# PS.9 - Wave Characteristics & Applications

The student will investigate and understand the characteristics of transverse waves. Key concepts include
a) wavelength, frequency, speed, amplitude, crest, and trough;
b) the wave behavior of light;
c) images formed by lenses and mirrors;
d) the electromagnetic spectrum; and
e) technological applications of light.

Bloom's Levels:  Analyze; Understand

Adopted: 2010

### BIG IDEAS

• The wavelength and frequency of a light wave gives its observable color.
• Mirrors and lenses can distort an object's size, shape, or orientation.
• Waves have a variety of applications, including communication.

• I can explain how waves vary.
• I can explain how mirrors in stores trick me.
• I can explain how glasses help me see better.
• I can explain why x-rays can show my bones, but other waves cannot.
• I can describe how barcode scanners work.

### UNDERSTANDING THE STANDARD

• Visible light is a form of radiant energy that moves in transverse waves.
• All transverse waves exhibit certain characteristics: wavelength, crest, trough, frequency, and amplitude. As wavelength increases, frequency decreases. There is an inverse relationship between frequency and wavelength.
• Radiant energy travels in straight lines until it strikes an object where it can be reflected, absorbed, or transmitted. As visible light travels through different media, it undergoes a change in speed that may result in refraction.
• Electromagnetic waves are arranged on the electromagnetic spectrum by wavelength. All types of electromagnetic radiation travel at the speed of light, but differ in wavelength. The electromagnetic spectrum includes gamma rays, X-rays, ultraviolet, visible light, infrared, and radio and microwaves.
• Radio waves are the lowest energy waves and have the longest wavelength and the lowest frequency. Gamma rays are the highest energy waves and have the shortest wavelength and the highest frequency. Visible light lies in between and makes up only a small portion of the electromagnetic spectrum.
• Plane, concave, and convex mirrors all reflect light. Convex mirrors diverge light and produce a smaller, upright image. Concave mirrors converge light and produce an upright, magnified image if close and an inverted, smaller image if far away.
• Concave and convex lenses refract light. Convex lenses converge light. Concave lenses diverge light. †
• Diffraction is when light waves strike an obstacle and new waves are produced.
• Interference takes place when two or more waves overlap and combine as a result of diffraction.

### ESSENTIALS

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

a)  model a transverse wave and draw and label the basic components. Explain wavelength, amplitude, frequency, crest, and trough.

b)  describe the wave behavior of visible light (refraction, reflection, diffraction, and interference).

design an investigation to illustrate the behavior of visible light – reflection and refraction. Describe how reflection and refraction occur.

c)  identify the images formed by lenses and mirrors.

d)  compare the various types of electromagnetic waves in terms of wavelength, frequency, and energy.

e)  describe an everyday application of each of the major forms of electromagnetic energy.

### KEY VOCABULARY

reflection, refraction, diffraction, interference, electromagnetic spectrum, electromagnetic radiation, transverse, gamma waves, x-rays, ultraviolet, visible light, infrared, radio waves, microwaves

Updated: Jun 29, 2018