Academic journal article Science and Children

Shadow Play: Linking Shadows to Learning about Seasons

Academic journal article Science and Children

Shadow Play: Linking Shadows to Learning about Seasons

Article excerpt

A bunny rabbit playfully hops across the wall. Then hands realign and fingers shift to make a hawk soar toward the ceiling. Most children have enjoyed the delightful experience of playing with shadow puppets. We build on this natural curiosity to help students link shadows to complex astronomical concepts such as seasons. The following inquiry-based lessons come from our work with fourth- and fifth-grade children as they investigate properties of shadows.

Shadow Misconceptions

Students frequently have an incomplete understanding about shadows. Some of the common misconceptions include that shadows exist independent of light sources and may come out of or be projected from a person, animal, or object. Some students think that shadows are always present but need light to illuminate them to be seen. Other students believe that reflected lights or clouds are involved in creating shadows. Some students even give shadows human attributes, believing that shadows can willfully follow a person around or be cowardly and hide when afraid (Eschach 2003).

Daily Shadow Changes

On a sunny day, students can venture outside and directly observe their own shadows. This activity works best if students are directed to select a location that will not be cast in shadow by buildings or large plants at any time during the day. Students must stay in the designated area at all times and be instructed to never look directly at the Sun. caihion

Working in pairs, students select an observation spot, draw a circle around their feet with chalk, and write their names inside the circle so they can find the same location later in the day. The cardinal directions (N, S, E, and W) are marked on the perimeter of the circle. Students take turns tracing their shadows with chalk at 10:00 a.m., noon, and 2:00 p.m., and they put an x along with the time to indicate the direction of the Sun. In their journals, students draw a diagram of their observations, noting which direction their shadow "pointed" at each time of the day along with the direction of the light source, the Sun. After data are gathered, we ask students productive questions to help them see patterns in their data (Elstgeest 2001). Productive questions are those that children can answer through their own observations and related data. Examples include:

* What do you notice about the shadows throughout the day? What happens to the length of the shadow throughout the day? (It changes length, getting shorter from morning to noon and then longer from noon to afternoon.)

* What happens to the direction of the shadow? (It changes.)

* Where is the shadow located relative/compared to the Sun? (Always opposite the Sun.)

* At what time was the Sun out/visible and there was no shadow at all? (Never in our data.)

Find additional information on productive questions and specific examples of each question type online (see NSTA Connection).

The next day, a slightly more abstract version of the same activity is conducted. Pairs of students are given 1 oz of modeling day, a pencil, a large piece of white paper, and a flashlight. They poke the pencil into the modeling clay vertically and place it on the center of the paper. While imagining the table being the Earth's surface or the horizon, they shine the flashlight in an arc over the pencil. They trace the resulting shadows cast at 6:00 a.m. (at the table level), 9:00 a.m., noon (above the pencil), 3:00 p.m., and 6:00 p.m. (at the table level) on the large white paper. Again, we conclude with questions:

* What do you notice about the shadows at different positions or angles of the flashlight? When were the shadows the longest? (When the flashlight is at the table level.)

* The shortest? (When the light is above the pencil.)

* Where was the shadow located relative to the flashlight? (Always opposite.)

Students are encouraged to note their analyses in writing. …

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