Wave Interactions

Waves often interact with materials in the environment in different many ways. These interactions can affect the environment in a number of ways. Some of these wave interactions are caused by some of the properties that some waves have. An example of this would be the wavelength of a sound wave as if the wavelength is short, the wave might not be able to reach a certain source that might be the ear, therefore not allowing us to hear the sound from our ears. Listed below are some of the interactions of waves.


Interference is when two waves superpose each other (On or above each other) that are very similar. A factor that creates inference is frequency. If two waves have the same or very similar frequency as each other, theres a chance that this will cause an interference. When two waves create an interference, the amplitude will increase or decrease depending on the conditions. Inference can interact with the environment as the amplitude changes therefore meaning if its a sound wave, the sound will either increase or decrease in the sound (louder or quieter).

An example of Inference.


Reflection is when the direction of the waves leads the waves to a certain boundary that bounces the waves back to the source of the waves. This creates reflection. A property that can produce reflection is wavelength. If the wave isn't long enough, it may not reach that boundary that causes it to reflect. An example of reflection is light waves traveling in the direction of a lake, therefore making the light wave reflect off the lake back at the source of the light waves. An Other example of reflection of waves include standing waves reflecting off each other as they travel back and forth. Frequency can also affect reflection as well, more frequency produces more reflection. Reflection can interact with the environment as they can make an image reflect off a certain surface like a lake.

A demonstration of reflection.


Refraction is when a wave changes its direction. Refraction is mainly caused by a change in speed in the wave. Another factor that can contribute to refraction is when the wave passes through a certain substance at any angle besides 90 and 0 degrees (straight or right-angled direction). Refraction can occur with any wave as long as these factors occur. Refraction can interact with the environment as it can bend certain materials. An example of refraction are waves causing water drops to bend. Below is an image explaining the example visually.


Mentioned before, speed is a main contribution in creating refraction. A property that is a factor in creating refraction is period as that measures the amount of time the wave takes to travel a certain distance.

Refractive Index

Refractive Index is the measurement of speed of light in a substance. It's measured as a ratio as the formula is listed below:

Speed of light in vacuum/speed of light in medium

Speed of light usually travels faster in a vacuum than light would travel in a material. This is because the air is more dense and has more space to travel in.

Law of Reflection

The law of reflection is basically when light rebounds off a surface like a mirror. This law consists of three main properties, the reflection ray, the incidence ray and the normal line. The incidence ray is when the light travels in a direction off a mirror and the reflection ray is the direction the light reflects of the mirror. The normal line is an imaginary line that is in the middle between the two ray's. Each ray will have an angle. To work out the reflection ray's angle, you must subtract the normal line's angle (90 degrees) with the ray of incidence's angle. The formula is below.


Reflection can be different though in different conditions. In a condition like water, the light will reflect in a different angle because their is different density to say air. This is why sometimes when we got to reach for something we see in the water and its in a different spot. Here is an example.


Diffraction is when a wave encounters an obstacle in its path. Properties that can contribute to diffraction is the wavelength as the wave may be long enough to reach an object. Other factors that may contribute to diffraction is the actual path the wave is travelling in, leading the wave to the object. Diffraction can interact with the environment by affecting certain objects made of atoms. An example of diffraction is ocean waves passing through a buoy, the waves bend around it but also affects it by making it move. Diffraction can occur with all waves as long as the factors occur.