CaptainPanic

Have a WOO YAY! Congrats!

What is pressure? The book that your teacher told you to read says: pressure is force / surface [math]P = \frac{F}{A}[/math] The unit of pressure is the Pascal, which is identical to 1 Newton per square meter: [math]Pa = \frac{N}{m^2}[/math] - note that the formula and the dimensions (units) correspond perfectly - that's no coincidence at all. You also know that force is weight multiplied by the (gravitational) acceleration... [math]F=m\cdot{a}[/math] or [math]F=m\cdot{g}[/math]. That should give you enough clues.

If ET has the same attitude as us, we'll never find them: We have a project to search, but we're going to scrap it after less than 1 century. What if ET is just taking a century-long lunch break? What if they only decide to broadcast some message to us once they received a signal from us? We only transmitted the first signal about 1 century ago! Our current signals are a lot of noise from many sources that broadcast on the same frequencies. Do we even know if ET will find us, if he/she/it receives the signals we're creating now? Within the 1000 lightyear area around us, the majority of the civilizations (if there are any) don't even know that WE are intelligent enough for basic space flight and even radio.

That is a good keyword to get you started on maneuverable helium devices: blimp. Next thing you need to check is the total stored energy per kilogram of compressed air, and compare that to your other options (if you have any). There is no reason why it does not work - in theory you can just make the blimp bigger or the air cylinders smaller... it will reduce flighttime, but will still work.

While solar heat provides a lot of energy, you should realize that you'll be harvesting only a portion of the sun's energy. The sun will provide in the order of 1000 W/m2 on a sunny day. Because of the Carnot efficiency you will only be using 30% of the sun's energy that is converted to useful heat. In practice, I think you'd do very well if even 10% of the sun's energy is converted into kinetic energy... because you will have more losses: friction (air, and all other types of friction), reflection of sunlight and radiation of heat. So, you must either have a massive solar collector, or tons of mirrors. If you plan to concentrate the sun onto your little car: please wear a protective suit, it's gonna be hot! Please remember that while 1000 W/m2 sounds like a lot, It is about 1 hp. (Horsepower = about 750 W - it's a unit which, inconveniently, is often used to describe the power of cars and other transportation devices). Good luck, it's a nice idea.

Dijon mustard?? LOL!!! Just imagine that any other world leader gets into such trouble for eating at McDonald's If this is true, then it's the best joke ever. I say impeach the bastard! He's eating French food!

I believe (meaning I'm not sure about it) that you can power a purpose-built nuclear facility with plutonium from bombs. Which means that while we dismantle bombs, we can actually use the energy. The beauty of this is that there is a real chance that we use up all the nuclear material - again I'm not sure though - because there is a limited amount of uranium on earth. Numbers vary, and it depends on the technology used, but some claim that at the current rate + growth of nuclear power, the uranium will be depleted in under 100 years.

Ah, yes... it is indeed adsorption, not absorption. In deposited ice (which resembles snow), what percentage of the water molecules will find themselves on the outside of a crystal, and what percentage is completely surrounded? (I know that it will depend a lot on many parameters - humidity, temperature, time - but does anyone feel like taking a shot here?)

My guess is that mucus (wikipedia) is blocking your nose. Why the mucus is moving around is a mystery to me. In my personal case, one nostril is always used more than the other.

What is landscape management? Sounds a bit fuzzy to me. Apologies to all landscape managers, but I would advise against such a study. I always advise against a study that would not be missed if it disappeared. If doctors disappear, we're in trouble. If (civil) engineers disappear, we're in trouble. If we don't understand our environment, we can get into possibly even more trouble. If nobody manages our landscape, we have to look at slightly more ugly sights... hardly a real problem. I'd advise civil engineering, but then again, I'm an engineer and I love it (so I'm not objective). If you're creative, you enjoy maths/physics/chem (or you enjoy solving complex puzzles, or possibly you played a lot with Lego ), then engineering might be something for you... although it's hard to say. I'm not sure who you put "civil engineering/business" - they're quite different disciplines.

You cannot have an evolution over billions of years of a species that eats its own natural resources. Humans seem to be capable to finishing all resources in a matter of a few hundred years. I had understood the OP (opening post?) as a question about life that could possibly evolve on Uranus. If we're talking about something that has evolved, then sunlight is the only source of energy that it can utilize - unless this life we're looking for is found on such a tiny scale that it has almost zero impact on the planet... But that isn't possible, because life has one important characteristic: it spreads as long as resources are available.

Sublimation and also deposition change the shape of the ice cubes, although most of the deposition will come from water from outside the fridge (it enters when you open the fridge). About the nasty smells in the ice: Perhaps the old ice has a much larger surface area, and is therefore much more capable of absorbing the nasty smells? Just an idea.

Hehe, I don't care too much myself, but I believe that the starter of this thread (courtneylinae) is now actually using your input for his homework...

You need to find a kind of reaction that runs on sunlight that turns methane into a component with a higher energy. Then your organism can eat that higher component, and exhale or fart methane. iNow, methane from cows is a waste product of anaerobic digestion. The butt of a cow doesn't contain any oxygen, which is why the cow doesn't explode. to my knowledge, no microorganism eats methane in absence of oxygen. The same goes for hydrogen - you cannot have a metabolism with only a fuel, and no oxygen. For a working metabolism, and a working ecosystem, you need to have two equal but opposite reactions, like on earth: Photosynthesis turns CO2 and water into sugars, and all other life turns the sugars back into CO2 and water. Therefore, you'll need two organisms that help each other. One "plant", which utilizes the sunlight and one that just consumes all available "plants".

Got my voting card in today! Other friends (including foreigners from the EU) got theirs as well - which means that surprisingly the bureaucracy is working

Tell it to an elephant. Elephants never forget. (I'm really sorry for this post)

Solid, liquid or gas? And please explain what you need it for - you probably also want a good heat transfer, which means you need to look at a few more parameters than just the type of material. Your description seems to suggest you want to build some kind of solar boiler - please specify this a bit more. One of the materials with the highest specific heat in the world is water - it happens also to be one of the cheapest.

It was live on the Discovery Channel yesterday. I've never seen anything live on that channel before... great improvement. Hope they do more live coverages of scientifically awesome things

An average hippo is 1500 kg. Hippo's sort of float, therefore their density is similar to water. Therefore a hippo is 1.5 m3 on average. 1 mole of hippo's is therefore 1.5 * 6.022*10^23 = 9.033*10^23 m3 in volume. The volume of the earth is 4/3*pi*r^3 = 4/3*pi*(6.378*10^6)^3 = 1.086*10^21 m3 (the volume of the hippos far exceeds our tiny earth). We then must add these two volumes, calculate the total radius, and subtract the earth's radius: total volume = 9.044*10^23 total radius = 60*10^6 m radius earth = 6.378*10^6 So the layer of hippos is about 54*10^6 m, or 54000 km thick. So, not miles deep... more like the Earth becomes the size of Jupiter Sorry for adding a completely pointless post - I just enjoy silly calculations such as these. Time to get serious again.

A mole is a word that's similar to a dozen or a gross. A mole is a number. dozen = 12 gross = a dozen dozen = 12*12 = 144 mole = 6.022*10^23 So, if you have 3.5 gross eggs, you have 3.5*144 = 504 eggs. If you have 3.5 mole nitrogen molecules (N2), then you have 3.5*6.022*10^23 = 2.1077*10^24 nitrogen molecules. But because that number is so ridiculously large, and we never count individual molecules anyway, we prefer to say "3.5 mole nitrogen molecules". Sadly, all textbooks I've come across make a lot of fuss about why the number "mole" is what it is (namely 6.022*10^23) but don't mention that it's just similar to a dozen. In practice, you don't need to know any more than that it's a number.

Molecules in liquid water are moving, shaking and turning all the time... Then you would die instantly... and you, and all the water in the universe would become some kind of salt. But luckily this won't happen until the laws of nature change... so it's pretty pointless to consider. So what "good info" are you looking for? Wikipedia clearly explains that no functioning applications have ever been built. The fact that good info is so hard to come by might be because it doesn't exist. Try finding info about warp-drives. Pretty difficult.

The large majority of nuclear weapons are possessed by a TWO countries: USA and Russia, (Ukraine and other ex-Soviet states handed over their weapons, and all other countries have under 400 warheads which is a lot, but not enough for the destruction of a nation the size of a continent).(wikipedia - List of states with nuclear weapons) Therefore, if Russia and the USA agree together to reduce their weapons, which can be achieved through simple diplomacy, then you can proceed with a MAD on a slightly smaller scale. You can still destroy all major cities, but you can also assure that some part of the land will not be turned into a giant parking lot, thus assuring that humanity and life in general can at least make a re-start after the war hawks had their say.

The most obvious difference is that a fuel needs air / oxygen to combust and explode, while an explosive needs nothing at all, and will just react with itself. In rocket fuel you need to distinguish between 2 types: those that are completely pre-mixed: the solid rocket fuels (which can explode, and are thus in fact also explosives, but just burn slower) and liquid rocket fuels and hybrid rocket fuels which keep the fuel and oxygen separated until it's time to burn it in the combustion chamber. Then there's of course safety. C4 as jet fuel is kinda dangerous. At least normal jet fuel cannot burn unless there's a leak in the tanks. C4 can just react with itself. I guess that material for bombs is chosen by its detonation speed. The higher the value, the more boom you get per weight. Rocket fuels are probably chosen for stability (because it's a rocket and not a bomb, you want it to burn in a very controlled manner - but a solid rocket cannot be turned off again once it's going) and for the most thrust kg of rocket fuel. I'm not sure I understand the second part. If you're asking if the energy released is proportional to the weight of whatever fuel / explosive you use, then the answer is: Yes. It's linearly proportional. I'm not 100% sure how this energy translates into a blast wave or shock wave. Finally - this whole field is very much "don't try this at home". If you ask the types of questions you just asked, then I believe you should study first, and only then consider to do anything more dangerous than a firecracker... tell us about your multidisciplinary project. What kind of project deals with fuels and explosives?

Zero point energy has little nothing to do with this... The water molecules simply attract each other (normally this attraction is called the "hydrogen bond", but you're correct that these are caused by charge differences and can thus be explained as electric fields). So, in short, it is caused by the characteristics of the atoms (oxygen and hydrogen), which determine the characteristics of the molecule. The two bonds between oxygen and hydrogen in water are at an angle of approx. 109 degrees, and because oxygen is very electronegative and hydrogen is not, these two things cause water to be (very) polar. This in turn means that there is a strong attraction between oxygen atoms in one molecule and hydrogen atoms in another water molecule. This attraction sometimes causes the bonds to break. That's the simple version of the explanation. The self ionization takes exactly the same amount of energy... but you don't measure any temperature difference because the equilibrium reaction proceeds at the same rate in both directions (meaning recombination of OH- and H3O+ to 2 H2O is at the same rate as the "self ionization"). I believe (not 100% sure though - interesting question) that water doesn't dissociate ("self ionize") when it's ice... and therefore it won't happen also at very very low temperatures. But finally, this zero point energy is often associated with a lot of BS (using more difficult words, wikipedia says the same)... so my advise is that you don't spend too much time on anything related to the zero point energy because you're likely to find BS (a type of manure which originates from cattle).

The (bio)chemical engineer is the inventor of beer. But chemistry as a whole made life, if you believe in the Primordial soup theory.