Are only longitudinal waves formed by air particles?

Question

Can only longitudinal waves form in air or can transverse waves form too? If yes,how?And if not, why not? This is confusing me so much. Please give me a full description of how waves form in air.

Answer 1

Hi Yoshani, 

 

In order to answer your question I'll need to give you a brief explanation of what longitudinal & transverse waves are/ how they work: 

 

1) Longitudinal waves are waves in which the particles of the medium move in a direction parallel to the direction the wave itself is moving. For example, imagine you have a slinky stretched out on the floor right in front of you. You grab some of its coils in your hand and then quickly thrust your hand forward, sending a pulse. That pulse moves in one direction, from left to right while the coils of the slinky, one-by-one, move from left to right as well. Thus, your particle motion (movement of the coils) is the same as your wave motion (direction of the pulse).

 

2) Transverse waves are a bit different. With transverse waves, the particles of the medium move in a direction perpendicular to the direction the wave moves. Let's think of a long stretch of rope. You're holding one end of the rope and your friend standing right in front of you is holding the other end. Quickly you snap your hand that holds the rope up and then down again. When you do this, you're once again sending a pulse that travels from left to right, only this time the small sections of rope (or particles) are moving up and down a.k.a. perpendicular to the wave motion. 

 

Longitudinal waves can occur in air. Sound waves are a good example of this type of wave. When sound comes out a speaker, each air particle pushes on its neighboring particle and rebounds back a bit as a result. The air particles shift, one-by-one in the same direction the wave. 

 

Transverse waves, on the other hand, don't travel through air or any other gases. But, they do travel through solids. With solids, you have a ton of atoms densely packed together. Being so close to one other, they exert forces on each other. When an atom is in a particular location (called the equilibrium location) , the forces coming from all directions balance one another out. But when an atom is jolted out of its equilibrium location by a disturbance, it then pulls its neighbors out of their equilibrium locations as well before it's pulled back into place. The result of all this happening is a transverse wave (check out an animation of a transverse wave and you'll see what I mean). In liquids and gases (which are less dense), atoms have no equilibrium location. They just freely move past each other. This is the reason why transverse waves don't travel through these types of mediums. 

 

Whew, that was a long one. Hope this cleared up all of your questions. Feel free to contact me if you need some more help or clarification! 

 

Answer 2

Yes, only longitudinal waves, since air cannot support transverse waves.

In order to support transverse waves, air would have to be tear-able like a bed sheet.

Technically, air cannot support shear stresses.