Trinity College experiment succeeds after 69 years • Hacker News Board

Re: Trinity College experiment succeeds after 69 years

#71

Post by samatman » Thu, Jul 18, 2013, 5:20 PM UTC

samatman wrote: post #68

robomartin wrote: post #36

The first thought that popped into my punny little brain was: Why didn't they use a centrifuge to accelerate results? The one variable that could be controlled is the gravitational force on the substance. If we were on the moon the experiment, as designed, would take far longer to produce a drop. By using a centrifuge they could have easily simulated significantly greater gravitational forces and arrived at a result…

Chemist here. We use centrifuging to separate components of a suspension by weight. Pitch is a suspension. The heavy stuff would drop to the outside, the viscosity would be affected, no experiment.

Indeed, it occurs to me that one reason to keep watching the experiment is to see whether heavy pitch migrated to the bottom. If so, the rate should speed up in a few hundred years, assuming the hermetic seal is good and nothing is volatilizing off the top.

This is unlikely, however. Many suspensions have a critical pressure below which they simply will not settle. Homogenized milk, for a familiar example.

Re: Trinity College experiment succeeds after 69 years

#72

Post by carlsednaoui » Thu, Jul 18, 2013, 6:01 PM UTC

Heard about this the Pitch Drop Experiment on Radiolab couple weeks ago. Very interesting episode: http://www.radiolab.org/2013/feb/05/never-quite-now/

"...the Pitch Drop Experiment is so slow, you can watch it for hours (check out the live cam) and not detect the slightest movement. But that doesn't mean nothing's happening. Professor John Mainstone tells us about his desperate attempts to catch the flashes of action hiding inside this decades-long experiment."

Re: Trinity College experiment succeeds after 69 years

#73

Post by kriro » Thu, Jul 18, 2013, 6:04 PM UTC

RobAley wrote: post #54

elmuchoprez wrote: post #52

"Over several decades a number of drips did form in the funnel and fall into the jar, giving credence to the hypothesis that pitch is indeed viscous." It sounds like the experiment, as designed, reached a conclusion in far less time than 69 years. It just took 69 years for someone to think about video taping it.

Nope, assuming they designed it for scientific rigour. Without observation, it would be impossible to say, for instance, that some external force (vibration, wind, mischievous students) hadn't caused the drip to form or fall/break off. The experiment didn't reach a firm conclusion (to some level of certainty) without observation.

What if it's quantum-dripping and only dripped because of the camera :P

Re: Trinity College experiment succeeds after 69 years

#74

Post by aarondf » Thu, Jul 18, 2013, 6:15 PM UTC

That pitch was a little thick and quite slow. 6/10.

Re: Trinity College experiment succeeds after 69 years

#75

Post by robomartin » Thu, Jul 18, 2013, 6:20 PM UTC

samatman wrote: post #68

robomartin wrote: post #36

The first thought that popped into my punny little brain was: Why didn't they use a centrifuge to accelerate results? The one variable that could be controlled is the gravitational force on the substance. If we were on the moon the experiment, as designed, would take far longer to produce a drop. By using a centrifuge they could have easily simulated significantly greater gravitational forces and arrived at a result…

Chemist here. We use centrifuging to separate components of a suspension by weight. Pitch is a suspension. The heavy stuff would drop to the outside, the viscosity would be affected, no experiment.

> Chemist here. We use centrifuging to separate components of a suspension by weight. Pitch is a suspension.

The last bit is puzzling: Are all suspensions fluids? And all fluids are viscous (even non-newtonian)?

If so, why do we need an experiment to prove that pitch --a suspension-- is a fluid and is viscous?

On the point of using a centrifuge. Is there something particularly special about gravity on earth that does not affect pitch? In other words, if we exposed pitch to 0.1x, 1x, 10x, 100x and 1000x g, at what point would the fundamental characteristics of the material invalidate the experiment. Are fluids and their viscosity only defined on earth (ignoring thermal and other non-gravitational effects)? Perhaps pitch is a viscous fluid on earth but a solid on the moon, where gravity is 1/6 of ours?

Is this experiment only valid at 9.8 m/s^2 then? What's the tolerance based on the substance under test?

Re: Trinity College experiment succeeds after 69 years

#76

Post by comrade_ogilvy » Thu, Jul 18, 2013, 6:32 PM UTC

jkn wrote: post #20

While I'm fond of this type of down-to-earth experiments, I'm curious about the scientific value of waiting for decades to observe the drop falling due to Earth's gravity, versus placing the apparatus in a centrifuge, which I imagine would dramatically accelerate the process. Maybe the higher forces would affect the way the drop is formed, in a way that was deemed undesirable?

I would argue that confirmation of the shape in 1G has some actual value.

Sometimes "silly" experiments can have value. I chatted with a physic prof once who said the very first experiment he did after gaining tenure was to investigate the isotropy of the universe in particle accelerator experiments -- in other words, do the laws of physic work the same way when the accelerator is pointed one direction, relative to distant stars, as any other.

Obviously, the likely result would be nada.

However, if he found something, it would be two possible things: (1) He was going to earn an instant Noble prize, or (2) There was a potential subtle systematic design error particle physicists had overlooked -- knowing how to look for this error and/or correct for it could have value.

#2 was more likely. But why not?

Re: Trinity College experiment succeeds after 69 years

#77

Post by robomartin » Thu, Jul 18, 2013, 6:32 PM UTC

jerf wrote: post #70

robomartin wrote: post #57

Earlier quoted context omitted.

> At a million g's, I'm a liquid Not really. You'll disintegrate in strange ways based on the relative density of your constituent parts. : Another thought is that if you laid on a bed for 13 years (the time it took for a drop of pitch to form) without moving --ignoring tissue decay and other factors-- you'd probably "flow" just as you might in a high gravity environment. Gravity, like rust, never sleeps. Yet, unless…

I was admittedly being glib; obviously bone has different characteristics than fat. But characteristics can definitely unhappily change and I'd want an expert involved too.

Well, it looks like we have at least one Chemist pitching in (no pun intended). Time to learn a thing or two. Chemistry is one of those things I wish I had devote more time to in school. Lot's of physics and math but never dove deep into chemistry beyond what was absolutely required.

Re: Trinity College experiment succeeds after 69 years

#78

Post by dokem » Thu, Jul 18, 2013, 6:52 PM UTC

why did the pitch have to drip? Isn't the fact that a drip was forming proof that the pitch was flowing?

Re: Trinity College experiment succeeds after 69 years

#79

Post by kfury » Thu, Jul 18, 2013, 6:58 PM UTC

People have waited through so many failed attempts to record the drop that nobody wants to mention that they didn't 'really' record an unassisted drop. The bead is still connected when it hits bottom, and the tail doesn't break until they raised up the suspended platform.

Check the video and notice that the suspended vessel jumps about 2 inches higher just after the drop.

It's a good recording, but I'm looking forward to a better one in 2026.

Re: Trinity College experiment succeeds after 69 years

#80

Post by freehunter » Thu, Jul 18, 2013, 7:03 PM UTC

berberous wrote: post #23

dalore wrote: post #6

Earlier quoted context omitted.

How are they different? Both the article and the wikipedia link you gave mention they are similar experiments. It seems they are the same experiment to me.

Same experiment, but I for one was interested to know it was not the Queensland one, because that one has a great Radiolab episode about all the times they missed the drop (webcams failing, etc.). Their pitch is due to drop soon too, so it's sort of sad someone else beat them to finally filming it.

Sounds like the pitch may actually contain the Higgs Boson, and it is going back in time and creating events designed to make the monitoring fail. The failing webcam was the proverbial bird that dropped bread into the coolant pipe.