A 60 minute lesson in which students will compare shadows from point and extended light sources.
Prior to conducting the lesson, review the procedure and equipment required for the activity.
Clear drinking cups/glasses
Pieces of opaque cardboard
This lesson contains a link to an external video. Please watch the video prior to presenting this lesson to ensure that the content is appropriate for your students.
Watch the Nature of Light Source and Shadows video on YouTube. Revise the following statement: The narrowest source of light gives the sharpest shadows. Encourage the students to think about and share whether their experiences of shadows match this hypothesis.
Display and discuss slides 15-20 of the Light Fantastic PowerPoint. Reiterate the differences in the light ray diagrams on slide 18. Ensure that the students understand the meaning of the terms ‘point light source’, ‘extended light source’, ‘umbra’ and ‘penumbra’. Add these new words to the classroom word wall display.
Provide the students with a copy of the In the Shadows Worksheet. Read through the activity step-by-step and answer any questions the students may have about the task. Assist the students in collecting and preparing the equipment required for the activity.
Monitor the class as they conduct the activity in small groups. Support the students to complete the diagrams of the different shadows. Ensure that they include the labels and other elements required by the task.
Review the statement: The narrowest source of light gives the sharpest shadows. Discuss how the activity supports or refutes the hypothesis, using the observations and learned information about extended and point light sources.
Encourage more capable students to support less confident peers during group work.
Allow less confident students to work on the activity at their own pace, providing additional time where necessary.
Suggested Assessment Strategies
used strategic whole class or individual questioning
observed student participation during learning activities