally used on sundials, they can be a great way to make your sundial more authentic. Using your sundial to tell time may take practice. Start by looking at the sundial on the hour, which is when the shadow should fall precisely on a stone. With practice, it will become easier to determine the time, even when the shadow falls between two rocks. It should be possible to accurately determine the time to the nearest 15 minutes with the sundial you’ve created.
Shadow Tracings – On a sunny day set a toy or interesting shape on a piece of paper in the sun. Trace the shadow with chalk or oil pastel every 20 minutes to see how a toy’s shadow (like our shadow) changes as the Earth moves around the sun. In the morning, the Sun is low in the eastern sky, so the toy’s shadow lengthens and points more toward the west. As the Earth turns, the Sun appears to rise in the sky and move west, making the toy’s shadow get shorter and move in the opposite direction. As the Sun sets in the west, the shadow points east and grows longer until it disappears in the dark. Add watercolor to finish your artwork.