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Makes watching paint dry seem dizzying

Have you heard of the Pitch Drop Experiment? It’s the longest-running ongoing lab experiment EVER.

Pitch, like what they put on the hulls of ships, seems like a solid at room temperature. Even brittle. But it ain’t. It’s a very, very viscous liquid, 100 billion times more viscous than water.

To demonstrate this, Thomas Parnell, University of Queensland’s first Professor of Physics, made a thing. In 1927, he heated some pitch and poured it into a sealed glass funnel. After three years – I guess he wanted to make very, very sure it was cool – he snipped the end of the funnel off and waited. And waited. And waited.

It has taken eight to thirteen years for each drop to fall. It’s a demonstration, not a proper experiment, so it isn’t in an environmentally-controlled environment. Meaning, it makes faster progress when it’s hot out.

Nobody has ever seen a drop fall. Per the link above: “In the 86 years that the pitch has been dripping, various glitches have prevented anyone from seeing a drop fall.” I don’t know what ‘glitches’ happen outside computers, I merely repeat what I have read.

But you might see it! It has a webcam! The ninth drip fell in 2014, so only another two to eleven years to go on Tenth Watch.

I know what I’m doing this weekend. Have a good one!


Comment from p2
Time: March 19, 2021, 8:51 pm

Do they keep track by date? Maybe a Drip Pool, akin to the Deadpool is in order? Guess the date and win Certificate of Drip Dropping on fairy shit paper!

Comment from durnedyankee
Time: March 19, 2021, 10:09 pm

Glass, it seems, is also a very slowly moving super cooled liquid.

You’re more likely to notice that over yonder across the sea where you have old glass in buildings. It explains why old windows are thicker at the bottom, it’s slowly slumping.

Comment from durnedyankee
Time: March 19, 2021, 11:09 pm

@BJM – CHEESECAKE! In a pressure cooker! Who knew!

Comment from weasel again
Time: March 20, 2021, 10:05 am

Uncle B and I had a discussion about glass last night, durned. I have always heard it your way – that glass is very slightly liquid. I have since read that it is not a very viscous liquid and the reason glass panes are thicker at the bottom is that they were made thicker at one end and they were installed with that bit at the bottom. I am not a physicist so I could really say.

Comment from durnedyankee
Time: March 20, 2021, 4:28 pm

But I checked it first! Honest. Because I too have heard it both ways.

and it was on the internet, so, ya know it has to be true!

And typing “glass liquid myth reveals”
From Scientific American, which I once trusted before the Great Gerbil Warming ‘science’ and the “this piece of cotton cloth is a mask and will stop virus droplets even though it won’t stop smoke particles!” science.

So your mileage with the Science in Scientific American may now vary – yet


Comment from ExpressoBold
Time: March 21, 2021, 8:53 pm

All the way back in 2013… with links!

“The ‘glass is a liquid’ myth has finally been destroyed”


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