Italicized font represents information to be shared orally or physically completed with the students at this time.

The non-italicized font represents additional information included to support the teacher’s understanding of the content being introduced within the CELL.

ASK WHY

Remind students that light is all around us. It has the ability to tan or burn our skin. It can be harnessed to melt metals, create electricity, and heat our food. It gives us sight, color, warmth, and enables gadgets like computers, cameras, televisions, traffic lights, mirrors, eyeglasses, and microscopes to function.

BRANCH OUT

Remind students that physicists have created blue LEDs (light-emitting diodes) that have made today’s flat-panel, full-color computer monitors and TV screens possible. The technology also is being incorporated into water purifiers, which use ultraviolet light to kill bacteria and viruses in water.

GET FOCUSED

GO DEEPER

As a class, read the Background(s) in the Investigation. Have students read the information aloud or silently to themselves. When students have finished, discuss the following concepts as a class:

• The Law of Reflection states that the angle at which light hits an object is equal to the angle at which light is reflected from the object.
• The angle at which light hits an object is called the angle of incidence.
• The angle at which light is reflected off of an object is called the angle of reflection.
• The Law of Reflection states that the angle of incidence is equal to the angle of reflection.

Note: These concepts are integrated into the Background(s) and are used to deepen students’ comprehension of the big ideas.

LEARN THE LabLearner LINGO

The following list includes Key Terms that are introduced in the Investigation Background(s). They should be used, as appropriate, by teachers and students during everyday classroom discourse.

• reflection
• Law of Reflection
• angle of incidence
• angle of reflection

Note: Definitions of these terms can be found on the Introduction page to the CELL.

Note: Additional words may be bolded within the Background(s). These words are not Key Terms and are strictly emphasized for exposure at this time.

SET FOR SUCCESS

• Tell students that when studying reflection, it is useful to describe the events of reflection in terms of how light first interacts with a substance and how light is reflected off of a substance. Scientists give the light in each of these two steps different names, incident light, and reflective light.
  • Incident light is light from a source that interacts with the substance.
  • Reflected light is the light that is bounced off of the surface.
• Explain that scientists characterize the way in which the incident and reflected light interact with a substance by describing the angles at which each comes in contact with the substance. These descriptions include the angle of incidence and the angle of reflection.
• Play the video below. Stop to ask students questions or answer students’ questions when necessary. Remind students to follow along with their SDRs and make any notes that they think might be helpful.
• After the video, direct students to divide into their lab groups to discuss their strategy for the lab. For example, they may assign certain group members to perform specific functions during the lab.

Note: The purpose of the video is to allow students to anticipate the laboratory experience they will soon encounter. Students should leave this PreLab session with a firm idea of what to expect and how to perform in the lab.

Note: Homework is posted below the video.

HOMEWORK

Tell students that they should review the Investigation in preparation for the Lab.