Thursday, 29 August 2013

Bad science ? Or just bad mathematics ? Or just me ?

From this BBC News article: -

A team of researchers claims to have created the world's fastest spinning man-made object.

They were able to levitate and spin a microscopic sphere at speeds of up to 600 million revolutions per minute.

This spin speed is half a million times faster than a domestic washing machine and more than a thousand times faster than a dental drill.

For some reason, this piqued my interest.

The way that I read the two highlighted phrases is this: -

1) The researchers have an object that can spin at up to 600 million RPM ( 600,000,000 RPM )
2) That is 0.5 million ( 500,000 ) RPM faster than a domestic washing machine
3) Ergo, domestic washing machines spin at 599.5 million RPM ( 599,500,000 RPM )

According to another reputable ( in my personal opinion ) source, Which?

Many washing machines boast a high 1400 revolutions per minute (rpm), 1600rpm or even 1800rpm spin speed rather than the more common 1200rpm, which helps save time on the line or energy use in the tumble dryer by removing more water. However you'll usually pay extra for this feature, and 1200rpm is generally adequate for most loads.

So the BBC are comparing this lab experiment with a washing machine … that can spin at 599.5 million RPM.

Can someone please explain the error in my working ? 'Cos I am

1 comment:

Dave Hay said...

And, as if by magic, one of my Twitter buddies, Mr Andrew Frayling, kindly pointed out the error in my thinking: -

"it’s you :-) 1200 rpm washing machine * 500,000 = 600,000,000"

to which I responded: -

"Ah, of course, I was (stupidly) reading it as "half a million RPMs faster than a domestic washing machine" - Can you say "Doh" ?"