• To check for understanding, have students stand in a large circle in the classroom. Have one student toss a beach ball to another student across the room. Students who catch the beach ball will tell one thing they have learned, use any of the vocabulary words in a sentence, ask a question about what they’ve learned, or link their new knowledge to a real-world situation. One way of adapting this assessment is to have students in smaller circles. You will need to have a beach ball for each group.

Write the following questions on the board and have students respond in their science journals:

• Does light travel in a straight line?
• Can light bend around corners?
• How fast does light travel?

Then show students a picture of the electromagnetic spectrum (S-5-2_Electromagnetic Spectrum.doc) and have them watch the Nature of Light video clip at http://videos.howstuffworks.com/hsw/9943-exploring-light-and-color-the-nature-of-light-video.htm.

Allow students to view the video twice. Explain that the purpose of viewing the video is for students to check their responses to the warm-up questions. During the first viewing, tell students not to be concerned about taking notes or correcting their answers. As students view the video the second time, they should note at least two facts about light and check their responses to the warm-up questions. Then say, “Now that we know light travels in straight lines, it does not bend around corners, and light refracts, we will conduct three experiments that demonstrate this.”

Experiment #1: Light Travels in Straight Lines

Separate students into cooperative learning groups of two or three. Provide groups with the necessary materials to conduct the experiment, including copies of Experiment #1: Light Travels in Straight Lines (S-5-2-1_Light Activity Worksheet.doc).

Tell students the purpose of the experiment is to show that light travels in straight lines, but we can change its direction (adapted from Experiments with Light and Sound by Trevor Cook).

When students have completed the experiment, say, “The second part of this experiment demonstrates how we can change the direction of light using a mirror.”

Experiment #2: How Does Light Travel?

You will perform this experiment as students observe. Hand out copies of Experiment #2: How Does Light Travel? (S-5-2-1_Light Activity Worksheet.doc). Follow the instructions for the experiment (adapted from Fairfax County Public Schools, “The Energy of Light and Sound”) as students observe your actions. Have students record their observations.

“Now that we have discovered that light travels in straight lines, let’s look back at our warm-up questions. We also found out that light bends or refracts. The next experiment will demonstrate that.”

Experiment #3: Light Refraction

Hand out copies of Experiment #3: Light Refraction (S-5-2-1_Light Activity Worksheet.doc). Provide the necessary materials for each cooperative learning group. Observe students as necessary while they conduct the experiment. Remind them to record their observations and answer the questions written on the experiment sheet.

Extension:

• Students should access the following Web site and watch the video The Electromagnetic Spectrum (running time 2 min. 15) for homework: https://www.youtube.com/watch?v=kfS5Qn0wn2o After students have watched the video, they should write one question they still have about the visible spectrum. They should bring the question to school the following day.