GO IN DEPTH

Sky 3: Modeling Shadows

Materials

Select one (or more) of the following models:

One-dimensional map/model:

  • a large sheet of paper or poster board
  • pencils, crayons, and markers

Three dimensional map/model:

  • some appropriate area in the classroom
  • cardboard
  • scissors
  • glue
  • tape
  • pencils, crayons, and markers
  • a bright lamp

Outdoor three-dimensional map/model:

  • an appropriate place on the school grounds
  • larger pieces of cardboard
  • scissors
  • glue
  • tape
  • pencils, crayons, and markers
  • any additional material students can use to create landmarks like the tree, Bear's house, and so on
 
Sky 3: Modeling Shadows

Purpose

To demonstrate understanding of shadows by creating a physical model of concepts learned.


Context

This lesson is part of a four-lesson series in which students observe the daytime and nighttime sky regularly to identify sequences of changes and to look for patterns in these changes. At the K-2 level, learning about objects in the sky should be entirely observational and qualitative. The priority is to get students noticing and describing what objects in the sky look like at different times. (Benchmarks for Science Literacy, p. 62.)

The sun, moon, stars, clouds, birds, and airplanes all have properties, locations, and movements that can be observed and described. Ideally, students should engage in direct observation of both the daytime and nighttime sky throughout this lesson series. However, the recommended Internet resources can be helpful to enhance student experiences, or if opportunities for direct observation are limited. This investigation requires that observations be ongoing, so that students can look for patterns over time. As children become more familiar with objects in the sky, they can be guided to observe changes, such as nigh and day and the seasons.

In Sky 1: Objects in the Sky, students investigated objects in the daytime and nighttime sky.

In Sky 2: Shadows, students explored making shadows and tracking the movement of an object over the course of a day to look for patterns.

In this lesson, students will construct models to demonstrate their understanding of shadows. Many questions and suggestions for variants on the activities are presented to allow you to tailor this lesson to your particular needs. It is best to make the map of Bear's neighborhood when the sun is relatively high in the sky, either near the beginning or the end of the school year. You'll want to measure the sun shadows with students at least twice, and perhaps three or four times during the year, to see how they vary with the time of year.

Sky 4: The Moon has students drawing the moon's shape for each evening on a calendar and then determining the pattern in the shapes over several weeks.


Planning Ahead

You will need Bear Shadow by Frank Asch to conduct this lesson. Review the activity used in the Development section to determine which type of model your students will construct. Gather the required materials, and prepare to do the activity in the conditions described.


Motivation

If you wish, reread Bear Shadow by Frank Asch and discuss.

You should have completed Shadows, the second Science NetLinks lesson in this series, or have measured sun shadows in some other context, so your discussion can be more pointed. You can, for example, discuss the time of day when the various events occur, and the direction in which the Bear's shadow will fall at these times.


Development

Divide students into groups of 3-4. Each group will make a 3-D model of the neighborhood where Bear lives. The map/model should show clearly which direction is north, either with an arrow on a map or by orienting a three-dimensional model correctly with respect to the actual directions. Be sure the map/model includes:

  • Bear's house
  • the pond where he went fishing
  • the brook he jumped over
  • the tree he hid behind
  • the cliff he climbed
  • the place where he tried to nail the shadow to the ground
  • the place where he dug the hole to bury the shadow

One-dimensional map/model:

The simplest way for children to construct their maps/models is to draw them on paper, but this is also the most abstract and demands a great deal of transfer from the observational world of shadows cast by real objects on real surfaces to imagining an object drawn on paper casting a shadow. This approach should be used with older children who have had some previous experience drawing maps of such places as their homes, their school, or a small neighborhood. The added difficulty of mapping an imaginary neighborhood, where the only clues to the relative positions of things are the shadows that they cast or are cast upon them, is substantial.


Three-dimensional map/model:

An easier approach is to construct the imaginary neighborhood in the classroom. You can create a three-dimensional model by making a tree, a cliff, and a house that stand up and using a doll or other model for Bear. Now, by turning out the lights and using a bright lamp to represent the sun, the model can be checked to see how faithfully it represents the neighborhood shown in the book. The degree of abstraction is smaller, but the motion of the sun is only simulated, so some children, especially younger ones, might not really see the connections between this mapping activity and measuring sun shadows.


Outdoor three-dimensional map/model:

For young children, it's almost imperative to construct the neighborhood/model out of doors where the position of the sun and the sky is determined by the rotation of the earth, its tilt, and its location in its yearly circuit of the sun, so it does not have to be simulated. Students will have to check their map/model several times during the day to be sure it represents the neighborhood shown in the book.


If a map is simply drawn on paper, each group should prepare its own map and then present it to the whole class, with arguments for the choices made. When there are differences between and among groups, discuss whether each map is a valid representation; that is, it explains the pictures shown in the book. Any map that does this is "correct." Since the locations of most of the features relative to one another aren't determined by the pictures, students will have valid reasons for choosing quite different arrangements. This is a valuable lesson. There is not always one correct solution to a problem; several different ones may explain the data that are available.

For the three-dimensional models, one approach would be to assign each group a feature to place on the model (after a site for the pond is chosen). When all of the features have been placed, each group can explain the reasoning that led them to their placement. Again, there may be disagreements and the criterion for "correctness" is whether the placement explains the pictures in the book. As preparation for the mapping/modeling activity, there are several questions that might be posed to all the students, or to the groups, either to answer "immediately" or to direct thinking during the map/model construction. Some of these might be used as part of your assessment of the children's understanding of what has been done and/or their attentiveness to the details of the book and their reasoning from it. In all cases, the response to a question should contain an explanation of how the answer was obtained, not just the answer itself.

  • At what time of the year does the story happen?
  • At what time of day did Bear go out to fish?
  • At what time of day did Bear try to nail shadow to the ground?
  • At what time of day did Bear try to bury the shadow?
  • How long did Bear nap?
  • How many windows are there in Bear's house?
  • Which direction does the door of Bear's house face?
  • How are the pictures that show the passage of time while Bear naps like your measurements of shadows (from previous lesson)?
  • How are the pictures that show the passage of time while Bear naps different from your measurements of shadows (from previous lesson)?
  • What other questions can you answer?

Assessment

Allow groups to share their models with the class. Ask students to explain what is portrayed and what is not portrayed. How is the model like the "real" thing? How could the model be improved? If they could use any materials at all, what would they do to make the model "better?"


Extensions

There are many possible extensions that can build upon and enrich what has been done. Two such extensions, depending on the interests of the children, are to learn and write more about bears (the lives of real bears or more about Bear and other imaginary bears) and to learn and write more about shadows. Based on further reading or what they have learned in the above activities, students should use what they have learned as a basis for writing.

You can also use Bear Shadow to address Benchmark 5A The Living Environment: Diversity of Life (K-2) #3: Stories sometimes give plants and animals attributes that they really do not have.

As children find out more about bears, ask them to reread the book and list ways that Bear behaves like a real bear and ways he acts like a person, a child. Examine other books in the same way to help children begin to make distinctions between "true" books and imaginative writing or fiction. Such examinations could be the basis for expository writing by the children, or they may write and illustrate their own story about bears and shadows or both. Cubs Corner (the kids' page of The American Bear Association website) is a good resource for young children who wish to learn more about bears. Another useful resource is the Idaho Public Television's Dialogue for Kids on Bears, although the information provided there does have a state-based perspective.


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Lesson Details

Grades Themes Type Project 2061 Benchmarks National Science Standards

Other Lessons in This Series

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