Standing Waves: Understanding the Basics

In summary: It's not clear what the author is trying to say. In summary, a standing wave is a pattern of oscillations that appears to stay put, because it has a wave dynamical.
  • #1
deltafee
10
0
Hi,
I am working on my notes dealing with standing waves and I was wondering would a graph of the equaion y(x,t)= 2Acos(ωt)sin(kx) just a regular wave? Also I was wondering why are standing waves called standing waves. I am sorry if this is the wrong forum.
 
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  • #2
Also I was wondering why are standing waves called standing waves.

They're called standing because they stay put, kind of. The counterpart of the standing wave is the traveling wave, because it isn't standing, it's walking, or traveling in some direction, either left or right in the typical 2-d plane they're represented in.

I said "kind of" above, because standing waves only appear to be standing because of the wave dynmaics. That is, what you have is one wave traveling to the right while another wave is simultaneously traveling to the left. The end result is a superposition or interference pattern that sets up apparent stationary oscillations which represent certain harmonics of a fundamental frequency depending on the boundary conditions of the system. Those being the length of, say, a rope that two people are shaking at either end.

As far as your equation above, that looks like a traveling wave equation to me, a standing wave equation specifies one wave traveling in each direction. However, I haven't double checked that.
 
  • #3
If you define "wave" as a function that satisfies the wave equation, then your expression of the standing wave is considered "a wave".

If you define "wave" as a function that carries the real power, then your expression is not a wave. No power is transported from one place to another.

It is worth noticing that standing wave also forms if the power carried by the forward traveling wave is not equal to the power carried by the backward traveling wave.

Personally, I think "wave" is used loosely here.
 

1. What are standing waves and how are they formed?

Standing waves are a type of wave that forms when two waves with the same frequency and amplitude travel in opposite directions and interfere with each other. This causes the wave to appear stationary or "standing" instead of moving.

2. What are the key characteristics of standing waves?

The key characteristics of standing waves include nodes, antinodes, and wavelengths. Nodes are points on the wave that do not move, while antinodes are points that experience the most movement. Wavelengths are the distance between two consecutive nodes or antinodes.

3. How do standing waves differ from traveling waves?

Standing waves differ from traveling waves in that they do not transfer energy from one point to another. Instead, they oscillate in place and do not propagate through a medium. Additionally, traveling waves have a distinct direction of movement, while standing waves do not.

4. What are some examples of standing waves in real-world applications?

Standing waves can be found in a variety of real-world applications, such as musical instruments, microwave ovens, and seismic waves. In musical instruments, standing waves are responsible for creating distinct tones and harmonics. In microwave ovens, standing waves are used to evenly distribute heat. In seismology, standing waves can be observed in the Earth's crust during earthquakes.

5. How are standing waves important in understanding the behavior of light and matter?

In the field of quantum mechanics, standing waves play a crucial role in understanding the behavior of light and matter. The wave-particle duality of light and matter can be described using standing waves, and the quantization of energy levels in atoms can also be explained through standing wave patterns. Additionally, standing waves are essential in understanding the concept of resonance, which is important in many technological applications.

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