Science class!?!?!?

Question

Today in science class we learned that if you put a wet cloth soked in viniger on your arm or sliced a potatoe and put it on your arm then it would weaken the bone? Is that true? That was the fun fact for the day and a little gross. If this is true then WHY? and would your bone stay weak forever? If any one knows the scientific reason why then please tell why.

Answer 1

Someone has misinterpreted something here...

If you take a chicken bone and submerge it in vinegar for several days or a week, it will leech out the minerals that give it strength and you can bend it as though it was made of rubber.

That has been somehow extrapolated to the wet rag on the arm (which won't work unless you remove the skin and underlying tissue first, in which case the weakening of the bone will be a secondary concern).

The potato thing sounds like a complete fabrication.

Ask your source of information for their source of information -- where is this claim backed up (be wary if they cite something from the internet as a source).

To me this sounds like something someone once heard and accepted as unsubstantiated "fact".

Answer 2

It's true, but the bone won't stay weak forever; just for a few days until the natural process of renewal built it back up again.

The vinegar would weaken the bone because vinegar is a weak acid. The vinegar would soak through the skin into the bloodstream and thence to the bone, where the acid would leach some of the calcium out. I'm not sure about the potato; maybe a base (opposite of acid; high pH as opposed to low) would have the same effect.

Answer 3

Assuming it is true...it may not be...the vinegar would eventually pass through the skin (doing significant possible acid burns) and enter the blood stream.

Hmm...taking that into account, it couldn't happen...enough acid to weaken the bone of your arm would cause major toxic effects to your bloodstream, including possibly fatal levels of anaemia, and acid burns/irritation.

I don't understand how the slice of potato (note, that unlike a certain Vice President, I can spell that vegetable's name) could do what your teacher claimed either... Although the rot it would eventually turn into could do some serious harm...

Please note that placing a bone into pure vinegar will still take days or longer to have an easily measurable loss of calcium. That is dead bone. Living bone heals itself. In any case, bone also completely replaces itself every 7 years, so with a proper diet, in 7 years, any damage that might have occurred would have been "erased."

Answer 4

That doesn't sound true.

Although raising pH in the blood triggers the body to draw calcium out of the bones, the action would not be localized. All of your bones would weaken, not just the arm with vinegar on it. Your body releases hormones that trigger the bones to lose minerals--so how would the hormones know to go to the arm? They wouldn't....

Not to mention that if the vinegar did make it into your blood stream it would be circulated throughout your body and not just sent to your bone....