[stana (OP)]

Okay, I was wondering the other day, I was told that my body is held tightly together. that there is alot of pressure on me. so i was thinking

Howcome all This pressure doesn't kill me, but  knife can go straight through me and kill me?

Also

I was sitting at my desk in School the other day, and i turned my neck awkwardly, and my neck clicked, i can do this with my fingers, and my back. What is this? I was told STOP IT!, because i would get arthritis. is this true?

This question has nothing to do with science, but your the only guys i think that would know. If i don't like a female, I'm sexist, if i don't like someone of a different race, I'm a racist. So, what is it if i don't like your shoes? Shoeist? Or anything else, is there a word for it?


Thanks guys

[JimBob]

Okay, I was wondering the other day, I was told that my body is held tightly together. that there is alot of pressure on me. so i was thinking

How come all This pressure doesn't kill me, but  knife can go straight through me and kill me?

Doh, beats me! Where are the donuts?

Also

I was sitting at my desk in School the other day, and i turned my neck awkwardly, and my neck clicked, i can do this with my fingers, and my back. What is this? I was told STOP IT!, because i would get arthritis. is this true

There is some evidence for this. But by and large, I would say arthritis is of a different cause. It is an autoimmune disease where the body turns against itself.

The last one you need to figure out yourself. Personally there are too many -ist's for me.

[elegantlywasted]

yah, i can crack pretty much everything... and it feels gooooooood [] but if it could lead to arthritis, why are there chiropractors(sp?)?

[SquarishTriangle]

The pressure that is exerted on us all the time...we're simply evolved to be able to withstand that (eg. we don't feel the forces of air particles colliding into our bodies at hundreds of kilometres/hour.) If those pressures were so great that life were not possible, we would not have come into existence in the first place...rather than being here now and suddenly dying.

The knuckle cracking is due to a build up of (synovial) fluid between your joints, I believe, which is released when you crack them.

[MayoFlyFarmer]

the answer to your question about pressure has partially do do with Triangle's explanation that we've evolved to withstand the pressure of our atmosphere.  chances are, if there is life on other planets of different sizes and atmospheric pressures, they would be evolved poorly to survive in our environment and visa-versa.  this is even true for some deep-water sea-life.
it also has to do with surface area and distribution of force.  the force exerted on your body by the atmosphere is spread evenly across the surface of your entire body.  think about if you put a knife up to your abdomen and exerted enough pressure that it pierced your tissues.  now imagine putting a brick up to your abdomen and exerting the same amount of  pressure on the bvrick.  you'd get a very different result.  that is because all of the pressure is concentrated in the tip of the knife versus across the entire surface of the brick.