# PS.8 - Waves

The student will investigate and understand the characteristics of sound waves. Key concepts include

a) wavelength, frequency, speed, amplitude, rarefaction, and compression;

b) resonance;

c) the nature of compression waves; and

d) technological applications of sound.

Bloom's Levels:  Analyze; Understand

### BIG IDEAS

• Waves transfer energy without transferring matter.

• I can explain why my friend's voice sounds different when I'm under water.
• I can explain a crystal glass may break while someone is singing.
• I can explain how sound how sound is a part of every aspect of my life.

### UNDERSTANDING THE STANDARD

• Sound is produced by vibrations and is a type of mechanical energy. Sound travels in compression waves and at a speed much slower than light. It needs a medium (solid, liquid, or gas) in which to travel. In a compression wave, matter vibrates in the same direction in which the wave travels.
• All waves exhibit certain characteristics: wavelength, frequency, and amplitude. As wavelength increases, frequency decreases.
• The speed of sound depends on two things: the medium through which the waves travel and the temperature of the medium.
• Resonance is the tendency of a system to vibrate at maximum amplitude at certain frequencies.
• Reflection and interference patterns are used in ultrasonic technology, including sonar and medical diagnosis.
• The speed of sound depends on two things: the medium through which the waves travel and the temperature of the medium.
• A compression (longitudinal) wave consists of a repeating pattern of compressions and rarefactions. Wavelength is measured as the distance from one compression to the next compression or the distance from one rarefaction to the next rarefaction.

### ESSENTIALS

In order to meet this standard, it is expected that students will

a)  determine the relationship between frequency and wavelength.

analyze factors that determine the speed of sound through various materials and interpret graphs and charts that display this information.

model a compression (longitudinal) wave and diagram, label, and describe the basic components: wavelength, compression, rarefaction, and frequency.

b)  identify examples illustrating resonance (e.g., musical instruments, Tacoma Narrows Bridge, crystal stemware).

d)  describe technological applications of sound waves and generally how each application functions.

design an investigation from a testable question related to sound. The investigation may be a complete experimental design or may focus on systematic observation, description, measurement, and/or data collection and analysis.

### KEY VOCABULARY

wavelength, frequency, speed, amplitude, resonance, longitudinal wave, medium, compression, rarefaction

Updated: Jun 29, 2018