Cause Definition and 563 Threads

Hello Forum, it can happen that in a VoIP conversation we hear some echo, i.e. we hear our voice, with a certain delay... We speak and the signal goes to the receiving party. Why would a copy of our voice signal make a round trip and come back to us? What causes that "reflection" of the...

Hi everybody, some time ago our teacher has shown us the following example from the theory of elasticity: Calculate how the gravity of the sphere changes its size. The sphere is made of ideal linear material (in practice, perhaps some metal) with Young modulus E and Poisson ration \nu. The...

Due to diamagnetism in certain substances such as water, does this cause a faster orbital spin due to the change in magnetic dipole moment induced by an external magnet? I'm doing a Science-fair project at the moment and this is eluding me Thank you

So I'm designing an impeller and rather than how to prevent cavitation, I'd like to know how to cause cavitation. I've read up on fluid shear stress and Couette flow, but this all appears to be based on relative velocity dV, of parallel discs, separated by a small distance dX, and fluid of...

When you move your hand with a slinky in it, the slinky begins to move because you gave energy from your hand to the slinky. A wave is not always formed, but when the disturbance from your hand is rhythmic, a wave will form. Is this right so far? A force acted on the slinky and caused a...

Now it's known that waves can't cause the displacement of an object but i made a few experiments that proves it can. For example , wind can cause a wave the can move a piece of paper. However, a water wave can't cause the displacement of and object but other waves like wind can cause that waves...

In principle, what is the absolute simplest arrangement to cause decoherence? In other words what constitutes a measurement? Clearly gravitational interaction is not sufficient.

As the tittle, can varying magnetic field ( well EM) cause eddy current in non magnetic conductors like aluminum? If so, why? Thanks Alan

America made a lot of enemies so they need a powerful military -or- America has a powerful military so they made a lot of enemies?

So far as I understand it, mass/energy causes gravity, and gravity results in time dilation. Does anyone know of a theory that views mass/energy as causing time dilation, and the differences in time are what causes gravity?

If i have a shaft & I'm applying a driving torque D at one end & at other end there is resisting torque R due to bearing friction, etc. Then if D>R, i have net torque = moment of inertia times angular acceleration. Since the ang. accln is constant with respect to time, will the ang. speed of...

I know physical bodies with mass cause gravitation. But do massless particles, like photons, also cause gravitation ? I know they're affected by gravity, but would a cloud of photons bend space by itself? Thank you

Hi, I live in 6th floor of an apartment. To prevent birds from pooping beside my window, I hang some unlabeled CDs along a string outside the window. The window is facing east, and people start complaining about it, that it might cause fire. I wonder if that is even possible? I personally do...

Homework Statement There are two beads at the top of a hoop that is tied by a string. The beads start moving downward on the hoop on each side. M is the hoop's mass and m represents each bead's mass. What is that mass ratio that will cause the hoop to elevate.Homework Equations T>= (M...

If I have a string with a lump on the end and is being swung in a circle with a continuous angular velocity then I know that: F= m\frac{v^2}{r} or using angular velocity, F= m r \omega^2 But, is there a tangential force acting at the point of mass in its instantaneous direction, and if...

what is the cause of upthrust experienced by a body placed in a liquid.

if you have a pendulum with a 10kg bob at rest, it causes a stretch in the wire supporting it, but if that same bob were to be let go at a certain angle from the vertical, would would the wire stretch more as the bob reaches the bottom of its swing where the speed is the greatest? in order...

I have read a few posts and threads in here regarding the orgin of the Univers and also the big bang (BB). Some of the posts seemed to get a little heated. I am merley looking for clarification and honest dialog and input. First off I am a philosopher and I follow science so I tend to...

Since it's been observed that mass causes the curvature of the spacetime continuum. I'm wondering how it curves the spacetime continuum at a distance. For example, a planet will curve the spacetime around it millions of miles away, yet all around the planet is the almost perfect vacuum of...

I don't understand where radioactive decay comes from. Everything I've read discusses how the environment can influence the decay (for example, neutrons in different nuclei decay with different speeds), but I couldn't find an explanation of what is the underlying cause of the decay. If the...

Utter conjecture;- We see superclusters forming mass filaments along the 'edges' of poincare-like manifolds. The seemingly dodecahedral structures present in our universe may have been created on the edges of simple geometric 'kissing' surfaces (sphere packing) where the edges would represent...

Could too much pressure cause liquid inside of a film container ( There is a sheet of film, which is formed into a packet, the liquid is then put inside the packet, then the film is sealed) to slice through like a knife or some sort of sharp object had been used to cut it? If so, about how much...

Acceleration doesn't "cause" the Twin Paradox? In a recent review of a physics textbook, the reviewer is critical of the author of the book because the the author doesn't correct the persistent notion of many students that it is the acceleration of one of the twins that "causes"[reviewer's...

I think that buoyancy is caused by the increase of density with depth (the deeper you go, the more molecules there are per unit volume). Therefore an object in a fluid will be hit by more of the fluid molecules from below than from above (even if the difference is only a tiny fraction of 1%). Is...

Hello All, It is said that Earth has an envelope of gases (air) surrounding it and that due to gravity the weight of this envelope of air exerts a force: on the surface of Earth and any thing on it. The weight of air column on any surface divided by the area of the surface is...

Do waves (all types of waves) cause heat (however minimal) when intercepted?

What is the cause for diamagnetism and other types of magnetism? Is it related to Farady's law or quantum mechanical properties of matter?

Hi all, i am beginner in fortran and linux. I have wrote codes for 1d scalar wave as below: SUBROUTINE fd1d (x_num,x1,x2,t_num,t1,t2,c,u_x1,u_x2,u_t1,ut_t1,u) implicit none integer (kind=2) t_num,x_num,t,x real (kind=4)...

It may superficially sound like a stupid question with a simple answer, but let me explain in more depth. Calories are units of energy, as you probably know, and grams are the the weight of the food. So calories are not directly related to the weight of a food. Foods range in the amount of...

Could two Inflationary universes bumping up against one another result in the anisotropy seen in the Cosmic background radiation and thus ultimately lead to galaxy formation? And could the signature for such an event be measured? It seems two "big bang" universes arising near one another might...

I'm going to see a GP in a few days but in the meantime I want to get an idea of what could be causing this worrying symptom. This has happened 3 times so far, I'm sitting on the bus and pins and needles slowly start developing in my face. It is very gradual, I feel it building up for at least...

According to Misconceptions about the Big Bang in Scientific American by Charles H. Lineweaver and Tamara M. Davis, space-time is expanding and carrying galaxies with it, rather than galaxies being moved ever faster and further into space-time. See...

http://en.wikipedia.org/wiki/Gyro_Monorail#Principles_of_operation It appears that counter-rotating gyros can indeed provide stability without precession. Is this simply because of the fact that when you accelerate the rotation of the axis of adjacent counter-rotating spinning wheels you are...

I am taking AP physics and have taken physics before but am puzzled. I started thinking about the classical tug of war question. I get that a team wins in tug of war not because the pull on each other but because they push on the ground. This is b/c of Newton's 3rd and b/c there is a net force...

Newtonian physics correctly predicts that a planetary orbit will be an ellipse and general relativity correctly predicts that this ellipse will rotate, as was demonstrated with mercury. The only thing that I can think of is that because the orbit is an ellipse then the planet will be...

If the universe was smaller than a proton before the big bang, can we say that the question of the cause of bigbang is meaningless (i.e. it happened without any logic)? I say this because sub atomic particles keep on popping in and popping out of existence without any underlying cause. Or is...

I really can't understand how faster than light travel creates the cause and effect paradox. I have spent many days on internet searching this specific problem but not able to get it. Can some one explain it to me in the easiest way. Another question : i have read many times that...

Lactose has a huge insulinemic index for its glycemic index.* Since insulin lowers blood sugar and the glycemic index is a measurement of how fast a glycemic load raises blood sugar, could lactose cause hypoglycemia? *http://www.ajcn.org/content/74/1/96.full

What causes momentum? Are there some force carrier particles passed on from one object to another causing momentum?

Hi, I would like to ask you, if you consider NaClO2 harmless for the human body/cells. I am asking because my father want to try the "healing" method described by Jim Humble but I am afraid he can make something bad to his body. I am not good in chemistry, so, I would like to ask you...

Is the reason behind the vibrating the movement of electrons from a stable to a excited state? My quest for knowledge began with this question..."How exactly does light transform into heat--for instance, when sunlight warms up a brick wall? I understand that electrons in the atoms in the wall...

Some textbooks that I read explain it in a way kind of like this: In a material the photons is absorbed by an atom and then re-emitted a short time later, it then travels at a short distance to the next atom and get absorbed&emitted again and so on. How quickly the atoms in a material can...

Me and my Dad were having a conversation about the elongation of EMR wavelengths over an extended period of time. He began to explain to me what Red Shift was but I couldn't understand what he was trying to get at (he's a poor explainer, or I'm bad listener). But his explanation did spark an...

Homework Statement Because there is no such thing as absolute simultaneity, two observers in relative motion may disagree on which of two events A and B occurred first. Suppose, however, that an observer in reference frame S measures that event A occurred first and caused event B. For example...

Hi! I had a thought as to how leptons hold the properties attributed to them by Heisenberg and modern quantum mechanics. It is my belief that the Uncertainty principle is caused only by the fact that the fast moving electrons distort space and time in their local fields. This may be accounted...

The books say that interference happens basically between the light waves from the two mirrors. But it seems to me that the path difference between the pairs remains constant for all the waves (as long as both the mirrors are perpendicular to each other). So why do circular rings form? How does...

I don't understand how a handful of single wavelength absorptions could be enough to profoundly alter the colour of the compound. Since the visible light spectrum is continuous doesn't it contain billions of single wavelengths? For example copper atoms in solution appear blue because it absorbs...

Homework Statement What is the cause for the bump in the lower energies of this spectrum: http://en.wikipedia.org/wiki/File:Gammaspektrum_Uranerz.jpg The Attempt at a Solution Is it just normal Compton? I'm doubting that because that is very asymmetric. I can't find anything in any textbook I...

Regarding the thread St. Thomas Aquinas and "uncaused first causes", it appears the author is restricting causation to mean only an ordering of events into a "before" and "after," what Q_Goest perhaps means by saying that "the reductionist concept of cause and effect [...] may or may not be a...

Light normally doesn't interfere with itself because it is incoherent and unpolarized, right? So how is it that incoherent, unpolarized light passes through a circular aperture and interferes with itself? How does the aperture suddenly cause the light to be able to interfere with itself? In...