Physics

Is anyone familiar with van der waals forces in plasma, and or maybe van der waals forces in general? I need some information on them and google has not been very helpful. any help would be appreciated

Hello, I want to build a circuit primarily for heating. I need some advice on the best things to use like heating resistors, resistor wire and power and some way of getting it working on a USB. I basically need it to be a effective heater for things like water and not take up too much power? Can anyone please help me there is a lot of intelligent people on this forum and i need some help Thank you very much

I think I remember hearing about this years ago, but I cant remember what was said about it. If a bullet is fired into the front of a speeding train, then the bullet has to change direction, which means it will momentarily stop. If the bullet stops, then so must the train, how can this be possible. Is this xeno/zenos paradox?? or how is it connected to it

Although i like to think i understand electromagnetic waves there is still something i don't understand: Why in the case of light waves do some substances not reflect any light out at all (such as glass), i know its because it doesn't 'absorb' the frequencies and therefor photons aren't released, but what is it exactly which causes it to be unaffected by the electromagnetic wave? In the same sense why doesn't all the radio waves and other waves shooting around us drastically effect our body?

I do not understand how the wavelength of sound changes depending on the distance between the moving source and the observer. Its as if the sound waves have foresight as to how far the objects is and adjust wavelength. Please explain.

plz some 1 tell me wat is diff bw heat and temp

For my 10th grade chemistry science fair report (it doesn't have to be about chemistry), i chose to determine the Curie temperature, or temperature at which a material loses its ability to be magnetized, of different materials using the magnetic heat engine. http://www.scitoys.com/scitoys/scitoys/magnets/magnets.html#curie_effect Sounds easy right? Well, my dad and i made a rare earth magnet be pulled by another magnet so it is in the candle flame. When the pendulum magnet is resting at the bottom of its swing, the bigger magnet pulls it until it is suspended. Then once it heats up from the candle, it falls back and never returns. We had no idea why that happened. …

Can anybody give me other examples of devices in which a given type of energy goes in (Type A) and a different comes out (Type B) but when Type B is put in Type A comes out? The only examples I can thing of are an electric motor/generator and a piezoelectric crystal. Thanks!

As mentioned in the title I want to be able to make an electric heater coil that is capable of producing temperatures of 350-400 degrees farenheit with a simple 12 volt car battery? Thanks for the help.

Hi all, Im new to SFN so sorry if this has been discussed, just wanted to know if there was anyone out there who could explain to me how vibrations from sound can be converted to electricity, though Im sure it is possible I cant seem to get my head round it. Thanks in advance.

What are your qualifications? Degree in physics? High school physics? Stuff you read out of a book? Quantum, nuclear, relativity? Post here what kind of physics education you have. I have high school, and half of first year university (my vote was just high school though, I figure half a year doesn't really count). Along with as much stuff as I can learn on my own. My favorite if not nessesarly my expertise is Astronomy stuff. (As an aside, I didn't know before 10 minutes ago that this forum even existed. I have many hundreds of posts, most of the physics forums. But whenever I went to the phyics directory I always went to the subdirectory, like Quantum P…

In 1959 remarkable experiment was conducted by R.Flangan Gary,a physician working at the US navy's centrifuge laboratry in pennsylvania. The Navy was intrested in water immersion as a means of body support to increase tolerance og high g loads. Gary designed a large aluminium capsule that could be fitted to centrifuge and filled with water. He tested himself by climbing inside and, completely submerged, held his breath as the centrifuge wound up and subjected him to a load of 31g for five seconds and then wound down again.

An article published in this weeks newscientist concentrates on a little known theory for joining together general reletivity and quantum theory. http://www.newscientist.com/channel/fundamentals/mg18925331.200.html The latest adaptation uses 8 differnt dimentions, and one of the reasons that this is interesting is that the interactions of 2 of these dimentions can create an anti gravity effect, allowing for a move into a theoretical hyperspace. Unfortunatly dispite this theory being developed for nealry 50 years no one has conducted any experiments into it. It's only evidence is that it makes predictions of the mass of the fundemental particles which fall within…

I posted a message on 1/4/06 (Space Travel Realities) regarding the physical limitations (as we currently understand them) associated with long distance space travel. In the message I tactfully challenged anyone in the know (a physicist, for example) to discredit my basic premise that speed alone will not suffice to permit interstellar exploration. Sadly, no one has responded. I could infer from this that, despite insignificant technical flaws unrelated to the basic premise, my argument is reasonably valid. I say this not to prove a point in this forum, but rather, to validate to some degree my thoughts so that I be not the fool in forwarding them to those who hold the …

When you look at any Solid object at a molecular level all the molecules are tightly packed together moving fractionally in all directions, but in a Liquid and Gas the molecules are widely spread apart more so in the Gas which allows us to travel through water and oxygen. If you could construct a wall with the molecules are spaced evenly apart this would allow it to be walk through and to make it solid a freezing chemical can be used to stop the molecules on the spot instanty causing the wall to become solid. This may just be a load of old **** but its been on my mind eversince my girlfriend moved in next door and we wanted to get rid of the joining wall but counldnt …

Hello. My name is David Stebbins. I'm a 17-year-old student in high school who wants to go into nuclear physics as a career. I could have sworn that I joined here before, but my account was obviously deleted because of inactivity. Anybody remember me? Anyway, do you know of any schools that I could go to? I graduate in 2007. I'd like to go to an Ivy League college if I can find one that will accept me for an affordable price (I may go into the US Army to get aid). I think I have the intelligence to make it in an Ivy League college. I'm passing Algebra 2 with so much ease right now that I can get all my homework done in class, much less on the bus, and I never …

molecular thermodynamics is the study of how molecular motion disturbs or reduce the efficiency of heat transfer through bodies (eg hotter to cooler bodies). It is a branch of Thermodynamics. The theory of temperature which is the bed rock of this study states that the faster you go , the cooler you become and the less you age and the more you are behind time. this makes it difficult for a moving car or molecule in a gas to get heated easily this is called the theory of energy efficiency, it states that: "the reason why heat energy cant be successfully transferred from a hotter body to a cooler body ,100% effieciently is because the molecules in the both body …

Hi everybody! I am doing some research in physics which also involves chemistry. The research is primarily based on physical science principles, but sometimes chemical knowledge is also required. But unfortunately, I've not took and chemistry courses just yet and don't think I'll be taking any till next year. So, do you guys know about any website, book, or any other learning material that would teach the involvement of chemistry in physics? Right now, I only have a few amount of time to learn the fundamentals of chemistry that involve physics. I don't think I'd be studying chemistry itself, as I don't have enough time. So, please be specific. Thanks.

Every time a gymnast flips, charwheels and somersaults, she has rotational inertia. Now say the gymnast does not have any/zero rotational inertia, how wel would the gymnast perform and how fast would she be able to change her angular velocity (angular speed and direction)? How many times would the gymnast be able to change direction while flipping and turning? P.S.: I know what moment of inertia is; I am just using rotational inertia to use as a property of moment of inertia, like linear inertia is a property of mass.

http://physorg.com/news10336.html

The concept of realtive space and timedid not originate with Albert Einstein. It had been stated already twice, in different forms, during the nineteenth century by Bernhard Reimann and by Ernst Mach. The speed of light had alredy been calculated by james maxwell and independently measured. The principle of relativity had been clearly stated and applied for many centuries, altough no to optics. Einstein's invaluable contribution, while the rest of the scientific community was pre-occupies with the ather, was to tie these ideas together with the notion that the speed of light was constant for all observers, and to show this resulted in an entirely new way to view the unive…

I want to create a circuit that dims or brightens a LED. I want the LED to glow BRIGHTLY as the environment around it gets darker, and vice versa. I know I have to use a photovoltaic cell and maybe transistors, but the exact wiring of this circuit escapes me. I will probably also use a separate power source for the LED, but maybe not. Help please!

basically wtf is it? it has a mass, but not a charge.. usually masses without charges have an equal # of protons and electrons... but a neutron is a neutron.... ie what will happen if you bring an electron close a neutron? also.. protons and electron exhibit particle-wave duality, does the same apply to a neutron?

Let's do away with particle/wave duality!!! See attachement Investigating_3.doc

I have been trying to learn college-level electrostatics at home. I've understood charges, electric fields, and voltage, but haven't quite grasped Gauss' law and some of the capacitance theorems that base off of it. Every site I have gone to seems to explain Gauss' law in a tricky, vector-related form. Since I only have a basic understanding of vectors, I can't completely understand how the formulas and calculations work. Not to mention my confusion with the various symbols in the equations. Is there anyone who can simply explain the law and any necessary prerequisites to understanding it? Any help you can provide will be valuable in my pursuit of knowledge. …