Classical Physics

Dear All, I have a question involving a perfume bottle with a wick to 'disperse' the smell to the atmosphere. Please see the attached diagramme. What is the minimum gap 'd' so that the perfume will still be taken-up by the wick (due to the atmospheric pressure) so that people can smell the same level of perfume? The gap must be small enough so that when the bottle is inverted, the perfume won't leak through the hole. I tried to think back to my physics lessons but nothing useful came up...... 'd' has to be larger than a nitrogen molecule for it to pass through but how large it must be in order the wick to work normally and to prevent leakages when the bott…

Hey. I`m going to do an experiment to se if the magnetic field around a magnet changes when the temperature of the magnet changes. According to Currie´s law, M = C x ( B / T ), the magnetization of a material is inversely proportional to the temperature. If I have understood this right this means that f.ex. a iron nail in a magnetic field will be less magnetized if the temperature of the nail is higher. This equation does not speak of the temperature of the magnet which is making the magnetic field. My question is: can i use the same equation to determine how the magnetic field around a permanent magnet will change as a function of the magnet´s temperature…

Hello, I am very much interested to how frequency of sound varies in water. Also, how the frequency varies with temperature and depth? What are the different formulas related to this? Secondly, how can we determine the best frequency of operation? I would be very thankful if anyone could answer the above questions or point to materials explaining the above. With regards

As a discaimer, I realize that this theoratical device is both highly inefficient and is an engineering nightmare, still, I'm curious as to whether - it could, theoratically, work as intended, and if so, - is there anything like it in existence/has it been tried. Please exuse my english. From what I know (Which is not much, hence why I came here to discuss this), gases on a molecular level behave like small ping-pong balls, bouncing around all the time: http://lab.concord.org/embeddable.html#interactives/sam/phase-change/2-two-types-of-gases.json On large scale, the force inflicted on a sufrace by gas (In a peaceful environment) is more or less constant (the…

This maybe something or not, since my apparatus maybe too imprecisely setup, I was freespinning the front wheel on my new bike and noticed that, no matter which way the wheel started spinning, once it came to nearly rest it always turned a fraction the other way before stopping completely. Where does this slight reversing 'force' come from? It's almost like a recoil.

You drive on the highway on a very long straight line. In the mirror, you look at a fast car coming closer and closer. Then the car comes really close and passes you by. Zouf. Then gently goes in front of you, getting smaller and smaller, slowly vanishing to the horizon. Don't you get the impression that the car was going faster when it was close to you? Maybe not because you have seen this effect so many times that it means nothing to you. The picture below. The real distance between the light posts is equal. Because of the effect of perspective, the apparent distance beween the posts (the colored lines on the picture) gets small and smaller until z…

I'm just having a mental block how to understand this real simple diagram. http://www.physics.usu.edu/Wheeler/GenRel2013/Notes/GravitationalWaves.pdf So it looks like an oblique view of a binary orbiting system. There is an observer O at r1 and r2 from the bodies. Gravity propagates from the bodies to the observer at the speed of light c. Since gravity takes a different length of time to reach O does he feel the pull of gravity as is drawn? I'm thinking the pull of gravity from the shorter arm will arrive earlier than the longer side. OK that is as far as I got, but what position are the bodies at so that the gravity arrives at O at the same time? I c…

I know light paths are bent in a gravitational field but I haven't heard of light being attracted to light. What is the smallest mass proven/known to fall in a G field? Is it the electron? Gas molecules combined mass produce atmospheric pressure so even atoms as small as Hydrogen fall due to gravity. So masses smaller than Hydrogen only need to be considered. This report talks of gravity effect on neutrons: http://www.nature.com/news/bouncing-neutrons-probe-dark-energy-on-a-table-top-1.15062 .

When we see the astronauts clips in the ISS or the old Shuttle, we think that they are floating because there is no gravity. In factthe gravity in those orbits is almost the same as here on earth. So what keeps them floating is a never ending freefall. That's what I was reading, but I am having problem to understand it well. As I see it the ISS or the Shuttle, is not freefalling, but is just moving damn fast, so fast that it can escape the gravity pull. A freefall example to me would imply that you are falling towards the centre of the earth, and not east or west. When we are dropped from a tower, sitting on a chair, or inside an elevator, we would experience a weghtless …

I was reading a wikipedia article (https://en.wikipedia.org/wiki/Gravity_of_Earth) that said that gravity at the equator is weaker then gravity at the poles for a few reasons. First off the poles are flatter than the rest of the planet, meaning you're closer to the center of the earth, hence more gravity. The reason that they are flatter is because the earth is spinning, and the centrifugal force (if your into puzzle boxes: http://www.yot.com/ it involves centrifugal force) is making the equator bulge out. This bulge leads to our next reason the gravity is weaker. SInce you are farther from the center of gravity the gravity is weaker there, and since the planet is spinnin…

Ok, while reading about the curvature about space time, black holes, and gravity, I came across a formula that tells you how small something has to be to become a black hole. Since a black hole has a huge amount of gravity at the event horizon, I came to the conclusion that perhaps gravity changes as density increases. The formula is as follows: R=(2GM)/(c^2) This means that you can calculate how small something has to be to become a black hole by "doubling the object's mass, multiplying it by the universal gravitational constant, and dividing the entire thing by the speed of light squared" This is a quote from the website http://io9.gizmodo.com/5974372/at-what-point-w…

I watched a science documentary that suggested that "gravity may be an illusion" and argued a case that entropy could be a possible cause of what we consider is gravity and effect of gravity could be a cause rather than a fundamental law as suggested by Newton. In the argument are some good cases were put forward such as LIGO has been looking for a gravity wave for ten years and has not found one (apparently it has discovered the chirping of crickets). It made me think. Let's suggest there is no such thing as gravity. Now consider that space has many of the properties of liquid. It transmits waves, light etc. It is expanding and hence flexible and according to Einstei…

I propose the following challenge: let's build a fortress. Would it be possible to create a wall using the laws of nature so as to make "breaking it" not even an option? I'd guess it'd be a safe bet on kickstarter for a nice price: one million for anyone who proves is is not possible - or for an idea to make it possible. Would be interesting to find out what's on the other side of that wall, once its cut off from the universe ;-) Kind regards, Thomas

what would happen to entangled particles as a gravity wave passes through one of the particles and not the other? Would this place a stress on the entanglement phenomena with a weak wave, and with a strong wave disrupt it totally? and what would happen to two entangled particles that eventually get separated past their "light cone" distance from each other, through the expansion of space? "

So, as the Titanic sunk, and began it's 15 minute plunge to the ocean floor of the Atlantic, do you suppose the bodies that were trapped in the ship actually exploded due to the extreme pressure? Consider where the Titanic now rests, the pressure is about 6,500 atmospheres. As it sank and the pressure gradually increased, is it possible the bodies ruptured? ~EE

I was playing around with a permanent magnet today and the thought suddenly struck me: There is an energy field here. Surely that must mean that it is using energy to maintain that field. But the field strength of a magnet doesn't decrease, does it? Whence, then, comes the continuous flow of energy that powers the field?

If we have 2 Tanks. Tank 1 is on the hill, and Tank 2 is on the bottom of the hill. They are connected, is it possible that whole water doesnt go to the Tank 2. And can someone explain to me hydraulic grade line, head loss, and energy line.

I was trying to explain an issue on another thread http://www.scienceforums.net/topic/93442-gravitational-waves-discovery-expected/page-3#entry906394 and I wasn't making much progress But on a site I found the effect I was trying to explain:http://www.sparknotes.com/physics/gravitation/orbits/section2.rhtml Now years ago when I had said that the reduction in the potential energy is always split, half goes into additional kinetic energy and the other half is lost as drag, someone called that the "RB Law". I think it was a known fact long before I found it out so does anyone know the proper name for this relationship? The Potential energy gets more negati…

So let's say we have a meteor that's burned up in the upper atmosphere like they normally would. Does that meteor change the overall momentum of the Earth, regardless of how small the change may be? On one hand I'm tempted to think that all the energy goes into heat and viscous deformation of the atmosphere, but on the other hand if we had billions of those burning up every second , this should cause some drag and change momentum of the planet. In that case what would be the mechanism of it?

Suppose you have a watermelon. You gently push the round head of a pin against the watermelon, and nothing happens. Then you turn the pin around and gently push the pointed end against the watermelon, and the pin penetrates the surface of the watermelon. Or how about the blade of a knife penetrating a watermelon relative to the round side of a stick. -How can this be defined relative to a physics standpoint? Objects with less surface area are able to move mass more effectively rather than an object with more surface area, granted they have the same force applied. Essentially, the pin is "moving" mass when it penetrates the skin of the watermelon. …

The magnetic field could distort entropy of substance and change its temperature. Based on this, possible build a kind of virtual demon of Maxwell, which is based on the distortion of entropy of the substance. This distortion of entropy also allow to have virtual locations with different temperature. In case with magnetocaloric effect the different temperature virtual locations is exists when observed object is present in this location. Will this machine work? This example shows machine which utilize the magnetocaloric effect This example contains a electromagnet, a paramagnetic element which connected with piston and cylinder with gas. All system is experiencing a …

What exactly is wrong with gravity pulling two objects together? Isn't it normal for this pulling action to be from center mass to center mass? Isn't a geodesic nothing more than the path both objects have to take because the physics of motion won't allow any other path? Time is always distorted when two, or more compared velocities differ, isn't it? It seems to me that we tend to measure time in a straight line as per our position, yet rarely are we or what we are measuring moving in a straight line. When the earth spins a person at the equator actually does move further through space than a person in New York. Still take 24 hours. It is perfectly normal. It is not …

Gravitational waves have been measured but what are they measuring? Like we have 2 black holes orbiting each other ..... their orbit decays so they unite. That loss of energy required to have this orbital decay is .... Can we say gravity and gravitational waves are the same? Can someone fill in my lack of understanding of this phenomenon and complete those sentences?

Hello fellow scientists! The Microwave Auditory Effect, or Frey effect (1962), was observed during the second world war http://en.wikipedia.org/wiki/Microwave_auditory_effect(prefer Spanish or German) by people working on radars, who noticed that the microwave pulses created in their head the perception of clics. It has been nicely explained by the sudden thermal expansion of the tissues heated by the microwave pulse, with the resulting faint pressure wave being felt by the ultra-sensitive cochlea. Not only are figures said to match, subjects could also "hear" through their cochlea the expansion of tissues not pertaining to them, and subjects with disabled cochleas don…

Is light energy? if so, it cannot be created or destroyed according to the law of conservation of energy, this video seems to say otherwise (look at 0:25-0:30) link removed per rule 2.7