Mystery of the hollow World Cup?

With the World Cup upon us I thought we should do some sort of themed video for The Periodic Table of Videos.

A bit of internet research quickly showed the trophy is made of solid gold (18 carat) and includes a precious mineral called malachite.

So I asked the The Professor for some insights about gold and malachite.

But something else occurred to me...

I've been told that gold is deceptively heavy (because of its density) and many people cannot lift a modest-sized sample.

So why isn't the hefty World Cup (about 36cm tall) incredibly heavy?

Players never struggle to lift it and according to Fifa it weighs just over 6kg.

So The Professor cracked out his ruler and beat-up old calculator for a few calculations.

Sure enough, he deduced there's no way the World Cup can be solid gold all the way through - otherwise it'd weigh more like 70 to 80kg.

So what's inside?

Is it hollow? Is there another metal or substance Fifa don't include in the tech specs?

Whatever the case, it made a fun video.



As a postscript, within hours of the video being posted someone had gone onto Wikipedia and re-written the trophy's description to include the following:

"It has been asserted that the trophy is likely to be hollow due to the high density of gold and that, if solid, it would weigh in the region of 70-80 kg."

They've even included our video as the reference!

I've got to admit our figures were a bit rough and based on the published measurements and pictures supplied by Fifa.

And I must point out no-one has ever said the World Cup is NOT hollow (though the words "solid gold" seem a shade misleading!)

But I'm glad it has got people talking about science and looking at that famous trophy in a new way.

PS: I've subsequently read an interview with the sculptor revealing it was created using the lost wax method. The Professor had already suggested this was likely off camera!