Expand your Mind

Good job...I'll make grillers of you yet. yes, the way to do it was to cook burger 1, side 1 and burger 2, side 1 for five minutes, then flip burger 1 and put on burger 3, side 1, for five minutes (burger 1 is now done), then do burgers 2 and 3, side 2, for five minutes.

OK, easy one today, that a surprising number of people get wrong:

It is a well-known fact that metal expands under heat. If you held a solid piece of iron, that is in the shape of a doughnut, over extreme heat, will the hole in the centre of the iron doughnut grow larger, smaller, or will it remain the same?