(WVS) Waves Module Overview

Waves Module Overview

"Catch the wave, Do the wave, Feel a wave" are idioms you have most likely heard. "Catch the wave" refers to a new trend or actually riding an ocean wave. "Do the wave" refers to a rallying activity fans participate in to encourage a sports team. "Feel a wave" refers to an awareness of an emotion overtaking you. However, what is a wave in the simplest, most concrete terms?

In this module, you will recognize that all waves transfer energy. You will compare and contrast electromagnetic waves and mechanical waves. You will apply wave interactions to familiar experiences like the sound change heard when an ambulance speeds by. You will explore how the speed of sound is affected as it travels through a solid, liquid, and gas. We are bombarded by waves, both light and sound, constantly throughout our day. Let's dive right in to learn more about these waves!

Essential Questions

• How is energy transferred by waves?
• How do the properties of waves influence what our eyes and ears actually sense when seeing different colors and hearing distinct sounds?
• How do waves interact with various types of matter as well as other waves?
• Compare and contrast electromagnetic and mechanical waves.
• How does moving the source of the wave change the properties of the wave?

Key Terms

1. Waves – are disturbances that repeat the same cycle of motion and transfer energy through matter or empty space.
2. Mechanical waves – a wave that requires a medium. Transfers energy as the particles in the medium move (vibrate) up and down or back and forth as the wave travels through it.
3. Electromagnetic waves – a wave that is capable of transporting energy through the vacuum of outer space. Electromagnetic waves are produced by a vibrating electric charge and as such, they consist of both an electric and a magnetic component.
4. Wavelength - the distance between two consecutive crests or troughs of a wave.
5. Amplitude - the maximum amount of displacement of a particle on the medium from its rest position. In other words, the amplitude is the distance from rest to crest or rest to trough.
6. Frequency - the number of complete waves, or cycles of oscillation, in a given period of time. The unit for frequency is Hertz, which is equal to one wave per second.
7. Period - the time it takes to complete one full cycle.
8. Speed – measures how fast a wave is moving. In electromagnetic waves, the speed is directly proportional to the frequency and wavelength of the wave according to the relationship v = f λ.
9. Photons – tiny packets of energy
10. Reflection - occurs when a wave hits an object that it cannot pass through or when it reaches the boundary of the medium of transmission. Both situations involve the return of the wave as it bounces off the object or medium boundary.
11. Refraction - takes place when a wave passes from one medium into another at an angle and bends (changes direction) due to a change in speed.
12. Diffraction – results when a wave passes through a hole or moves past a barrier and spreads out in the region beyond the hole or barrier.
13. Interference – occurs when two or more waves arrive at the same point at the same time. As a result, they combine to produce a single wave. This new wave will have different properties from the two waves that composed it.
14. Constructive Interference – a type of interference that occurs at any location along the medium where the two interfering waves have a displacement in the same direction resulting in a larger amplitude.
15. Destructive Interference – a type of interference that occurs at any location along the medium where the two interfering waves have a displacement in the opposite direction resulting in a smaller amplitude.
16. Doppler Effect – the phenomenon of a change in the observed frequency of a wave, sound or light, that occurs when the source and observer are in motion relative to each other. For example, when a sound source moves toward a listener, the pitch, or apparent frequency, of the sound increases. This is because the sound waves are compressed closer together and reach the listener with a higher pitch. As the sound source passes by the listener and moves away from the listener, the same sound waves are stretched farther apart. This results in a decrease in the pitch, or apparent frequency.
17. Crest - the highest point within a cycle of a wave.
18. Trough - the lowest point within a cycle of a wave.
19. Hertz - a unit of frequency equal to one cycle per second.
20. Longitudinal wave - a wave in which the particles of the medium are displaced in a direction parallel to the direction of energy transport.
21. Medium - the matter a wave travels through (solid, liquid, or gas).
22. Pitch - the distinctive quality of a sound, dependent primarily on the frequency of the sound waves produced by its source. (for example, high pitch or low pitch)
23. Transverse wave- a wave in which the particles of the medium are displaced in a direction perpendicular to the direction of energy transport.
24. Compression - a point on a medium through which a longitudinal wave is traveling that has the maximum density. In other words, it is a region where the coils are pressed together in a small amount of space.
25. Rarefaction - a point on a medium through which a longitudinal wave is traveling that has the minimum density. In other words, it is a region where the coils are spread apart, thus maximizing the distance between coils.
26. Electromagnetic Spectrum - the continuous range of frequencies that electromagnetic waves exist. The longer wavelength, lower frequency regions are located on the far left of the spectrum, and the shorter wavelength, higher frequency regions are on the far right.
27. Radio waves – electromagnetic waves that have the longest wavelengths, lowest frequency, and least amount of energy in the electromagnetic spectrum.
28. Microwaves – electromagnetic waves found at the higher frequency end of the radio waves on the electromagnetic spectrum.
29. Infrared Waves – electromagnetic waves just beyond the visible spectrum of light.
30. Visible Light Waves – the portion of the electromagnetic spectrum that we can see.
31. Ultraviolet Waves – electromagnetic waves that have shorter wavelengths than visible light.
32. X-rays – electromagnetic waves that have higher energy and much shorter wavelengths than ultraviolet light. Scientists usually refer to x-rays in terms of their energy rather than their wavelength.
33. Gamma Rays – electromagnetic waves that have the smallest wavelengths and the most energy of any wave in the electromagnetic spectrum.

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