Is this an accurate description of standing waves?

  • #1
Ytfeza
Hi all, is my description below a reasonable attempt in explaining how a standing wave forms?
The main part I am a bit confused as to how to explain is why the antinodes move up and down. Thanks!


A standing wave is formed when energy of a wave of the right frequency is trapped in the system causing resonance to occur. This occurs when there are two progressive waves with the same frequency approaching each other in opposite directions (reflected wave superimposing with the incident wave). As the two waves superimpose there will be points in the standing wave where the two waves are always antiphase (out of phase by pi radians), so they will destructively interfere producing nodes (always nodes). In the middle of two adjacent nodes the waves will be in phase so constructively interfere to produce antinodes with max amplitude. Between a node and an antinode the amplitude varies depending on how much amplitude from the two waves constructively add together. Between two nodes the antinode's amplitude changes from max to min (up/down) as particles passes through the equilibrium position because as the two waves move their phase begins to shift, so between the two nodes constructive and destructive interference can occur. When constructive occurs the particles at the antinode are at a maximum displacement (either + or -), and when it reaches the equilibrium (same position as the stationary nodes) the two progressive waves are out phase and destructively interfere. Hence, the particles in the standing wave have the most potential energy when they are at a maximum amplitude and most kinetic when passing through the equilibrium.
 

Answers and Replies

  • #2
543
146
Hi all, is my description below a reasonable attempt in explaining how a standing wave forms?
The main part I am a bit confused as to how to explain is why the antinodes move up and down. Thanks!

Check out this animation:
You can use the YouTube Settings button to slow it down, which may help make what's happening clearer.
 
  • #3
Frenemy90210
Check out this animation:
You can use the YouTube Settings button to slow it down, which may help make what's happening clearer.

Does anyone have a link to that website with animation ?
 
  • #4
davenn
Science Advisor
Gold Member
9,574
8,633
Does anyone have a link to that website with animation ?

it's on youtube

right click on video and select copy video url
 
  • #5
Frenemy90210
it's on youtube

right click on video and select copy video url

No, I meant the website ( or tool) that is shown in the youtube video.
 
  • #7
sophiecentaur
Science Advisor
Gold Member
2020 Award
26,580
5,589
The main part I am a bit confused as to how to explain is why the antinodes move up and down.
The polarity of a travelling wave alternates each side of zero so the sum of two waves (the standing wave) will do the same where there is constructive interference.
It is very important that you learn to search for this sort of information yourself. A few attempts at a google search (with trial and error selection of different terms) will give you more hits than every you can get with individual recommendations from PF. If you are looking for animations then the Videos button on the google search will give you many suggestions. the same applies to Images.
 

Related Threads on Is this an accurate description of standing waves?

  • Last Post
Replies
3
Views
707
  • Last Post
Replies
5
Views
2K
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
0
Views
1K
  • Last Post
Replies
5
Views
2K
  • Last Post
Replies
1
Views
717
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
11
Views
2K
  • Last Post
Replies
3
Views
794
  • Last Post
4
Replies
76
Views
16K
Top