There are two types of spheres: pure gold spheres and pure silver spheres. The sterling silver sphere is packed to the core, while the sterling gold sphere has a space in the center. Both have the same radius and the same mass. The surfaces are coated with paint that cannot be seen through. Identify which sphere is made of pure gold, but do not cut or otherwise destructively examine it.

I was shocked to observe that some people would answer this question with ā€œArchimedesā€™ principleā€ or something like that.

What he is trying to say is that Archimedes was told to find out whether the crown was pure gold or mixed gold without breaking it, so he prepared pure gold of the same mass as the crown, hung it on a balance, put it in water, and discovered that it was not pure gold because it tilted.

Why donā€™t they realize that it canā€™t be done that way?


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