Weekly Roundup 93


Weekly Roundup 88

Sometimes it can seem like physics is overcomplicating things: for instance the idea of “sucking” water up a straw being replaced with atmospheric pressure pushing it up the straw. In a similar vein, why does water fall out of an upside down cup? I will not deny that when I was asked my first response was the slightly unsure “because of gravity, right?” The person talking to me at the time pointed out that if it is really the force of gravity acting on the water’s mass, why haven’t I thought about atmospheric pressure. It takes 10.2 metres of water to match pressure with however many kilometres of air we have above us and clearly there is not 10.2 metres of water in a regular cup, so logically the pressure from the water when the cup is turned over should be overwhelmed by the pressure of air. The ultimate solution is a matter of equilibrium.

Image result for stable and unstable equilibria
Thank you to The Science of Doom for this image

I find it slightly comedic that the stable equilibrium kind of looks like a cup the right way up and the unstable looks like one upside down. When a wave is created in water it is gravity which pulls it down, and water tension and pressure which pushes it back up. Luckily, on the surface of a lake, these forces act in opposite directions and so a nice stable wave is created. In an upside down cup, both forces act in the same direction and so any wave or slight ripple is incredibly unstable and is destined to fall.

An interesting idea to wrap your head around, until tomorrow, goodnight.

Weekly Roundup 87

One of the most interesting questions I have been asked was on the concept of eternity (in a divergent point “eternity” is a poorly used word with people using it to both mean “constant” and “forever” even when they themselves do not agree with the situation they use it in). Time appears to have had a definite start point, that being the beginning of the Universe. Before the universe there was no time and yet despite the finite time of the past it seems like there is an infinite possible future. This thought ultimately comes back to the question of what is time? One of the most common definitions is that the arrow of time always moves in the direction of increasing total entropy, which is true. Entropy must always increase. I have also heard the interesting definition that the arrow of time must always move so that radiation travels in outgoing spheres. Spheres of radiation waves that travel to a point are impossible and so it can be seen that time and growing spherical waves are connected (although perhaps just by the entropy definition). Is it then possible that once there is no more work left to do, and entropy has reached a maximum, time no longer has any meaning. For a start it won’t have any meaning because there will no being left to experience it but also because there will be no more change. The universe will have finally become static, frozen and unmoving. In other words a universe devoid of time.

I suppose we have to hope that dark energy really does exist and that there is some force working to prevent such an end that we can harness but this really beyond the concern of anyone currently living. Until tomorrow, goodnight.

Weekly Roundup 86

Trust is a very important but also a very interesting thing. Trustworthiness is not really a quality that an individual possesses but one that is projected from everyone around them. It’s not possible to be trustworthy if there is nobody there to trust you. Luckily, in the UK at least, trust in scientists seems to be quite high, according to this report. It seems that interest, trust and engagement with science are staying high although there are complaints about scientists and engineers being secretive with their work. One of the interesting things mentioned was the fact that people have more faith with scientists who work for universities than they do those who work for companies. Overall there seemed to be confusion about both the peer review process which I talked about last week but also the funding process for science. As a result I am considering writing detailed pages about both of these topics which may be done over the coming weeks if I can get round to it. Until then I’ll just take solace in the fact that science seems to be a respected source of information in a world where some people are claiming the death of truth is upon us.

Until tomorrow, goodnight.

Weekly Roundup 85

I was considering writing this weekly roundup on the importance of peer reviewed publication. I could have written many paragraphs on the essential nature of experts evaluating papers, but luckily I don’t have to. A man named Peter Hadfield who owns the youtube channel potholer54, has recently published this video (slightly inappropriate for children) which I was lucky enough to find. In it, he articulates in a much more proficient way than I could the difference of quality between scientific journals and the importance of reputation in the review process. All I really need to add is my own little analogy. In a game of sudoku there may come a time when you realise that you have somehow managed to place two 9s in the same row. The problem is not just as simple as erasing both numbers and rederiving your logic as it is impossible to know how many other numbers in many other places were put there based on a faulty 9. If one ridiculous paper manages to sneak into a respected journal then it will be trusted by the nature of it just being there and once its been used as a supporting citation in another set of papers the problem is already out of control.

Hopefully the importance of scientific purity is now quite a bit clearer. Until tomorrow, goodnight.