SHS2 Physics · Semester 1 Week 19: Waves

Lesson notes

Learning Objectives

Indicator: 2.2.2.LI.3 - Explain how an echo comes about and apply the phenomenon in the determination of the depth of rivers.

By the end of the lesson, learners can:

Explain how an echo is produced, using the concepts of reflection of sound and the time interval between the original sound and its reflected return
State the condition necessary for a distinct echo to be heard (minimum distance of about 17 m from a reflecting surface in air at room temperature)
Derive the echo equation, speed = (2 × distance) / time, from the relationship between speed, distance, and time
Calculate the depth of a river or the distance to a reflecting surface using the echo equation
Solve word problems that apply the echo principle to practical situations such as echo sounding and depth measurement

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Curriculum details

Strand: Energy (Strand 2)
Sub-strand: Waves (2.2)
Content standard: 2.2.2.CS.2 - Demonstrate knowledge and understanding of sound waves. 2.2.2.LO.2 Using the property of reflection of sound and the phenomenon of resonance to give an account of how the speed of sound can be determined.
Indicator: 2.2.2.LI.3 - Explain how an echo comes about and apply the phenomenon in the determination of the depth of rivers.
Suggested placement: Semester 1, Week 19 (Week 19 of the year)
Our suggestion, laid out in curriculum order across three terms of twelve weeks. NaCCA does not fix the week, so follow your school's scheme of learning.
Curriculum reference: NaCCA curriculum document, p. 114

Exemplars (from the NaCCA curriculum)

Think pair share: Using think pair share lets learners employ the concept of relating speed to distance and time to establish an equation for the speed of sound as far as a reflection of sound.
Foster collaborations that broaden students' exposure to diverse physics-related career paths and role models.
Assessment (2.2.2.AS.3). The document marks these depth-of-knowledge levels for this indicator: Level 3 Strategic reasoning.
Teaching and Learning Resources:
- Audio-visuals
- Internet
- Projectors
- YouTube
- Interactive laboratory virtual
- Slinky
- Sonometer
- Guitar, piano
- Frequency/signal generator
- Resonance tube set up