Unit F: Forms of Energy

What inventions help people see in the dark?

1. Get Set to Explore


  • heat: The energy of motion of the particles that form matter; also called thermal energy.
  • infrared light: Electromagnetic radiation that has a wavelength just a little longer than that of visible light.
  • light: Electromagnetic radiation that people can see; also called visible light.

Building Background

  • If you can, darken your classroom or take the class to a room in the school that has no windows. Turn out the lights and ask students what they can see. If the room is very dark, students will not be able to see much. Then, give volunteers small flashlights and ask them to shine them on the ceiling. Let the class discuss what the small amount of light allows them to see. Review the definition of light, given above.
  • Go over the definitions of the other vocabulary words with the class. Make sure that students understand the difference between visible light and infrared light. Refer to the diagram of the electromagnetic spectrum on Student Edition page F65 and to the detailed information on infrared radiation on Student Edition page F90.
  • Direct students to think back to their experience in the dark room and to imagine that they could see infrared light, as well as visible light. Encourage them describe what they think they would have seen.
  • Explain that new technology has been developed that allows people to see in dark places. Pose the Discover! question. Let students brainstorm to come up with answers, from the obvious to the speculative. List their ideas on the board.

2. Guide the Exploration

  • Invite students to launch the Discover! Simulation. Students should choose one of the sets of goggles by clicking them and then explore the scene using the panning tool.
  • Students should spend some time viewing the scene through one set of goggles. They should take notes or make a sketch of the things that they can see with the goggles but they couldn't see without the goggles. Then they should switch to the other goggles and repeat their careful observations. Point out to students that they can learn how each set of goggles works by clicking the buttons near each set.
  • After students have finished Step 2, lead a class discussion for students to describe what they were able to see with each set of goggles. Let students return to the simulation to look for any objects that they missed on their first viewing.

3. Review/Assess

  • Review Step 3's Wrap-Up text with the class, and encourage students to ask any questions they have. Help clarify any confusing concepts.
  • You may wish to refer back to the question you asked about what students would have seen in the dark room if they had been able to perceive infrared light. Guide students to realize that if they had had a pair of these goggles, they would have seen their classmates, teachers, heat ducts or registers, and anything else in the room that was giving off heat.
  • Direct students to return to the simulation, and present the Extension question to the class. Students should think back to what they know about plants and animals and compare how each functions. Guide them to understand that animals have a higher metabolic rate than plants do, and so animals give off more infrared light.

If time permits, present students with the following question and activity:

  • Critical Thinking Evaluate Which set of goggles do you think would generally be most useful and why? Answer: Some students might think that the thermal-imaging goggles would be more useful because they allow people to see all living things fairly easily. Other students might think that ambient light goggles would be more useful; they simply enhance the type of light we normally perceive.
  • Inquiry Skill Work Together Look at the list of different inventions your class came up with to help people see in the dark. Pick one that has not yet been invented. Work with a partner to make a drawing of the invention. Use labels to explain how the invention would work. Answer: Possible ideas might involve sonar, or new types of batteries; accept any idea based on scientific principles.

4. Reaching All Learners

English Language Learners

Let English Language Learners pair up with native English speakers to work on the vocabulary related to this simulation. They should make flashcards for the vocabulary words listed in the Teacher's Resource Book and any other words you think will be useful. The front of each flashcard should have the science word; the back should have a definition and a picture or diagram that illustrates the definition.