1. The Behavior of Mechanical Waves

6. Mechanical Waves
Starting of easy, a wave is a repeating disturbance that transfers energy from one place to another.
A mechanical wave is a wave that travels through a medium(a material through which energy of the wave moves from one place to another) due to the motion of matter.
Here’s an example of a mechanical wave like sound:
When a book is slammed on the table, it created disturbance in air particles that creates sound waves from the book to your ears. In this case, the air is the medium, which is the material in which a wave needs to move from one place to another.

8. Sound, Media, and Wave Speed
Some wave properties depend on the medium that the wave is traveling through. Each medium also has properties that determine how its particles move
A sound wave is a longitudinal mechanical wave caused by the vibration of particles as the wave travels through its medium.
Sound waves often travel through solids, liquids, and gases(their medium). And for this reason, they can be used to observe how a medium affects a mechanical wave’s properties.
1) What does the pitch of the sound wave refer to?
2) How is the frequency of a sound wave related to its pitch?

11. Properties of Sound
The features of soundwaves are related to the properties of mechanical waves.
The volume of something is related to its amplitude, meaning that if you two sound waves that are identical expect for the amplitude, the sound wave with the higher amplitude will sound higher
The pitch however is related to its frequency, meaning that if you were to hear a high-buzz, the sound waves that were to reach you ear would have a high frequency

17. Mechanical Waves Spread Out
Mechanical waves spread out to different directions through a medium over time.
For example, sound waves in the air spread out as a sphere around the original disturbance.
And as this waves spreads further out on larger areas, the amount of energy in any one part of the wave decreases.
In a simpler explanation, the reason that faraway sounds are so quiet is because less energy is reaching the listener.

19. Absorption
Mechanical waves cause particles in a medium to move, bump into each other, and transfer energy.
During this movement, some of the wave’s energy is converted to thermal energy by friction.
This is where absorption comes and converts the energy.
When energy is absorbed by a medium, the medium gains thermal energy and the wave loses that energy.

21. Absorption
Absorption can vary based on the frequency of the wave. Its very simple
The higher the frequency is, more energy will be lost to absorption. And the lower the frequency is, then less energy will be lost to absorption.
This is similar to when you rub your hands together.
Rubbing your hands against each other slowly wont generate enough thermal energy to warm them, but if you rub them quickly, it will generate enough thermal energy to warm your hands.

23. Transmission Consider that you hear a sound coming through a wall.
A sound wave would travel through air, moved through the wall, and then travelled back through the air to later reach your ear.
When a mechanical wave finds a new medium, it can transfer into that medium.
This process is called transmission

26. Refection
Reflection
When a wave finds a new medium, it doesn’t always transmit to it. Instead it can reverse its direction and head back to its original medium.
Partial Transmission and Reflection When a wave encounters a boundary between two different media, it neither entirely transmits nor reflects. Instead, it does both.

34. https://youtu.be/Ude8pPjawKI