Physics

when we use water to produce electricity(hydro-electricity)do water get exhausted. that is the quantity of water will change or not

we can use water to produce electricity constantly.if the quantity of water dont change we can use the same amount of water repeatedly to produce electricity. If the above statement is true we can use this above technic in bikes.(ie)use water to produce electricity when it does not get exhausted.... though i have a doubt ... producing electricity with water is large scale in that case it cannot be used in the bikes but is there any alternative can hydro electric project be used on small scale as small as a petrol tank in bike or a litter bigger

once we people thought that the atom is indivisible.But now we have protons,electrons,neutrons and so on..what happens if we disintegrate the protons(say for example)maybe we can find a new elementary particle which combine with many other of such particles to form a proton.that is proton is consisted of???? May be an expert can answer my ques

I have got an idea about making man to fly around. As Neil Armstrong said one can jump very high in the moon. That is because , the gravity in the moon is 1/6 that of Earth. Let us consider the gravity in the Earth to be 1. If we can increase the gravity by 5 or 6 and practise there ,we might be able to fly(jump very high) about in the Earth. I want some suggestions about my post.Reply me.

excerpts from the NYT article: http://www.nytimes.com/2008/10/08/science/08nobel.html?hp " ...Yoichiro Nambu, of the University of Chicago’s Enrico Fermi Insitute, will receive half of the 10 million kroner prize (about $1.3 million) awarded by the Royal Swedish Academy of Sciences. Makoto Kobayashi, of the High Energy Accelerator Research Organization (KEK) Tsukuba, Japan, and Toshihide Maskawa, of the Yukawa Institute for Theoretical Physics (YITP), Kyoto University, will each receive a quarter of the prize..." "...for their work exploring the hidden symmetries between elementary particles that are the deepest constituents of nature..." "...in th…

what is a simple difenition of quantum mechanics?

I've not really studied much about this concept, but Lagrangian Mechanics seems pretty cool. In fact, the most I've really dealt with it is in Klaynos's blog. However, I don't quite understand why the Lagrangian is used. What is the physical significance? Why T-V? If I were to go about making equations of motion, I think I'd use the Hamiltonian (H=T+V). It just seems like the sum of the potential and kinetic energies would be more useful than the difference.

or go back in time?

What materials are able to reflect/deflect microwaves, if any?

I could probably come up with something close to true, but for the smartys out there... Can anyone explain why a bullets spin adds accuracy? In good words and not mathmatics please.

Now - I know how daft this must sound, but I HAVE experienced this for a few years now so here goes: At work, we get a very poor mobile phone signal (out in the country). The best (and often the only) way to get a text message to send from my office is to go right to the corner of the office (Where the toilet is) and hold the phone up high. Fair enough. - Now - some days the signal gets weaker and doesn't register on the phone at all, even when held high in the far corner of the office. On days like this, I find that I can usually get a message to send if I A)-hold the phone up close to an electrical conduit, or if that fails B) I hold the phone next to a tap of r…

the other Day my girlfriend became suddenly all worried that in around 25 years the world will end, because of a meteor/comet/asteroid was on course to hit the earth, and even if it didn't hit earth that it would still 'destroy all life and any known ecostructures'. Now i'm no professional with the matter but i'm fairly certain that there are many things like the former that aren't true. will it happen? is it likely to happen? i'd just like to 'run' it through with some one who knows better than myself thanks J

Everyone knows that the index of refraction of empty space is 1. But, as I understand it, space is never truly empty. Even if there weren't photons, neutrons, dark matter, regular matter, etc, there would still be virtual particles. Since virtual particles are created as matter/antimatter pairs, and some of them will be charged, a photon moving through that space would move any charged virtual particles due to its electric field, so that some of the photon's energy will be temporarily transferred to the virtual particles. That should slow down the photon. I suspect that such an effect would affect different wavelengths to a different extent. A side effect of the above…

http://www.space.com/scienceastronomy/lightning_backgrounder.html I have some questions from the article linked above. 1. If lightning seeks an easy path to the ground, why does it branch, rather than stay as one thicker bolt? 2. If lightning is seeking a path to strike ground, does that mean the positive charge higher in the cloud has been depleted? 3. If lightning sends out a stepped leader, then how does a multi-branching occur? 4. The article mentions one return stroke from the ground, but how is that possible on a multi-branched lightning? Wouldn't that be several return strokes occur from various locations at once? 5. If lightning heats …

Hi all ! and thanks for the replies to the related preamble post "Metal under the hot sun" found here: http://www.scienceforums.net/forum/showthread.php?t=35416 Let's imagine... Metal pipe(s), say 10cm ⌀, vertical, blackened, say 3metres long, vents at the bottom, exposed to sun heat. A nozzle misting seawater inside from their tops. Flow calibrated to always have a little brine draining at the bottom. A shaded wind cooled condenser at the top of the pipe(s) to collect evaporated water. There is room for some improvements as transferring the condensed water warmth to the incoming cool seawater with a exchanger, etc. but let's ignore those. There is …

Sixty Celsius is about the maximum you can handle without burning your hands... That piece of metal left under the sun, or a car bumper, or the beach sand can burn your skin but the ambient temperature is only 30 Celsius. What is going on ? How does the metal gets way hotter ? It is not only the thermal conductivity from the material-to-skin; it is truly hotter. Or seems to be

Hi, We've got this project in science class where we have to make these cards about periodic table of elements and I am doing the part - or the how-to - find out about the structre of atoms out of the periodic table of elements. Now, since these are cards, it needs to be kept simple, but as complete as possible (with images and all)...My question simply is, what is the step-by-step procedure (like, what to look at first), to tell the maximum about the atom's structre on any element of the table. Thanks in advance.

http://www.physorg.com/news141394051.html

Just encountered an interesting article that suggests a neutron bombardment method might, in a couple of decades, be able to speed the decay of radioactive waste in hundreds of years. http://www.sciencedaily.com:80/releases/2008/09/080922100148.htm If so, this would be a great development, and would enhance nuclear fission as an energy source. Anyone got any further information?

Now there is an interesting thought, possibly worthy of its own thread. What happens when your photon is large enough that the expansion of the universe would "split" it in pieces? Or would it be impossible to get a photon with less than the Plank energy, giving it a maximum wavelength? But then what happens when you red-shift that photon?

If I had a piece of string that was about 2mm thick but infinitely long it would have infinite mass. But, if you had two pieces of string like this would yours have twice the mass of mine? If so, how? Because my string still has infinite mass. And another thing. How is it possible to see light from the very very early Universe when surely the light that we are observing should have reached our current location in space long before the mass that makes us up did?

I'm just now learning about the experiments done in Europe right now. I was wondering if anybody could comment something about it, explain something, or really anything would help. I am currently researching it for a physics assignment, but personally I have become too involved to stop learning about it. Any comments would help...thanks -Matt

What is a point charge? I read that it is hypothetical an it hasn`t got any dimensions, length, etc. The article even mentioned that for that reason its density is infinite. I am really confused. Could you please explain to a beginner? Is it a charge smaller than an electron and what do they use it for?

I am trying to solve for the temperature/pressure profile (w/ respect to time) of a gas diffusing into a vacuum. This is analogous to a partitioned container (punctured wall in the middle) with the first chamber being held at constant temp/pressure (e.g. sensors + valves introduce heated gas). Essentially, I believe that the pressure and temp. will increase w/ a decaying rate towards the eventual steady state. I have attached my first attempt at solving this problem along w/ a diagram illustrating the scenario. I believe that it is wrong b/c at eqn.4 I assume that Temp. is constant. How can I resolve this? Any help would be appreciated. Alternatively, are they…

Hi. I suffer from chronic ill health, migraine headaches, ADHD, arthritic pain, depression, chronic fatigue, lack of sleep, lack of alertness and other depressed immune conditions. After many years search, the cause of my sickness was diagnosed as technological pollution. Technological pollution, in the form of electromagnetic fields emanating from electricity, microwave towers and our AC wiring system. Please tell me what I can use to measure and record these fields as I go about my day to day activities. I would like to record every time I come into contact with a frequency or field that is of a strength that would be harmful to my immune/ nervous system. It would be gr…