Noise in the knee

Apart from my 10k walk/run exercise, I had a look at Krista's site and decided to try the beginner's routine.
While squatting, though, with no extra weight, I hear a little noise coming from my knee.
Do you have an idea of what that could be?

If you're not having any pain, one common harmless noise is gas bubbles popping, similar to cracking knuckles. Age or mild arthritis can result in crepitus, a crackling or grinding from some roughening of the surfaces (which to me sounds rather like sand in the joint of a lawn chair).

Popping or grinding can also result from damage to cartilage or ligaments, but that is usually accompanied by pain.

Thank you very much!

I have that... I broke my knee years ago and its never been the same. I have thinned cartiledge in my left knee. It always pops and grinds. Losing weight has helped with the pain, but I still have nerve damage and numbness.
I am amazed I lived with it for so long pushing 300..

My left knee makes a popping noise at times. Mine is due to an injury and doesn't always pop. Sometimes I can get outside and start walking and it pops every step and it might stop after about 15-20 minutes. Most of the time it doesn't pop though. I don't know why it pops sometimes and doesn't others.

Hope someone can answer your question,

...

Most joints make noise when they move. If you happen to have access to a stethescope put it to a joint and move your joint through its range of motion and you will hear noise. My knees have cracked since I was 12, and I was deffinately not over weight then

If there is no pain, and you don't seem to have any reduction in range of motion, you are probably hearing fluid being pushed out of the joint (normal), ligaments moving over bones (normal), cartilage being compressed (normal). If there is pain, you feel like you can't do something because of some sort of restriction, then I would go see your doctor.

Knees take a lot of wear and tear. Being properly hydrated will help your joints with being able to maintain proper nutrition in them.

Take this with a grain of salt from me, as I have never tried it, but I have heard some people say Glucosamine helps tremendously with joints, it apparently helps improve cartilage, and ligaments. If there is anyone in the group who has experience with it, maybe they can comment on it.
who is not a doctor, but has a background in anat and phys

Hmmm have you had a doctor look at it?? It could be many things...
What type of noise?