Understanding the definition of standing wave

In summary, the conversation discusses standing waves and their properties, including the presence of nodes and the misconception that the wave itself is moving. It is clarified that the wave does not move, but rather the particles or medium through which the wave passes bobs up and down. The concept of constructive and destructive interference is also mentioned as a factor in standing waves. The conversation ends with a link to a helpful visual aid for understanding standing waves.
  • #1
needingtoknow
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Homework Statement



For standing wave, I have read that there are certain points on the wave that don't move at all, nodes. However, for a standing wave the shouldn't the resultant wave have no displacement because we now have two waves on the same rope with the same amplitude and frequency and according to the interference of waves we should add the amplitude of each wave to get the resultant wave. Since each wave has the same amplitude but in the opposite direction, that means the entire wave should not be moving right? Thanks for your help.
 

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  • #2
Watch this:

https://www.youtube.com/watch?v=DovunOxlY1k
 
  • #3
I saw the part on standing waves but it still doesn't answer why isn't the wave simply a straight line. Why does it still bob up and down?
 
  • #4
Am I seeing this diagram correctly. Is the solid line the incident wave and the dashed line the reflected wave?
 
  • #5
needingtoknow said:
Am I seeing this diagram correctly. Is the solid line the incident wave and the dashed line the reflected wave?

I assume the diagram is the standing wave that results from the superposition of the forward and reflecting wave movements.
 
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  • #7
Thanks for your time and effort nsaspook!
 
  • #8
Perhaps needy's understanding is helped by contemplating the following:

Note that what's traveling in a wave is not the particles, air molecules, water molecules or what have you: these make small oscillations around some equilibrium position.

A standing wave isn't bobbing up and down. It's standing. What's bobbing up and down is the what have you's that are passing on some form of energy that brings them away from their equilibrium position.

A traveling wave is something of a misnomer: on the beach there isn't really a whole load of water coming at you. The water itself is making circular motions.
 

1. What is a standing wave?

A standing wave is a type of wave that appears to be standing still, hence the name. It is formed when two waves with the same frequency and amplitude travel in opposite directions and interfere with each other. This results in areas of constructive and destructive interference, creating a pattern that appears to be stationary.

2. How is a standing wave different from a traveling wave?

A standing wave differs from a traveling wave in that it does not transfer energy from one point to another. Instead, it oscillates in place and does not move. In contrast, a traveling wave moves through a medium, transferring energy from one point to another.

3. What is the significance of nodes and antinodes in a standing wave?

Nodes and antinodes are important features of a standing wave. Nodes are points along the wave where the amplitude is always zero, while antinodes are points where the amplitude is at its maximum. These points indicate the areas of constructive and destructive interference, which determine the overall pattern of the standing wave.

4. How is the wavelength of a standing wave determined?

The wavelength of a standing wave is determined by the distance between two consecutive nodes or antinodes. This distance is equal to half of the wavelength of the two interfering waves that formed the standing wave. Therefore, the wavelength of a standing wave is always twice the distance between two consecutive nodes or antinodes.

5. What are some real-life examples of standing waves?

Standing waves can be observed in various real-life scenarios, such as musical instruments, microwave ovens, and seismic waves. In musical instruments, standing waves are responsible for producing specific tones and creating resonance. In microwave ovens, standing waves are used to evenly distribute the energy and cook food. In seismology, standing waves are used to study the Earth's interior and detect earthquakes.

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