Physics

Neat summary that was just emailed to me. Drop a marble onto a bed of fine sand and you get a fluid-like response, but there's no cohesion or surface tension as in a fluid. Also, you get jets of sand from the interactions in the impact void whose behavior depends on the ambient pressure. http://jfi.uchicago.edu/~jaeger/group/granular2/jets.html

My physics absolutely stinks, mostly when it comes to the absolute basics. So anyways, there was this guy who survived a 47 story fall, onto the PAVEMENT. Splat. When someone/something is falling, do they keep accelerating as they fall further and further, or do they reach a maximum speed? Does someone who falls 90 stories have similar chances of surviving to someone who falls 47 stories? I've read about people surviving falls out of airplanes, so something tells me that I am right, but I am not sure. They had to pump almost twice his normal blood volume back into him. What a mess. http://news.yahoo.com/s/ap/20080104/ap_on_he_me/skyscraper_fall_survivor

http://sohowww.nascom.nasa.gov/descriptions/mission/soho_solar_maximum_proposal.pdf This is a concise, though reasonably in depth amalgamation of what the satelite has shown us. In an earlier post I mentioned about a second "solid" layer beneath the photosphere. This was first based around a NASA channel broadcast in 2006 that showed how, when using a vignette, the inner layer can be seen with the bombardment sensors. I also found a blurb on the SOHO site later that year that described the same, but it's eluding me, as irony would have it. The broadcast was fascinating. No what I layed claim to has nothing to do with iron content, but with comparisons to the gas gia…

Hey I am making a boomilever for a science project. Does anyone know how to either a.) construct it- there is like no site that tells you how to do it b.) construct joints so that it makes the boomilever stronger Answers to both questions would be great. Links to sites would be great or just general info. Thanks again

If a boat is moving with constant speed through the water are there any drag forces acting on it?

okayy well i think i have an answer..but i dont know scientific reasoning.. heres the problem: Consider drops of water that leak from a dripping faucet. As the drops fall they a)get closer b)remain at a relatively fixed distance from the other c)get further apart i said "c"..but now i need scientific reasoning.. how do you put scientific reasoning to that??

Hi guys, I came across an interesting problem recently while building a water feature out of an old kettle and a terracotta tub. I mounted the kettle at a 45 degree angle on a piece of pipe and had this feeding into the tub as per my rough drawing at: http://erickendall.gallery.netspace.net.au/water-feature The return pipe to the resevior gave me the water level in the tub, but to make the whole unit look better and to stop leaves and debris going down the return, I made up a brass cap so the water would have to be drawn from below the water surface to get to the return. I thought this would work quite well, but after about 2 minutes of running the unit, it made a gurgl…

Take a look at this image, produced by me in Photoshop: I began with the two lower circles. The are red (left) and yellow (right) at 50% opacity. At their intersection, they produce orange. Then I took another circle and placed it overtop (purple) again at 50% opacity to produced red (well, kinda pink - considering the opacity) at the intersection of it and the previous intersection. Now my question is this: how does one explain the re-emergence of red (or pink?) when red was used to begin with. That is, if we go with the theory that red is one of the primary colors (so it is fundamental), then it shouldn't be possible to re-create it as a composite of other …

Does the underwater hot spouts have something to do with currents

I'm struggling with understanding the Einstein Summation Convention with respect to Lorentz transformations. Is anybody able to point me in the direction of some easy to read resources on the subject? Thanks in advance!

If I wanted to open the jar of jam but the lid was too tightly capped I would pour very hot water on the metal lid, and I could open it easily, why does it work? If the lid is made of plastic, would pouring very hot water on this plastic lid work just as well, ? why is it so?

If I stirred the water in the beaker vigorously for 3 minutes, will the temperature of the water increases, decreases or stay constant?

Does decoherence use environment in wave functions to produce point values? I am reading up on this subject currently and from the basis of einselection I guess is the mechanism that leads to the classical world or such phenomena. The of course you have the field of complex systems I think trying to describe emergent behavior. What I don’t understand about the emergent behavior aspect is that what has emerged is to be somewhat a discrete unit to itself. Such as in the wiki article on emergent systems and or behavior, don’t recall exactly, psychology was worded as to be separate of biology(to be honest that sounds insane to me). In string theory a primordial “on…

Slightly random question but anyway..... As a keen shisha pipe collector I spend a lot of my evenings practicing blowing smoke rings while I watch tv. Recently I've been wondering whether it would be possible to create other shapes i.e. stars or triangles and experimented with making hollow shaped tubes to see if I could make any. As expected it didn't really work. Why is this? Is there a reason why rings seem so stable or are other shapes possible? What do you think?

I never really like when time is explained as the fourth dimention. Let me tell you why. Whenever higher dimensions are explained the comparison of 3D to 2D is included where they push a sphere through a 2D plane and a circle appears, grows, shrinks, then disappears on the plane. I don't like the idea of time being the fourth dimention because we never see anything pop out of nowhere grow, shrink, then disappear. Comments please.

Do you know of any physics discoveries or developments this year that you'd propose for a "2007 top ten" list? Here is Physics News Update's list: http://www.aip.org/pnu/2007/split/850-1.html?source=rsspnu PNU is the newsletter of the American Institute of Physics. I think their list is usually pretty good, but they may have left off some goodies this year. I'm thinking of one in particular (watching a wave function collapse), but don't know where the link to it is. Here's something: http://www.nature.com/nature/journal/v448/n7156/abs/nature06057.html;jsessionid=84F7B86DFA0F1C9134787348DDF92F22

Recently I've been trying to understand how ocean currents work from a general perspective. While studying, an intrigueing question popped up in my mind, and I haven't been able to let it go unanswered. It is simply: If the Earth was a completely smooth, ocean covered sphere (but otherwise unchanged), how would the ocean currents flow? I think that answering this Q might help one to understand what makes all the world's real ocean currents tick. Any suggestion? Cheers, Michael

When viewing spacetime in relativity if I understand correctly light or photons give rise to the ability to see the warping of spacetime along with other bodies such as planets right? If that is true could you look at the fabric as a wavefunction that is distorting? I mean does any merit for that thought exist in either math or the real world?

Hey guys, I have a question that's been bothering me lately and I'm hoping someone can give me the scientific explanation. Everything is made up of atoms.. myself, the table in front of me, etc.. correct? And atoms are pretty much just empty space right? (I seem to remember an analogy along the lines of "if the nucleus is a basketball in New York, then the electron would be a golf ball in London".. or something to that effect). So it stands to reason that my body and everything around me is pretty much entirely empty space right? If this is the case, how is it that I can see and feel these objects? What am I seeing and feeling? Thanks so much in advance.

What does it take? To level an upper middle class home with brick walls and a quality foundation? To knock a building down with steel frame? To drag 2-3 ton cars around? To flip an 18-wheeler over? I live in the south suburbs of Chicago. We get tornadoes here frequently enough. Every year at least one tornado (that is spotted) touches down in our county. One of the worst tornadoes ever happened right here not 3 miles east: http://en.wikipedia.org/wiki/Plainfield_Tornado#Tornado_touchdown.2C_path.2C_and_damage I live in an upper class housing development. A couple years back when the development was still being finished on the other side we ha…

Hi all, I'm looking for some input on an experimental setup. I need to create a hot zone of about 800 centigrade and move a 2x2 inch bronze base through the hot zone. Ideally, the bronze base needs to be in a ambient temperature zone, then as soon as it hits the hot zone it heats up to the 800 or so centigrade. I initially thought of using a beam of light with a lens. I was thinking about using a 1000W halogen spotlight (8 inch diameter) and then use a lens to focus the light (the hot zone can be pretty small). Does anyone know any relationships of energy (temp) with respect to focal distance and diameter of lens? I was hoping to find a lens that would work fo…

Does nucleation lead to any product larger then monoatomic in state? Such as nucleation is required for planetary formation even? Stars if I am correct have to have a certain mass to go nuclear right? So if a star is roughly homogenous would it be something in the order of buckyball on steroids or astronomical units of measurement, Or at certain masses would other natural phenomena start to take over such as atmospheric patterns due to the motion of say energy and matter within the system? I am just wondering if nucleation is sort of a seed state that can lead to a certain types of phenomena from molecular in scale to how large or what is the cut off on the effect of…

Hello, hi, bonjour etc. to all! I only reckon that I may how come up with a way to produce energy with no combustion fuel which makes its pollution FREE!! I know what your thinking...what planets is this guy on etc. cause it already exists right?? i.e solar power, wind turbines, tidal, hydro and wave. the thing is with the above they have flaws .... solar:- dont work well on cloudy days and cant produce enough juice. wind:- noisy ugly things that only work in certain places, ruins tv reception and only produce the goods when windy of course tidal:- extremely expensive and only works in certain places but does produce loadsa power hydro:- ok bu…

How do you create a constant static charge to a rubber conveyor belt?

The Float Serve I am a volleyball player and also currently taking Physics in my last year of high school. I am trying to explain the odd trajectory that a volleyball follows when it is served a certain way. The Main Idea: A float serve is implemented in the game of volleyball to make it as difficult as possible for the opposing team to effectively receive and play the ball. By contacting the center of the ball with a hard hand and not following through with the swinging arm, the ball follows a very odd trajectory through the air, making it appear as if it were floating through the air (traveling side to side, up and down, and curving) WITHOUT any kind of s…