You are a researcher for a golf club manufacturer. You are given two identical looking cubes of a metal alloy. You are informed that they are made of the exact same material, but one is a crystalline, while the other is amorphous. It is your job to determine which one is amorphous because this one is more stress-resistant and is useful in reinforcing golf clubs. Which of the following is the best way to determine which is which?

Question

A.  Determine the density of each cube. The more dense one is the amorphous solid.
 
B.  Determine the density of each cube. The less dense cube is the amorphous solid.
 
C.  Melt both cubes and look for a broader range of melting temperatures. The one that melts over a broader range of temperatures is the amorphous solid.
 
D.  Melt both cubes and measure the range of melting temperatures. The one that melts over a narrower range of temperatures is the amorphous solid.

This is what it said when I had answered: "C"

Feedback:

While melting the cubes would help you determine which is which, it would destroy the atomic geometry, so the differences would disappear when you cooled them down to the solid form again.

Should the answer be "B" then??

K · Accepted Answer

The answer was B

DrBob222 · Answer

Personally I think this is a flawed question. It did NOT ask to determine which was which by a process in with the state was not modified; it asked to determine which was which and the melting point (broad for amorphous and sharper for crystalline) works very well. The fact that melting the amorphous solid allows it to crystallize when cooled is beside the point. And you wouldn't need the entire cube to determine the melting ont this way; only a very small amount would be necessary. So the question really has two answers; perhaps I should say the answers are flawed and the question is ok.

K · Answer

I will send a msg to the site & see what I receive back. I figure that D should have been correct initially, but I picked C instead by accident...it came up with the feedback stmt & I got more confused.

Anonymous · Answer

The answer is B.