Things that have made me sit up:
Japan has a population of 130 million. It is the largest (by population) non-western developed nation. Edit: It is also the second-largest developed nation in the world.
Areas of countries, especially African nations. For example, Mali is larger than France, Germany and Italy combined.
My idea of real-world violence changed dramatically after reading Randall Collins. In short, it is far rarer than you think, everybody involved is extremely fearful of it, nobody is very good at it and it really is nothing like the movies. For example, they are usually very short: O.K. Corral was 30 seconds long.
Chile is in the same time zone as the East Coast of the US.
Japan has a population of 130 million. It is the largest (by population) non-western developed nation. Edit: It is also the second-largest developed nation in the world.
In a similar vein, Canada has a population of barely 35 million -- that's 9 times smaller than the US population -- while being the second largest country (by territory) in the world. It is almost as big as the whole continent of Europe, and yet there are 8 European countries (or 7 if you don't count Russia) with higher population counts. Most Canadians live within 100 km from the border with the US. The rest of the country is basically empty.
- Chile is in the same time zone as the East Coast of the US.
I think more people get caught off-guard by the fact that Chile is in the opposite season of the US.
Those people must not like pomegranates nearly as much as I do. I spend several months of each year appreciating that Chile is in the opposite season.
Gene Wolfe's Book of the New Sun was full of many exotic things, but the fact that temperatures were hotter when the characters went north was still reliably weird for me.
Not OP, but I expected Japan to have about 40-50 million, about on par with California and South Korea. 130 million is huge.
The Tokyo metropolitan area alone has approximately the population of California. The population of Japan has pretty intense urban concentration.
Making it the largest Muslim country in the world.
(Before learning this fact, Indonesia wasn't even on my radar when discussing Islam. It's quite moderate, so it rarely makes the news.)
Here's one, though of a different sort. Five or ten years ago, I heard about an African film festival held in Africa. I immediately realized I'd been assuming things were much worse in Africa than they really were.
Since then, I've heard various pushbacks against the idea that Africa is a continent of disaster.
I immediately realized I'd been assuming things were much worse in Africa than they really were.
Presumably, things are different in different parts of Africa.
This is less a discrete fact and more a body of experience that influenced my view here, but I think it still falls under the topic. Part of me feels like this should be obvious to the average LWer, but on the other hand it seems to be a very common malfunction among adults.
When I was a kid, probably until sometime in High School, I thought that if I saw someone wearing, e.g.
... I would believe that this individual was probably actually dangerous. I would be frightened by the sight of them, and believe that there was a good chance that they would mug me.
Eventually I realized that these are merely the uniforms of various subcultures loosely enveloped by ethnic lines, and that seeing somebody wearing "thuggish" attire is very very weak Bayesian evidence that they are actually a thug, especially if you encounter them in a shopping mall or walking their dog at a park.
The most in...
For some (not all) of these cultural patterns, what happened was that the attire in question really was initially associated with thugs. In a rough neighborhood, you are either predator or prey. Even if you are not actually a thug yourself, it is safer to look like one, so that the actual predators mistake you for another predator rather than prey. It's like viceroy butterflies imitating monarchs, but without the actual evolution.
Also, the difference in crime rate might amount to something like "if you walk through the areas once a day, you'll be mugged on average once every ten years or once every thirty years."
There may be a difference between the rate at which a resident (who's probably at similar income to other residents in the area, and perceived as an insider) would be mugged, and the rate at which a visitor (seen as likely to be carrying more money, and perceived as a outsider, and the residents won't have to come face to face with them or their families again) would be mugged.
That said, as I noted in a previous comment, there are definitely cases where people are prone to designate a place as "dangerous" when it's not actually statistically more dangerous than where they already live. The fact that visiting these neighborhoods may be more dangerous per time spent than living in them doesn't make it likely that people who refuse to visit them are assessing risk realistically.
Looking at the relative calorie values of different foods radically changed my eating habits. Especially realising how high calorie 'boring' things like rice and bread were, vs. 'fun' things like bacon. Good example chart here.
It's worthwhile to pay people to do mundane things for you more often than you'd think. Most people underestimate the cognitive load these mundane tasks place on them in that they are surprised how happy they are with not doing them once they try it.
You can automate aspects of them. I have heard that people have had success using Amazon's 'subscriptions' where you set up a recurring order every X months for a particular foodstuff or household good, which certainly could help reduce time on grocery shopping.
This is already known to readers of XKCD, but I was blown away when it was pointed out that The Little Mermaid was released closer to the first moon landing than to the present day. It made me realize how much time has already passed in my life.
Atmospheric pressure, how strong it is (in absolute terms, ~15 psi/100 kN/sq m), and how little we notice. A rough demonstration:
You know those 15-lb (~7 kg) dumbbells? Ever lifted one? They're heavy. (No bragging, please.)
Now, place your hand on a table, palm up, and rest the dumbbell on your palm. "Ow!", right? That hurts! It feels like your hand is getting crushed! Get that thing off!
Well, you've only increased the pressure that's normally on your hand by about 5%, plus or minus.
This is very misleading. Most of the discomfort would be from the hard table against the back of your hand, and this would be because of local pressure on specific points.
Pressure causes problems when there's a big change in a relatively short time. Ears, for example, have a hard time with this, but you can equalize them by closing your nose and mouth and trying to blow out. Before I knew about this trick, I could never dive to the bottom of the pool. Now, no problem.
A more realistic example would be to bury your hand in a foot or two of fine sand. Does that sound uncomfortable?
In the sand example, it's also important that the pressure is acting from all sides (top, bottom, left, right) so there's no force acting to deform your hand.
We can handle a relatively large range of pressures, and there are other problems before you start causing mechanical damage from the actual pressure (lack of oxygen at low pressure, dissolved gas at high pressure).
edit: grammar
I don't agree with this.
Your thought experiment with the dumbbell is an incorrect way of thinking about ambient pressure. Ambient pressure pushes against an object from every direction. It does not work to deform or break, only compress from all sides.
Picture this: You have a hand-sized water balloon on a table. You place the two dumbbells on it; it breaks. You have another water balloon. You take this one, tie it to a dumbbell, and drop it into deep water. Do you expect it to break when descends to 3 feet (i.e. 10% increase in pressure)?
I would not expect it to break at all. When water and other non-gases are put under pressure, the bonds and repulsive forces within push back.
Don't quote me on this part, but I would guess that to break a bone with just ambient pressure, you'd have to raise the pressure to about the compressive strength of the bone, around 100 megapascals. For reference, standard atmospheric pressure is around 100 kilopascals.
edit: changed 3 meters to 3 feet, per prase's comment.
The suicide bombings in Israel drastically decreased after the construction of the wall to keep Palestinians out.
Also, it's dangerous to use Wikipedia articles that are "lists of X" to find the prevalence of X. You don't know how well the article is maintained; it could be that for some reason (perhaps as simple as what year the majority of the editing was done) one year's incidents are just represented in the list more.
The suicide bombings in Israel drastically decreased after the construction of the wall to keep Palestinians out.
That's one of those "uncomfortable but true" things that sometimes surfaces here (and threads get dedicated to explore): segregating walls do work.
Before looking up all of these facts, it would've been interesting to attempt to Fermi estimate them; that could've helped you uncover more stuff that's mistaken in your model of reality.
Isn't that like trying to estimate unknown unknowns? If one has already reached the point of thinking, 'wait how many major plane crashes have there been in the USA in the past decade, exactly? Why... I can't seem to think of any!'', one has already done most of the perspective changing.
If every car crash received headline coverage due to hundreds of people dying simultaneously horribly, followed by sporadic articles as the investigation of that car crash went on and profiles of people who died in the crash, then not being able to think of any recent car crashes probably means that there weren't any, not that the entire media industry collectively decided to stop covering them.
Of course it's more reliable to look them up, but the point of doing a Fermi estimate here is to figure out what else you might be mistaken about. For example, if you do a Fermi estimate about how much a rocket costs and it turns out to be really inaccurate, you might learn that that's because you have a really inaccurate picture of how much engineers get paid, or how many engineers it takes to build a rocket, or how much the materials for something like a rocket cost, or...
Anna and I actually did a Fermi estimate of the fuel for the Apollo 11 mission over dinner last week, and we were off by a factor of two. Some of the available inputs:
That's more a fact about the massive volatility of resource-extraction economies than anything else, really. That's how you get things like a projected GDP growth rate of +60% this year and -50% last year in Southern Sudan (those are not typos).
Besides, it's much easier to be "fast growing" when you start from a low base. That's why "fastest growing" almost always indicates hype when used to try to sell you something.
Declines in air passenger volume lead to substantial excess deaths from auto accidents, as consumers substitute driving for less dangerous air travel. The variables are pretty hard to isolate and the linked paper examines only one unusually dramatic case, but this effect could have far-reaching implications; for example, if the paper's accurate in citing a 5-8% decline in American air travel linked to stricter and less convenient passenger security screening, then these screening procedures may be actively counterproductive.
Think terrorist attack on Israel - did the phrase "suicide bombing" spring to mind?
Stuart, does "rocket" spring to mind? I wonder to what extent the rain of rockets on the southwest since 2006 (on and off, but with long periods of "on") registers on one's consciousness out there in the UK.
Rating agencies have historically actually been very good at predicting corporate defaults.
I have data on this but it is not public. However, I suspect there is public data available as well.
Not sure if this is political, but I understood why people in America were so obsessed with gay marriage much more when I realised that spouses get health care automatically. So people weren't really (or not exclusively) getting upset over a symbolic distinction but a practical one.
There's been a similarly large fuss over gay marriage in the UK, where 1) the NHS provides healthcare to everyone and 2) existing civil partnership legislation gave gay couples all the benefits of straight couples. So I don't think that practical issue is very important.
(Also, there are many far easier ways of getting health insurance than by upsetting arguably the most important institution in the history of the world!)
Your observation on this subject disagrees with mine. I'd say there was significantly less fuss about gay marriage in the UK. I suggest this is selection effect on one or both of our parts.
I used to think that wild flowers were a cute and unassuming gift and generally not a big deal until I had an occasion to participate in a confiscation operation at a train station. We chose to seize a load of snowdrops from Crimea on St. Valentine's day and have the press make the event into propaganda of nature conservation. Even then I still hadn't entirely abandoned the stereotypes I got from pop culture. What we were going to do was just another drop into the ocean, and not a necessary one at that.
But when the middleman whose plants we confiscated dem...
I always thought that Insulin resistance was bad, always & forever, & that anything that increased Insulin sensitivity was good. But now I've realized this isn't necessarily true. When fasting, the peripheral tissues (fat & muscle) SHOULD become Insulin resistant so that Glucose is spared for the brain. Further, high insulin sensitivity in the morning could be BAD because Insulin is either going to help calories get stored in Fat or Muscle, & 1st thing in the morning, who has produced the proper stimulus to preferentially target those calories to the Muscle? What we really want is a selective Insulin sensitizer and/or timed Insulin sensitivity (eg, after a heavy workout).
There's a lot of background mess in our mental pictures of the world. We try and be accurate on important issues, but a whole lot of the less important stuff we pick up from the media, the movies, and random impressions. And once these impressions are in our mental pictures, they just don't go away - until we find a fact that causes us to say "huh", and reassess.
Here are three facts that have caused that "huh" in me, recently, and completely rearranged minor parts of my mental map. I'm sharing them here, because that experience is a valuable one.
