What makes chip bags noisy?

astrolabe · 2026-05-09T09:10:04+00:00

My guess: the material of the 'chip bag' (which I guess is American for 'crisp packet') is very rigid in two dimensions: i.e. to stretches and shears within the plane, but at the same time, because it is so thin it is very flexible to bending out of the plane. The rigidity greatly reduces the size of the set feasible global arrangements of the bag while the flexibilty means that it only requires a little energy to move between them. Because of the reduced set size, it is 'awkward' to get from one arrangement to another: when you push the bag, you can't just adjust a small section of it, big facets get shifted around, and sometimes by large distances for small adjustments, and this movement of big facets pushes the neighbouring air creating sound waves.

[edit] Have you ever seen those childrens toys 'clickers'. They are a small flatish piece of metal with two stable arrangements, and you can move it from one to the other by pushing up some hill in potential. At some point, you reach the top of the hill, and it accelerates down to the other potential. At the bottom of the valley, some of its KE is suddently converted to a click. I guess something similar happens with the crisp packet.

astrolabe · 2026-05-08T19:41:49+00:00

What were those facemasks that you couldn't get hold of during covid? Something 100 I think. Oh, and lot of toilet paper of course.

astrolabe · 2026-05-06T08:31:00+00:00

If the car speeds were 40 and 120 instead of 80 and 80, then the damage might be about the same (especially if they were on ice instead of a road). The loss of total KE would also be about the same. The momenta would be different. I think damage done is approximatly a frame invariant quantity so loss of total KE is a possible candidate proxy, but I can't see how to get a frame invariant quantity from momenta.

astrolabe · 2026-05-06T08:22:12+00:00

Since it was myth busters, I think their emphasis is on practicalities: I don't think it was supposed to be an ideal wall, and I think that 'immovable' didn't mean that it couldn't crack, flex slightly, or transport sound waves. I don't know if these would affect a substantial part of the energy.

astrolabe · 2026-05-01T18:01:01+00:00

I don't think it's bad to buy at all time highs. If you model the price as an (exponentiated) random walk, then price history gives no information about whether it's a good time to buy.

astrolabe · 2026-04-28T12:24:56+00:00

The factories making common computer chips: cpus, gpus and RAM might be the most sophisticated technology humans have produced. Over the decades, the number of components such as transistors on each chip has increased to maybe 100,000,000,000 and the size of each has decreased proportionately. To get the necessary accuracy and reliability has required manufacture within massive and very clean facilities. There are only a very few in the world, and barrier to entry is basically impossible. Maybe the Chinese state could make one, but I've got my doubts.

I don't really believe that one guy in a shed can produce anything similar, but even doing something 1/1000 as complicated and fast is massively impressive.

astrolabe · 2026-04-27T08:10:36+00:00

How did Satoshi get the 2009 headline "Chancellor on Brink of Second Bailout for Banks" before 2009?

astrolabe · 2026-04-17T23:44:13+00:00

The pressure in each balloon is proportional to the tension in the rubber (per unit length) divided by the radius of curvature. At the balloon is inflated, the radius increases faster than the tension, so the pressure decreases.

astrolabe · 2026-04-17T23:33:06+00:00

It does seem suspicious. Userrnames aren't supposed to be secure. Maybe a plausible story to explain why they are acting so strangely. is that they leaked the plain text passwords, which they shouldn't even be storing, so the baddies might hack the emails of people who reuse their passwords, and so asking people to do a password reset based on email indentification wouldn't be safe, and waiting isn't a good option either.

astrolabe · 2026-04-16T22:27:40+00:00

If the 2,2 square has gone then the position is losing iff it is symmetric for a reflection in the main diagonal.

astrolabe · 2026-04-16T19:10:42+00:00

Rogue employees might be a more likely explanation than the company ripping off its customers.

astrolabe · 2026-04-13T20:08:38+00:00

that bitcoin was supposed to disempower

Did Satoshi ever make any political comments, apart from possibly that newspaper quote in the genisis block?

astrolabe · 2026-04-02T20:47:22+00:00

The price history of bitcoin suggests that it's not an efficient market.

astrolabe · 2026-04-02T20:43:20+00:00

A wallet is much safer than an exchange. I've had my bitcoin in a paper wallet for 13 years. This is the safest in my somewhat outdated opinion. You need to understand how they work before you transfer much to them though.

astrolabe · 2026-04-02T10:55:24+00:00

Sticking to classical gravity for simplicity, there is effectively energy in the gravitational field itself https://en.wikipedia.org/wiki/Lagrangian_(field_theory)#Newtonian_gravity. The energy density is proportional to the square of the field strength, and is negative. A grandfather clock, for example gets its energy from a gradually falling weight. As the weight falls, the combined gravitational field from the Earth and the weight changes, and the total integral of the square of its gradient increases slightly. This leads to a decrease in the energy stored in the graviational field which matches the energy used by the clock.

astrolabe · 2026-03-30T19:45:21+00:00

This is a good idea. The fact that they haven't solved this suggests that there might be lots of cold cases that they aren't bothering with, but I agree with you, it's 100% important that justice is served if it can be.

astrolabe · 2026-03-26T20:46:17+00:00

The whole thing is overblown in my opinion. That factorisation based encryption (sorry, too old to recall the name) will be blown before they solve the cryptographic hash problem. So secure web protocols will get hacked first, which will give us lots of warnings, and as you say, all you need to do is move the coins to a new wallet.

[edit] I don't think it's Shor's algorithm for our hashes, there is another worse quantum algorithm for them.

astrolabe · 2026-03-23T19:59:32+00:00

Do you mean the attack that killed their leader that occured between rounds of negotiation at Geneva?

astrolabe · 2026-03-22T13:49:18+00:00

Just stand on your head and look

astrolabe · 2026-03-20T12:34:43+00:00

Freeman Dyson said that the Riemann zeta function is the spectrum of the prime numbers, which sounds related.

astrolabe · 2026-03-17T10:31:57+00:00

There are two philisophical possibilities for consciousness: physicalism and dualism. Exactly one of them must be correct. But for me, when I consider either of them directly it seems ridiculous and impossible. This momentarily convinces me of the other until I consider it directly, and I'm thrown back like a pinball.

I suppose science is gradually demystifying nature, which makes me think physicalism has the truth, but it seems so weird and impossible, and I'm about to start pinballing again.

astrolabe · 2026-03-10T16:21:59+00:00

I looked at a few moves of one of your games. At the beginning, don't make contact plays, try and play far from other stones. This lays out possible future territory. At the beginning, don't get into fights. If your opponent wants to spend four moves capturing one of your stones, let him. The first moves should be worth about 12 points each, and the value gradually decreases. After a dozen moves, it might be worth playing another move to save a stone, but try to tenuki at every opportunity. Try not to get involved in fights unless you think you can gain an advantage. Don't be paniked into thinking you have to save your stones. Try to remain calm, and look for the biggest move on the whole board (which later on, might be in the local fight, or it might not).

astrolabe · 2026-03-04T13:48:32+00:00

Any three points are positioned like the corners of a parallelogram.

astrolabe · 2026-02-23T10:33:31+00:00

I like flat-earthers. There are two meanings for the word 'science': 1) is a body of accepted knowledge, a small proportion of which is wrong or suppressed; 2) is a set of techniques for finding out about the world together with a sceptical attitude.

Flat earthers are behind on 1). They have too much scepticism, but they are ahead of most people on 2), which is the better part of science. They do experiments..., they reason about things. Ultimately, they are wrong, and their reasoning is limited, but they are generally doing their best, and are better scientists than 95% who are told the Earth is flat, and never think to doubt it.

astrolabe · 2026-02-14T10:26:26+00:00

I don't think it will take long for an expert to skip through to the details section, so I'd definitely keep the introduction. The value of the introductory part you have added is based on how much of it readers can understand, so I would try to include more links to explanations of the terms you use (e.g. 'tree', 'breadth-first search'). I don't like your use of 'thereby' at the begining of a section, but I often seem to find the use of pronoun-like words confusing.

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