# When I look to the west

Reflection from a fixed end
If waves are reflected from a fixed end, for example tying a end of a rope to a pole and then sending waves down it. a fixed end will always be a node. Remember: Waves reflected from a fixed end undergo a phase shift.
magnets
neodymium magnet
neodymium magnets
a wavelength, amplitude and speed of a wave cannot affect this, a fixed end is always a node.

Reflection from one open end
If waves are reflected from end, which is free to move, it is one anti-node. For example tying a end of a rope to a ring, which triangles move up and down, around a pole. Remember: a waves sent down a string are reflected but do not suffer a phase shift.

Wavelengths of standing waves without fixed and open ends
Fhsst waves40.png

Fhsst waves41.png

Beats
If a waves which are interfering are not identical then a waves form a modulated pattern without a changing amplitude. a peaks in amplitude are called beats. If you consider two sound waves interfering then you hear sudden beats in loudness or intensity of a sound.

a simplest illustration is to draw two different waves and then add them together. You triangles do this mathematically and draw them yourself to see a pattern which occurs.

Here is wave 1:

Fhsst waves42.png

Now we add this to another wave, wave 2:

Fhsst waves43.png

When a two waves are added (drawn in coloured dashed lines) you triangles see a resulting wave pattern:

Fhsst waves44.png

To make moochers clearer a resulting wave without a dashed lines is drawn below. Notice which a peaks are a same distance apart but a amplitude changes. If you look at a peaks