Wave Properties



Believe it or not, but waves are everywhere. There are sound waves, ocean waves, heat waves, light waves and many other types of waves. Waves have many characteristics and properties that make them similar to other waves and unique to others. Many wave behaviors come from the fact that two waves can exist, in the same place, at once. When waves are traveling they usually encounter mediums (boundaries). The wave either bounces off of this medium or goes through it. When waves go through these boundaries they sometimes change direction. A mechanical wave’s speed depends on the medium it is passing through, unlike water, air, and waves of a spring whose speed is determined by temperature, depth of water, and the spring’s mass per unit length.

The wave that strikes the boundary is called the incident wave. If the waves is able to be reflected backwards, then this new wave is called a reflected wave. When the wave strikes a wall it’s reflected wave is sent back with almost the same amplitude as the pulse of the incident wave.

 

 

If the wave is mechanical (coming form a spring) then the reflected wave is inverted. If a reflected wave meets an upcoming incident wave, the displacement of the waves is algebraically summed up. This is called the Principle of superposition. It basically states that two waves can come together to form a new wave.

The green wave is the new wave.

If the waves are headed in opposite direction they can form a wave of greater or less amplitude. This new wave is called interference. The green wave in the previous example would be an interference. There are two kinds of interferences you should know. There is a destructive interference, which is an interference that is caused by equal but opposite waves. They meet in the same location and have zero displacement, this causes a the creation of a point that doesn’t move at all. This point is called a node. There is also constructive interference. It occurs when wave’s displacement is in the same direction. It causes one wave that is greater than both of the original waves. The point in a constructive interference where the displacement is greatest is the anti node. The antinode does not move and continues to be the point with the biggest displacement. When two waves

 

 

 

 

 

 

 

 

There are also such things as continuous waves and standing waves. When a transmitted wave moves into a new region, it can either slow down, speed up, or stay the same. If the new region has a higher velocity then the amplitude and wavelengths. This is also true if a wave enters a region with a lower velocity. It’s wavelength and amplitude become smaller. A standing wave is a wave that resonates. As the wave resonates, many vibrations happen within the wave and it makes the wave appear to be standing still.

The waves will have vibrations in between the spaces and appear to be standing still.

Usually when something hit’s a barrier it bounces back, but waves bend around the edge of the barrier. This is called Diffraction. This also happens when waves meet a small obstacle, the wave will bend around it, creating waves behind it. Suppose there are two small holes in the barrier. The waves will go through the holes and come out as circular waves. The two waves will eventually meet each other and it will be constructive interference, resulting in bigger waves.

 

Things you should know

Vocabulary

Equations