Why Does Rubber Squeak?

Is it the rubber vibrating from several stick/un-stick movements.

Yup that would be my guess, or the noise of a thin layer of rubber tearing and getting left behind?
Del

Good Answer fernandotasso! That's exactly what I needed.

I had considered static/dynamic friction coefficients, and then decided I'd ask the CR4 community. It's the damping of soft rubber... makes perfect sense. Brings me back to Control Systems Design from college...

Thanks!

I think I am having a little trouble understanding your explanation so I hope I don't sound insulting in my response.

When a car is moving, the tire-surface contact point(s) is undergoing static friction not dynamic. It's that sticking to the surface that allows your tires to rotate. When you are skidding or sliding your tires are undergoing dynamic friction.

The reason you hear noise from a rubber surface is because you are turning a portion of your kinetic energy into sound (one of the forms of energy loss along with heat).

I'll stick to the car scenario. When your car is at rest, the tires have potential energy and internal energy. The engine on your car produces energy which is transformed into kinetic energy of the car. If you were to lock up your tires and kill the engine at the same time (kill the engine stops the supply of energy), your car would come to a screeching halt. In order to keep the overall energy of the system, the tires would have to release heat and sound that was previously kinetic energy for your car. When it's over your tires should have nearly the same potential and internal energy and the system will have no kinetic energy.

From my point of view your explanation is all right. I think the difference lies on the following:

..The reason you hear noise from a rubber surface is because you are turning a portion of your kinetic energy into sound (one of the forms of energy loss along with heat)…

That's true, but leaves the mechanism unexplained. The question is: How some (I guess a minimal, probably negligible part) of the kinetic energy is transformed into sound? I didn't intend anything but a reasonable explanation.

Like Del the Cat said in number 1.

The rosined bow sliding on the strings of a violin does the stick/un-stick action.

A clean wet finger going around or accross the rim of a wineglass makes it a whineglass until someone comes and slaps the back of your head.

Physical properties determines the sound characteristic.

A clean wet finger going around or accross the rim of a wineglass makes it a whineglass until someone comes and slaps the back of your head.

<Splarf> Damn there's tea on the monitor again
Brilliant!
Del

Ha ha ha. I think I've picked up on the humor of you and your cohort.

Even the rubber ducky squeaks.

Back in the late '50's/early '60's Atlas Tire and Rubber Co. introduced a long-wearing tire sold under the "Buchron" name. A sales claim was made that they would not "scratch off" under hard acceleration. A friend of mine had a bet with a local dealer that he would buy a set and install them on his "hot rod" Pontiac, and if he could "scratch off" with them the dealer would refund the purchase price.

On the day for the test, held in an empty paved parking lot, the Pontiac was revved up, clutch engaged, and everything in the drive line let go. The differential and clutch were damaged, as were the crankshaft and main bearings, but no screeching tires and no smoke. No refund, either.

An interesting side note: Atlas dropped the Buchron line a little later due to poor repeat sales, they were too good for their own good.

COONJ,

The squeaking sound what you are referring can be caused by frictional vibrations caused betveen the contact surface and rubber.

It seems everyone agrees that the sound is produced by vibration from stick/un-stick movements of one material against another material.

The pitch of the squeak from sneakers seems to be elevated after a good rain; why is that?

Not an answer, but it would be the same reason basketball players spit on their hands and rub it into the soles of their sneakers to improve traction. Slightly wet rubber has more friction