Students will test a variety of objects to see if sunlight passes through them. Students will then be introduced to three new vocabulary words - opaque, transparent, and translucent. Topics are suggested for a discussion of why we need to know about shadows.

Engaging Questions

• Which objects allow light to pass through easily? Why?

• Can you think of more materials that would be transparent?

• What are some important uses for transparent materials?

Teacher Goals

• Students will predict and experiment with a variety of materials to learn which ones will let light pass through.

• Students will acquire an understanding of three new vocabulary words: transparent, translucent and opaque.

• Students will increase their knowledge of the importance of shadows.

Required Resources

• Suggested Material List
  
  pane of glass
  sheet of paper
  piece of plastic (transparency film)
  cardboard
  aluminum foil
  waxed paper
  tissue paper
  glass of water
  mirror
  piece of cloth
  paper plate

• Resources

  • "Will Light Pass Through?" Rubric
  • Shadow or No Shadow?

Steps

1. Collect Materials

   Gather materials for your activity. A list of suggested materials is under required resources.

2. Make Predictions

   For each of the materials, make a prediction, choosing from one of the following:

   1. Lets light through.
   2. Lets some light through.
   3. Does not let light through.

   This can be documented on the data sheet "Shadow or No Shadow?"

3. Try it out!

   Go out in the sunlight, and try out each material! Make a note about into which category it fits. Make notes on your data sheet.

   1. Lets light through
   2. Lets some light through
   3. Does not let light through

   If there is not enough sunlight, optional suggestions are provided under teacher notes.

4. Rubric

   Complete the Rubric to document and assess how close your predictions and findings were.

5. Data Form

   Add the information you recorded from your experiment on the "Shadow or No shadow?" form.

6. Discussion and Vocabulary

   Discuss how accurate your predictions were. Discuss what differs in each material and about whether the material lets light through. Introduce the three new vocabulary words: transparent translucent opaque

   Definitions are under teacher notes.

7. Usefulness

   Talk with students about when it would be important to have an understanding of shadows and their effects.  A list of suggested topics is provided under teacher notes.

Teacher Notes

• If there is not enough sunlight in order to do the activity effectively, it can easily be done in the classroom using a flashlight, a film projector, or an overhead projector.

• In the "Trying It Out" section, some students may be intrigued by the way the light behaves on the aluminum foil and the mirror. It is true that they are transparent, and students may also notice the reflection of the light from them. 

• For an extenion activity, have students move the objects up and down, and notice the difference in the shadow. Again, this can be easily done in the light of an overhead projector or film projector also.

• Definitions:
  transparent: allows light to pass through easily, no shadow.
  translucent: allows some light to pass through, casts a light shadow.
  opaque: does not allow light to pass through, casts a dark shadow.

• Importance of Understanding Shadows:
  Helps in staying cool
  Photography
  Gardening (sun vs. shade at different times of the day)
  Solar power
  Telling time
  Construction

• Duration: This can be completed in one class period of one hour.

Learner Notes

• Shadows can be fun things with which to experiment. Look all around you to find objects that fit each of the three categories you learned about!

Mentor Notes

• Encourage your son or dagher to take note of different objects and the way they interact with light. Opaque objects will be the easiest to find, but encourage them to look for transparent and translucent objects as well.