GRADE LEVEL: 6-9
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OVERVIEW: By doing the wave as seen at various sporting events, students will explore waves in terms of their properties, frequency, amplitude, wave velocity and wavelength. Students will then describe the behavior of waves as they interact.
PURPOSE:This lesson is designed to engage all students into the learning process by relating an everyday and familiar occurrence to the properties of waves. This lesson can also be used as background knowledge before continuing to the concepts covered on the RADIO web site.
OBJECTIVES: At the conclusion of this lesson, the learner will be able to:
Define period, frequency, amplitude, wavelength, and wave velocity
Describe the behavior of wave interactions
- Chairs for each student, placed into a circle.
INTERNET SITES: http://www.bro.lsu.edu/radio
- Once chairs are set up, with no gaps, allow students to do a few practice waves. Two students should stand outside of the circle in order to gather information for computing frequency. One student should have a stopwatch, the other student will count the waves.
- Have students identify all parts of a wave. (crest, rest position, trough) Then have the students identify these positions on their human wave. They will notice that there is no trough.
- Have the students do more waves, but this time have them incorporate a trough. (One student will stand with raised hands, then kneels with hands lowered. The next student raises his or her hands while the first student is kneeling. Depending on your age group, this may take a few practice runs.)
- Once your wave has successfully gone around, have students identify the wavelength, crest, and amplitude.
Wavelength - distance from someone with their hands up to the next person with their hands up
Crest - distance from person with hands at rest to hands up
Amplitude - difference between their height when standing and kneeling. An average of the amplitude is taken because of the varying heights of the students.
- Have students identify the wave medium (themselves) and identify the wave as a transverse wave.
**Because of the difficulty of doing the wave by standing and kneeling, you may want to go back to the original sitting and standing wave for the remainder of the activity.
- Students should be asked to define the period of their wave - the time it takes one student to stand and sit back down.
- Have the time keeper outside of the circle calculate the period of the wave as students do the wave.
- Ask students to demonstrate how they would double the period – students should go twice as slow. Then ask students to cut the original period in half – students should go twice as fast.
- Students should be asked to define their frequency. Then have the timekeeper time the students doing the wave for 30 seconds while the other student outside the circle counts the number of waves that go by.
- Ask the students to double the frequency - they should double their speed. Then ask them to cut the frequency in half. Because this requires the cooperation of everyone in the circle, many attempts may be necessary to achieve the desired results.
- To finish up the activity, we discuss what would happen when two waves interact.
Possible quiz questions:
- How is the period affected by speed?
- How is the frequency affected by speed?
- What happens to the period when the frequency increases?
- What is the relationship between speed and frequency?
- How is wavelength related to frequency?
- What happens to amplitude when a crest and trough collide?