Will It Grow Or Shrink?

Suppose we had a metal disk of the same material at the same temperature which perfectly filled in the hole. If we then heat the material, I think no one would argue that the disk would expand and keep the hole filled. Afterward, we remove the now expanded disk and see that the hole must also have expanded.

Repost from : Physics Stack Exchange

Instead of a circular hole, let's think of a square hole. You can get a square hole two ways, you can cut it out of a complete sheet, or you can get one by cutting a sheet into 9 little squares and throwing away the center one. Since the 8 outer squares all get bigger when heat it, the inner square (the hole) also has to get bigger:

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Same thing happens with a round hole.

This is confusing to people because the primary experience they have with stuff getting larger when heated is by cooking. If you leave a hole in the middle of a cookie and cook it, yes, the cookie gets bigger and the hole gets smaller. But the reason for this is that the cookie isn't so solid. It's more like a liquid, it's deforming. And as Ilmari Karonen points out, the cookie sheet isn't expanding much so there are frictional forces at work.

Credit answer : Carl Brannen

Carl Brannen

simple logic, the metal plate will expand as a whole system hence the hole grows too

It will grow because in thermal expansion, object expand just like as a photograph (to say,).

The object expands in all directions on heating as if we are magnifying through a magnifying glass. So, the hole must also expand.

If the hole hadn't expanded, then that would have meant that some extra material had been added as the net mass would have increased then. But here, the mass is constant.

Instead of a circular hole, let's think of a square hole. You can get a square hole two ways, you can cut it out of a complete sheet, or you can get one by cutting a sheet into 9 little squares and throwing away the center one. Since the 8 outer squares all get bigger when heat it, the inner square (the hole) also has to get bigger. The same thing happens with a circular hole.

think it as a ring, when you used to heat the ring its area will increase no doubt, so as in this problem the area of ring should increase owing to increase in area of hole and increase in radius and for them who think that area should decrease i am having an explanation think of the atoms of the material when they are heated the atoms or molecules tend go away from each other as their K.E increases so how would they come close to each other.......

Its obviously going to expand as that is the only possible scenario.coz its a hole.not metal.wel the metal surrounding the hole have 2 ways in which it can proceed but inwards is not plausible coz its constriction of the perimeter particles of the hole and we are talking about heat and expansion here. So the metal takes the other direction coz now it is free to expand limitlessly..of course practically it has a limit.lol.

The metal expands due to heating and hence as a result the hole becomes bigger you can try it out yourself ...

molecular/atomic space will increase after getting heat. As a result the circumference of the hole will increase as the molecules/atom is same number that are used to build the circumference.

METALS EXPAND UNIFORMLY PEOPLE SO EVERY PART EXPANDS... SO THE HOLE EXPANDS TOO...

Because heat expand metal

It's easy. Just like the base of thermal expansion.

in thermal expansion,everything grows !!

every material grows if heated

the hole will expand too, just like, it was a metal disc in place of it.

The plate will be expand in 3D , then the hole will grow

it will expand on heating

metal expands on heating