pavelcherepan

I think it's very much cultural. Say, in Taoism philosophy males are associated with white (yin) and females with dark (yang) forces. For a long period of time men in many cultures have been associated with the planet Mars and hence with red colour. Also, according to the web page below the association of boys with blue colour is very recent coming from mid-twentieth century. http://jezebel.com/5790638/the-history-of-pink-for-girls-blue-for-boys

"-- I know kung-fu! -- Show me" Not as far as I've heard of. I think that our general understanding of how brain works with information is pretty poor, so it would take a long time until we're able to read/write memories. There are several models of how memory works, for example: http://en.wikipedia.org/wiki/Atkinson%E2%80%93Shiffrin_memory_model http://en.wikipedia.org/wiki/Working_memory

What kind of causality dilemmas are you talking about?

One thing is that sunlight not only triggers photosynthesis, but also controls other processes in plant growth. Luckily, this has already been done by using an artificially created substance that made plants "believe" they are in sunlight while in fact they were kept in total darkness: http://www.kit.edu/kit/english/pi_2012_10419.php http://www.plantcell.org/content/early/2012/05/10/tpc.111.094656 In the experiment I referred above researchers didn't administer any sugars to plants, but it seems quite reasonable to assume that since plants can technically survive in darkness for a bit it's possible to develop nutrient feeding system that will allow them to grow in darkness too. I haven't seen any links to such experiments, though.

I do believe that physics generally doesn't concern itself with question of "why", but mostly tries to figure out the "how" part. As far as experiments on relativistic mass are concerned please have a look here: http://en.wikipedia.org/wiki/Tests_of_relativistic_energy_and_momentum http://en.wikipedia.org/wiki/Kaufmann%E2%80%93Bucherer%E2%80%93Neumann_experiments Also, if you're interested below is the link to a paper describing an apparatus to measure relativistic mass increase: http://www.dickinson.edu/download/downloads/id/55/apparatusmeasuremass

I think you need to define the frame of reference first. Is it sun-centred, Earth-centred or uses some other point of reference? Because in different reference frames velocities of Earth and Moon will be different and the momentum will be different as a result.

Guys are working with hazardous substances and are working on gold refining which to me implies some monetary gains, so legally they should be registered as a business of some sort. And if they are registered as a business then all provisions of workplace health and safety regulations apply to them to a full extent. Additionally, chemicals, especially such hazardous, should come with some form of material safety data sheet (MSDS) or product safety data sheet (PSDS) issued by the supplier. Such data sheet would contain most information on handling and safety procedures relating to a particular substance and information on hazards that can arise from using, storage and handling of the substance. So the first place I'd be looking to answer the question in the OP are MSDS's for acids in question. Addendum: I had a look at EU safety data sheets and this is what I found for substances in question: HCl: Sulphuric acid: Nitric acid:

Interesting project indeed. Still, a slight bit of nit-picking to follow. In your video you said that ESA attempted a landing on an asteroid, while in fact it was a comet, which is in my mind is slightly more complicated because surface features of a comet, unlike that of an asteroid, are prone to changing and these changes can be rather fast especially in the vicinity of the perihelion. Also the "failure" of Philae lander was not a result of poor landing accuracy, but a result of it bouncing off the surface twice. It bounced quite high, up to about 1 km above the surface, as a result of just ~38 cm/s excess velocity on landing. The main reason for the bounce seems to be that harpoons that were supposed to hold it on the surface were not deployed in time, so technically it has little to do with poor accuracy of landing.

Thanks for your responses guys! Probably you're right. I was just making some wild guesses This makes a lot of sense. Thanks!

Hi everyone! Today I was watching a performance by Tokyo Philharmonic Orchestra at NHK Symphony Concert Hall building and got this question. As you can see in the image below the concert hall looks pretty fantastic and what you can notice straight away almost everything is either wooden or covered with wood. I sort of understand the idea behind this: since for many if not most of orchestral instruments sound is created amplified within a wooden chamber, if afterwards it is reflected by a non-wooden surface if may change its characteristics somewhat compared to the original. Hence in order to preserve the proper sound its wood all around. But anyway, does this have any physics basis? Would sound characteristics change if reflected by different surfaces?

Too many groups of people with greatly varying cultural backgrounds, beliefs, religions and traditions. It's less noticeable on a scale of a single country, but even then especially with larger countries you have huge regional differences and separatist movements as a result. Take China or Russia as an example. This will be by orders of magnitude more visible with a world government. It would be extremely hard to develop laws that would be acceptable to all groups. Or if you make laws that differ greatly between regions then the whole system will be more like a confederacy which is not exactly a single entity.

MigL, just a note that when safety management is concerned engineering solution is always more desirable than PPE. Eliminating the hazard altogether is even better, but PPE should only come in play when all other measures fail or otherwise impossible to implement.

Cool, haven't seen this one! Thanks StringJunky!

Moving to other planets won't help with overpopulation, because initially only a limited number of colonists would be able to come and once the colony becomes big enough and starts to have population growth, only limited amount of newcomers will be able to arrive due to limited resources. How do you plan to move carbon dioxide? Wouldn't it be easier to get stuff from near-Earth asteroids. Mining and processing regolith is awful and can only be feasible if nothing else is available. Energetically, going to NEOs is slightly more demanding than the Moon, but your output will be better. Plus in the initial stage you want your self-replicating robots to increase in number quickly, and that is easier to do when metal is more readily available and easier to process.

I don't think double slit experiment has ever been done using single separate particles, although the theoretical idea is that the particle/wave is supposed to interfere with itself. Maybe I'm wrong, though.

Please explain what you mean by spinning an object? Say, if I take a gyroscope and spin it really fast, so that outside edge is doing the velocity you mentioned, will it levitate?

I highly doubt that that's the case. Personally, I didn't chose to forget my dreams and, yet, I can't remember a single one. I think posters above gave much better explanations.

Quarks are normally colour-confined within hadrons and so under normal conditions can't really exist be seen in free state so I'd say no.

Considering the difference in isotopic composition between Earth and Mars, for example, it's very likely that it is quite different on the Ceres too. But such difference wouldn't mean that it would be unusable for some reason, it's just that it's supposedly quite some distance below the surface.

I have watched just a small bit of the video, but I'm pretty sure that most things in the video have been discussed and explained in this pinned thread: http://www.scienceforums.net/topic/15439-welcome-creationists-to-science-forums-and-debate/ , creationists don't usually come up with anything new and interesting. Use argumentation from that thread if you want to argue with the guy, but I rather doubt there is a point in it. Creationists rarely listen to logic and scientific reasoning.

Below is the link to a video, where Elon Musk is presenting Tesla Power Wall. I've linked to the section starting at 2:41 where he talks exactly about how much area you'd need to provide solar power for the entire world with some pictures too. https://youtu.be/yKORsrlN-2k?t=2m41s At about 4:50 he talks about how much space is required for batteries (since solar power is useful only for half the time).

Nice, but do you have an actual question people might help you with? Btw, the reaction is not balanced, there should be a 2 in front of hydrogen peroxide.

Unfortunately, my couple attempts to learn Latin have ended in disasters so I have to resort to the English translation, which gets a bit confusing at times. I've read quite a bit about Ghenghis Khan' campaigns in China and also quite a bit about the Golden Horde, but thanks for the suggestion, I'll definitely have a look at that one!

Commentarii de Bello Gallico - absolutely fantastic read about a really interesting period in history and written by the man in charge. While no being very descriptive of the surroundings and general life in Gaul, Caesar gives some great insights into local politics in Gaul at the time and first-hand view on all the battles and sieges. It's written in a slightly weird manner with Caesar referring to himself in a third person and also uses some pronouns, specifically "he" way too often, especially considering the fact that he refers to himself as "he" too. In many cases this makes it a bit hard to understand who he's actually talking about. But it's still a really awesome read, wish I'd read it sooner, and after I finish this one, Commentarii de Bello Civili is going to follow EDIT: Before reading the book Caesar in my personal rankings held top marks for his skill as politician and tactician and slightly lower for strategic planning (due to being cut off from supplies and reinforcements in Greece and besieged in Egypt). After reading, though, I have even higher regard for his skill of tactician, because winning battles against overwhelming odds and such a blatant disregard for reconnaissance is nothing short of brilliance. Twice being ambushed by an army that he's been chasing? Being besieged, while besieging a city himself? Really?

If you want your "equation" to balance then there should be same entities on either side of the = sign. You can't balance an equation where you have meters on one side and apples on the other, hence units should be same, and then your negative volume can't exist.