Saturday 20 April 2019

All eyes on 86-year experiment as pitch comes dropping slow

Robin McKie

In terms of output, Queensland University's pitch drop study – the world's oldest laboratory experiment – has been stunningly low. Only eight drops have emerged from the lump of pitch installed in the university's physics building foyer in 1927.

But excitement is now rising over the experiment, which was set up to calculate the viscosity of the world's stickiest substance, pitch, which has been found to be at least 230 billion times more viscous than water.

According to Professor John Mainstone, who has run the experiment since the 1960s, a ninth drop looks set to emerge from the pitch block in the very near future.

"No one has seen a drop emerge, so it is getting quite nervy round here," said Prof Mainstone. "The other eight drops happened while people had their backs turned. For the last drop, in 2000, we had a webcam trained on the experiment, but it broke down . . . in 1988, when the previous drop was about to emerge, I popped out for a coffee and missed it."

The fact that pitch – which is so brittle it can be smashed with a hammer – behaves like a fluid is the most surprising aspect of the experiment, added Prof Mainstone. "This time we have got several cameras trained on the pitch sample to make sure we get a sight of it dropping. It will take only about one-tenth of a second. On the other hand, I am 78, and the next drop is unlikely to fall for at least another 10 years, so this might be my last chance to see it happen."

Prof Mainstone will share the experience with people who watch the unmoving lump of pitch on computers around the world – in the hope they will catch the moment when the experiment actually produces a result.

© Observer

Irish Independent

Today's news headlines, directly to your inbox every morning.

Editors Choice

Also in World News