/sci/ - Science & Math

[Anonymous No.4627393]

ITT:

we post little factoids that will simply and quickly explain, clarify, or dispel ideas commonly held (or not commonly held) by the public.

example:

people commonly believe that gravitational tidal forces and pressure are the reason why the earth's interior are hot/molten and why they stay that way.

It turns out that it has almost nothing to do with gravitational tidal forces. Tidal forces play an extremely miniscule role in the heating process and this effect is essentially ignored in high level magnetohydrodynamic simulations and modelling of the various mass and energy transport processes that occur inside of the earth's interior.

the heat is almost solely the result of the decay of radioactive nuclei in the earth's interior.

there are various ways that you can prove this to yourself, but my source is from a geology class and a geology textbook.

as a side note, this "factoid" was actually presented in that class in exactly the way that I am presenting it now: as a sort of "clarification" of a misconception held by laypeople.
I think the main issue is that the idea of tidal forces as the source of heat in the earth comes from Science Fiction.
it may be true for Mercury or the moons of Jupiter, but it is not true for Earth (or the Moon for that matter).

[Anonymous No.4627413]

this one is more of historical interest.
One of the most closely held secrets from the early part of the cold war, before the advent of sophisticated satellite systems (about the time when the US used genuine chemical film cameras mounted inside of spy satellites, necessitating flying airplanes with nets behind them to catch the film as it falls to earth)...

Extremely accurate topographical maps of the proposed courses of ICBMs, along with geological data concerning the mineral composition of the surface of these routes.

ICBM navigation required purely inertial or star-based navigation back in those days because satellites did not exist to allow for remote guidance.

in order to achieve this, the guidance was performed by computers that were built into the missiles/warheads, rather than by computers located in a command center and beamed by radio (and reflected by satellites).

One of the pieces of information required to effectively program a high precision guided trajectory is the value of the gravitational acceleration (~9.8 m/s^2 on the surface)

they needed that number extremely accurate. That number varies according to altitude, even if it only varies minutely. Furthermore, it also varies according to topology, as the mass of mountains and water affect its value at a particular altitude above the ground. Hell, even the geology affects it, as the density of the rock on the surface below a flying missile will subtlely change the value


Thus, for the period of time between about 1950 to 1970, the US had the best guidance capabilities because we had the most accurate topographical maps of the earth, and hence the most accurate determination of the value of g (NOT "G," lowercase not uppercase) at all relevant points.

This information was also extremely relevant to the operation of spy planes like the U2 and the SR-71/A-21 which also used inertial or star based navigation.

[Anonymous No.4627418]

Almost all pharmaceticals operate by interacting with proteins or carbohydrates that are on the exterior of the cell.


extremely few pharmaceuticals actually enter inside of the cell and perform biochemical processes (typically enabling/disabling a protein which behaves as a sort of "switch" for a particular biochemical process).


There are a few exceptions (notably chemotherapy drugs) and they typically always require extended/continuous, repeated, massive doses of the drug in order to have a serious effect.


Gene therapy drugs do not require that because they are essentially "targeted" by the viruses that deliver them to the cells.


But pretty much anything you buy at the store, or get prescribed by a doctor, will only interact with the outside of the cell.

[Anonymous No.4627430]

this one a lot of people on /sci/ understand implicitly, but its a misconception that many people have due to the limited explanations given in popular discussion.

when people discuss the "inflation of the universe" most people seem to be unclear as to the specific meaning of this.

many people (i know this from hearing people ask the question) wonder if it actually means that the distance between every point in the universe is increasing, such that the fabric of reality is actually stretching apart.

In truth, the inflation is a process that predominantly effects the distance between astronomical objects like galaxies or, less significantly, solar systems, and is essentially unmeasurable in terms of expansion of the distances between planets in a single solar system.

[Anonymous No.4627434]

>>4627430

One way I always imagined it was that all of the galaxies are "flying apart" in some hypothetical spherically symmetric radial explosion. Just like the galaxies were all particles that exploded out of a single point (the big bang)

[Anonymous No.4627441]

>>4627418

lolwut

[Anonymous No.4627446]

>>4627430
I just always assumed there was too much mass counteracting the expansion within more local objects like galaxies or star systems, that in deep space expansion continues at a rate much higher.

[Anonymous No.4627458]

>>4627441


drugs typically interact with the outside of the cell. Rarely are drugs designed to actually go inside of the cell.


There are a handful of drug types that do require this, but they are the minority in the spectrum of small organic molecule therapies.

[Anonymous No.4627503]

>>4627430
a little experiment i remember doing in elementary school to demonstrate this was drawing galaxies on the outside of a balloon and blowing it up.
the galaxies remain relatively unchanged in size but the distance between them increases significantly.

[Anonymous No.4627517]

>>4627458

But that's wrong, depending on how you define handful. Obviously the penicillins are an important drug class, and act on the cell wall, but there are numerous drugs that target bacterial enyzmes, ribosomes, DNA, etc.

[Anonymous No.4627521]

This is a nice thread and I enjoy reading about these types of things..I would contribute but I absolutely hate typing when high. But here are some boobs.

[Anonymous No.4627538]

>>4627413
Pretty cool actually.

[Anonymous No.4627540]

A popular misconception is that language is essentially a cultural creation that has to be learned completely by a human, like, say, playing the piano has to be learned. In reality, we are endowed by birth with an understanding of the more fundamental principles of human language; as infants, we just need to learn the details.

[Anonymous No.4627547]

Not /sci/, but...

There's a myth about the origin of money. It goes that
1) first there was barter. This was inconvenient, so eventually
2) money was invented to facilitate trade. This was the constant until
3) credit was developed in modern times.

In actuality, we've yet to find a society based on barter, nor do we have any historical accounts of societies based this way.

Although the means of exchange vary between early societies, one of the ways (eg in Sumer) that people exchanged goods was through credit. Credit predates money, not the other way around.

[Filosofer scientist linguist No.4627574]

>>4627547
That's interesting.

[Anonymous No.4627573]

One you probz already know... buttttt A rain drop isn't shaped like an upside down icecream cone like it is usually drawn. They more resemble a sphere

[Anonymous No.4627585]

Here's one, I don't know how common it is but I heard my grand mother say it a couple years ago and didn't say anything to her about it because she's old.
When it rains over the ocean, the water coming from the sky isn't salty. If you ever have a container with salt water and let the water evaporate the salt stays in the container. Also, I live on the east coast and every summer there are a myriad of hurricanes. If this were true, then when the storms come on land and rain comes, it would kill everyone's lawn (Despite the movie Idiocracy, plants don't like electrolytes)

[Anonymous No.4627601]

>>4627585
Are you some kinda retard?

[Anonymous No.4627611]

>>4627601

It doesn't rain salt water in the ocean. Are you trying to tell me it does?

[Filosofer scientist linguist No.4627613]

I wrote about this some time ago. http://emilkirkegaard.dk/en/?p=2816

Here are some good things to read to get rid of misconceptions about various things:

http://en.wikipedia.org/wiki/List_of_common_misconceptions

http://en.wikipedia.org/wiki/Misconceptions_about_HIV_and_AIDS

http://en.wikipedia.org/wiki/List_of_common_false_etymologies

http://en.wikipedia.org/wiki/Common_English_usage_misconceptions

http://en.wikipedia.org/wiki/List_of_misconceptions_about_illegal_drugs

http://en.wikipedia.org/wiki/Common_misunderstandings_of_genetics

http://en.wikipedia.org/wiki/Snopes.com – www.snopes.com

http://en.wikipedia.org/wiki/Skeptic%27s_dictionary – http://www.skepdic.com/

http://www.amazon.com/Great-Myths-Popular-Psychology-Misconceptions/dp/1405131128/ref=sr_1_1?ie=UTF8
&qid=1333843699&sr=8-1

[Anonymous No.4627617]

>>4627611
You fucking think that rain anywhere near the coast isn't going to be salty? I live in Sacramento and the rain here is even salty as hell.

[Filosofer scientist linguist No.4627635]

>>4627585
But they don't like electrolytes in Idiocracy either. That was an important plot element. So, i don't understand the use of "despite" in that context.

[Sage No.4627646]

>>4627617
Go to bed Stuarrt.

[Anonymous No.4627652]

Kind of obvious, but I feel like contribootin' and at least I wouldn't be a samefag.

It's a common misconception that the seasons are caused by the eccentricity of the Earth's orbit around the Sun, since at certain times of the year it is closer or farther, causing a temperature variation. However, this actually has little to no effect--so much that the earth is actually CLOSER to the sun in the winter (as according to the northern hemisphere, whose seasons dictate the naming of such things as the summer and winter solstices). The seasons are actually caused by the axis tilt of the earth facing the sun, making it so less direct sunlight is able to reach northern hemisphere landmasses during the winter, when the tilt causes them to face away from the sun.

[Anonymous No.4627660]

>>4627635
Derp?
You expect someone who thought salt doesn't evaporate out of ocean water could effectively understand a Mike Judge plot?

[Anonymous No.4627697]

You all are dumb asses if you really believe it rains salt water ANYWHERE

[Anonymous No.4627723]

>>4627413

I know a guy who flew a DC3 with the inertial nav system from a cold war era submarine over antarctica to determine the extent of the land under the ice layer

[Anonymous No.4627741]

>>4627652

more specifically:

angle of incidence
atmospheric obstruction
length of day/night cycles

I saw a documentary in which a bunch of high school/college students were asked, and they didn't know

[Anonymous No.4627775]

Um, I'm no scientist, but I do know that when you evaporate salt water, the salt doesn't evaporate.

[Anonymous No.4627785]

>>4627775
One nondumbass here