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Building Your Own Crystal Radio (continued)
Materials:
For a class set of 30 students.
• 10 Empty Paper Towel Roll or Sturdy Water Bottle/Shampoo Bottle
• 25 feet of Aluminum Foil
• 2 Wire Cutters
• Markers
• Tape
• Scissors
• 10 Germanium Diode (1N34A)
• Hook Up Wires (22 gauge)
• Magnet/Copper Wire (28 gauge)
• 30 Alligator Clips
• Piezoelectric earphone or Speaker/Rechargeable Power Speaker
• 100 Brass Fasteners
• Printed Student Worksheets
• Ruler
• Graph Paper
• 10 Cardboard Sheets
• Computer for Research
Pacing Notes:
This lesson will take about 3–5 days to complete for a rough estimate of about 150 minutes or more. This is assuming each class
period is about 50 minutes long. If you do not want to spend this much time on the lesson you can assign part of the research for
how radio works as a homework assignment.
Day 0—Students will discuss the different ways that communication has occurred in the past and modern society (5 minutes).
Students will then have about 25 minutes to research and create a short poster about how cell phones work in a rural versus urban
area.* Optional lesson.
Day 1—Students will start researching crystal radio and how they work. They will sketch a design of how they would like to build
their crystal radio along with what materials they need.
Day 2 & 3—Build and finish making the crystal radio. Students will demonstrate if their crystal radio works to the teacher.
Students will also provide a short presentation to demonstrate their understanding of how information is transmitted through
electromagnetic radiation to encode a signal.
Pre-Activity Assessments:
Classroom Instructions Introduction:
Warm Up: 5–8 minutes.
Have students take out warm up sheet to complete the questions below:
1. How do people communicate in the past?
2. How do we communicate now?
3. Do you think there are any places in the United States where there are no cell phones or Wi-Fi use? Why or why not?
Share Aloud: As students are answering questions, you can finish taking attendance. Walk around the classroom to observe and
possibly comment on what students are writing on their paper.
Have students think-pair-share their work with their shoulder partners or someone close by. Use equity cards to randomly choose
a few students to share their answers to the class. If time permits, have students briefly discuss what they think are pros and cons
for the old versus the modern forms of communication.
