Physics

Dear sir, I have a question with domestic water purifiers. There are different types of water purifiers 1. Use candles for filtering 2. Use UV light 3. Combination of both. 4. Reverse osmosis. Manufactures recommend reverse osmosis based is the best. I think in RO process all minerals are removes. Is it advisible for drinking. If not. Which is the best. Doctors advice boiled water is the best. Pl guide me. Thanks Murulidhara

We know that energy can be converted from one form to another. Also mass can be converted to energy. Can energy be converted to mass?

Ok you guys got to get one of these!!! I just bought one, and these lasers are bad!!! you guys got to get one!!! Go here and check them out: http://wickedlasers.com/index.php?promo=4433 This is great to do experiments with..... And study... You can touch the sky with this thing.... Only two AAA batteries power this thing, you got to see it for your self... If you guys do buy one use this promo code: 4433 and use the add to basket button.... But if you click on the link above you should already have it activated.... THIS WILL GIVE YOU 5% OFF YOUR LASER!!! These thinks are bright!!! You can point out stars in the sky with it.... And it can…

does anyone out there heard af any processes that create uncontained vacuums? i tried searchin all over and all i found was a form of weapon what creates this, "BIG BLU" weapons which include the "moab" heres whats said about it "Basically explosion eats up all Oxygen in the blast area as it explodes outward in a fireball, creating a large uncontained vacuum. If you survive that, the zero pressure area sucks air back in at 2000 MPH" so it is possible to create an uncontained vaccum, its just maintaining it, any ideas at all?

Can someone help me understand "stationary waves"?

hi guys, i am having trouble with this problem. Calculate the average force of friction acting on a wood block as it is propelled along the floor by an elastic band ? my solution and my ideas: What does it mean by average froce of friction? I first weighed the peice of wood to find its mass. i then used a newton scale and pulled the elastic band 60 cm and found the force of friction which was 8n. is this force applied(8n)?did i measure the force correctly of the elastic.?i have no idea where to go from here. is there any kinetic energy involved? do i use Ek=1/2 mv^2. any suggestions would be helpful. do i time the wodeen block after i let it go and find the veloci…

Women astronauts do not wear brassiere up there, do they?

Would it be possible to make a rechargeable nuclear battery? You know, the kind of batteries that last a super, super long time. Is there a rechargeable type? Can a rechargeable type be made? How possible would it be to recharge one? How long would it take to recharge? Months? Years?

As I understand magnatism as with electric feilds, electromagnetic waves and graverty all conform to a rule that states that the force acted on an object by the source (planet\magnet ect...) is equal to the inverse square of the distance away from the source that the object is. Ferrite magnets are week whereas neodym magnets are relitivly much stronger. Magnets use ferromagnatism to interact with each other. There is also another force I think called paramagnatism that is a metal object that is not itself a magnet being atracted to magnets. Mostly thease two forces seem to act as once force. However there is one instance where they can be seen together acting …

I'm new at these forums so feel free to correct me. I need to calculate the number of oxygen atoms in a volume of water and oxygen gas near sea level. (at the same temperatures say 70 F). Thanks for the help!

Is it possible that at the center of the earth there is nothing? I think that there may be empty space. If you were a partical of mass at the center of the earth would you be gravitationaly atracted to the largest amount of mass. This mass would be in any direction towards the surface and you would be pulled away from the center. you would also be atracted equally in the opposit direction and these two atractions would cancel each other out and you would be weightless. Lets take a look at a molicule that is two miles from the center. It would be atracted to the mass that would be closest and that would be in the direction away from the center of the earth thus…

Hello! I hope my post does not breach forum ettiquette, I am new, please, no flaming. I would like to calculate how much energy an object(a horse, for me) expends over a given distance x, at a speed y. I would then like to compare this with energy spent over the same distance x, when accelerating to a maximum speed of y from an initial speed, a. Can anyone help, or at least make sense of my humble request? Tourist.

i was doing my physics homework (again) and i was wondering (again) if warm air rises shouldn't the sky be warm? say for example, you're flying in a plane and as it gets higher it gets colder and harder to breathe. is there like some kind of wall that stops warm air from rising higher into the atmosphere. I found out that cool air falls-shouldnt that make the ground like freezing? > > >

Hello. This contraption keeps its flotation and its forward motion from the operator's movement; what mechanical actions and reactions are involved, and how does each element performs ? Miguel

For instance when I go to turn off my monitor, I have the off button on the monitor BTW, when I hit it I imagine that I transfer a bit of energy to the button and the monitor. When this energy is applied on say the molecular level of the button or monitor itself, does the energy propagate out, or is the reaction or action for that matter based on every atom itself reacting basically. Lastly, how long would a amount of energy(quanta?) spend in a single atom, or for that matter a couple of atoms and what does this this have to do if anything with the bonds they may hold with other atoms? Example is say you blast a piece of metal with an AP round from a rifle, the metal…

As there is no topic on this rather intresting peice of software I will create one. http://learn.arc.nasa.gov/vlab/index.html It's basicly a virtual microscope. A bit like the way google earth looks at the world you can look at verry small stuff by downloading sets of images whitin the program and zoom in on interesting bits. Some files also have the abbility to change though levels of focus as well or fade in and out the same image but photographed using a diffrent tecnology. Various samples to look at.

I don’t really know where to place this thread, and I know I come up with lots of odd ball ideas it seems but hey at least its something out of the norm at least. I would like to reference this question to the big bang and the evolution of matter really. After the big bang and the subsequent time the elapsed until the common matter today came about, or matter with mass, examples being the proton for electron for instance, or carbon or oxygen, is it really a random assortment type of process that lead to this? What I mean is say you have the big bang, boom, and then what lead to matter and mass for instance? Was it a guaranteed process to get electrons and protons, an…

If I had a mixture of say two elements that were stable and in a solid state, when I heat them to a certain point, or perhaps cool them to a certain point is it possible to simply break the bonds that hold them together? I mean I think its a pretty simple question but I have a more reasonable explanation to why I ask. From study I have learned that atoms get exited by energy, or rest basically in the absence off. So then it would be reasonable to assume that maybe on a subatomic level change is occurring in relation to the energy in the local environment, such as is its very hot or very cold. So then thinking of "quantum leaps" really in terms of atomic structure if I hav…

When you blow a small flame(e.g flame of a candle), it can go out. Wouldn't the extra oxygen help the flame blow bigger.

The threat title sucks but I couldn't really fit much explonation into that space. I once used a device that was a small handheld box with a speaker and a volume controll on the front it. The sound waves that came out of the speaker when it was turned on was the same the electromagnetic waves travevling though the device. The end result was that just by listening you could hear distant thunderstorms you couldn't hear with your ears as they where to far away, somone who had a watch with a magnetic pendulum inside it could be heard from about a half meter away, fuzz generated by TV sets which where meters away (and there where flat screen), sets of bleeps make by pr…

Has Nikola Tesla's experiment of tranmitting energy via the ionasphere been repeated succesfuly under lab conditions? If it were possible, how might this work? Any other insight into Tesla's experiments would be appriciated, his claims seem a little too out there, and should either be dismissed, or corroberated with serious scientific scrutiny. thanks. Tom

Why cant see the stars when its snowing/raining? Thanks

For a long time, I have wondered about the following condition, mentioned in textbooks and elsewhere, but never fully explained (at least not to my satisfcation). Objects exposed to ionizing radiation, such as x-rays, gamma rays, and the sort, tend to become sources of radiation themselves (radioactive) upon removal of the original source. How true is this? What conditions must be met for it to occur? If true, why is the equipment in hospitals' x-ray facilities not secondarily radioactive? Or is it, to some degree? Information would be appreciated! imp

During my physics tutorial session recently, I remember a girl asking a question that she said her dad asked her based on physics that seemed to make us step back a little and think. So I'm sure you may enjoy it:-) Ok basically its kinda 2 questions. What is it that causes the Earth to spin, is it some remnant of angular momentum that still exists since its creation. or is there some other explanation? Also Why is a pendulum that is stationed on the Earth's surface unnaffected by the Earth's spin? Or is this incorrect? I could imagine explanations to these questions like to a good approximation we can assume the pendulum to be within an inertial frame, or that t…

No idea where this should go, but i thought it was quite cool (sorry if this is well-known to phisisists): http://www.as-e.com/products_solutions/z_backscatter.asp http://www.youtube.com/watch?v=pAldBxgRCdY afaict, it assays materials' ability to scatter x-rays and so measures stuff with low molecular weight (people, drugs, explosives etc) which apparently are more inclined to scatter x-rays, whereas normal x-ray scanners (like you'd find in a hospital) i think measure things based on their x-ray-adsorption, and so measure stuff with a higher molecular weight. or something. apart from thinking that this is interesting/cool/like sci-fi x-ray specs, i have a qu…