Cloud Definition and 241 Threads

Homework Statement A thunder cloud can be loosely modeled by two point charges -q and q at heights h and d above the Earth's surface with d > h. Model the Earth's surface as a conducting plane at z=0. Sketch the Electric field lines (on a plane perpendicular to the earth). Indicate the...

I am interested in knowing if the inside radius of the inner most part of the electron cloud is a constant versus Z. For example is it always the Bohr radius, or does this inner radius change as a function of Z? What is the experimental evidence?

Homework Statement An interstellar cloud, made up of an ideal gas, collapses with its radius decreasing as $$R = 10^{13} \left(\frac{-t}{216}\right)^{2/3} \text{m}$$ with ##t## measured in years. The time ##t## is taken to be zero at zero radius so that ##t## is always negative. The cloud...

Hi, I was wondering if I would, or would not, be able to predict the cloud cover for a night using a minimum of simple instruments during the day. If so, how and what instruments? Obviously I could just look at a satellite image or something, but I was wondering how I could do it without...

This image was posted on another forum , maybe someone here may be able to shed some light on the origin of the grinning-panda ... The the cloud chamber does not have an applied magnetic field. The radioactive source is Americium 241 [ from smoke detector ? ]. The duration of the camera...

Homework Statement (see attachment 1) Homework Equations The Attempt at a Solution (see attachment 2) As the gas is ideal and there is no gravity, the pressure is same throughout the cloud. In the thin sphere shown, the mass of the gas is ##dm=dV \cdot \rho(r)##. Let ##\mu## be...

Atomic Hydrogen gas cloud to Star! what would be different about stars and their formation if interstellar medium only has atomic gas and nothing else? how would it affect stellar interior and energy production? My guess is that since atomic hydrogen is less massive than molecular...

Hello! I've been doing a lot of research on cloud chambers recently, and I've come up with a quite a few questions on the behavior of certain types of ionizing radiation: 1) For a start, I assume that gamma-rays and X-rays will induce Compton scattering inside the cloud chamber...

I was thinking of making a cloud chamber and have looked at several videos on them. I noticed several different types of trails and was wondering if anyone can identify which particles they belong to i.e. alpha, beta, muon. I'm am particularly interested in Muons and I won't be using any...

Homework Statement A cloud consists of 8 solar masses of hydrogen gas (H2). Its temperature is 20 K and its radius is 0.6 light years. Will it collapse? Homework Equations Mj=3kTR/2Gm 3/2kT<GMm/R The Attempt at a Solution m=2 x 1.67 x 10^-27 G=6.67 x 10^-11 k=1.38 x 10^-23 T=20...

Homework Statement A cloud consists of 8 solar masses of hydrogen gas (H2). Its temperature is 20 K and its radius is 0.6 light years. Will it collapse? Homework Equations jeans mass [b]3. The Attempt at a Solution [/b I've tried to use jeans mass to solve this however I am finding...

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I recently observed a liquid pooling at the bottom of my cloud chamber. It was purple in color and rather odd. It was certainly flammable, which leads me to believe that it was a result of solventing between the supersaturated alcohol and the canned air used for my chamber...

Imagine a big superfluid cloud the size of the Moon, at the same distance of the Moon in front of the Sun. A total eclipse of 7 minutes. What would happen with the light coming from the sun during these 7 minutes? Would we see a "night sun"? Another question. "Estimates of the photon...

I was working on my cloud chamber today, and I ran into two problems: A) It's not working :) To be more specific, I used compressed air to get the bottom extremely cold. The structure itself is a small plastic throw away cup, with a sponge with 91% alcohol stuck to the top. The bottom (the open...

Do cloud chambers have any practical use in daily life? I mean, nowadays you can pretty much go and buy a Geiger counter anywhere, so are cloud chambers useful as anything more than a physics experiment these days?

Hello All! Does anyone have a good design for a Cloud Chamber using Peltier Coolers? I'm wanting to build a chamber that will be able to pick up cosmic rays/background radiation, that will be a bit more professional than a Tupperware container sitting on dry ice. Does anyone have a good design...

Could a universal "Oort cloud" structure cause expansive acceleration? Could there be a giant sphere of invisible non-reactive matter (neutrinos?), left over from the big bang, so massive that it's gravity is pulling galaxies outward? I know the Oort cloud doesn't pull planets outward, but...

I have a conceptual problem. Homework Statement I was given a charge distribution for an electron cloud of a hydrogen atom in the ground state - ignoring the nucleus. Homework Equations charge density: ρ=charge of electron/(pi*Bohr radius^3)*exp(-2r/Bohr radius) The Attempt at a...

Admittedly, this is a rather strange request. I am an author researching my first fantasy novel, and I'm trying to create at least some degree of verisimilitude for regular physics in a world that has powerful magic. One plot point is that a city has created a superweapon in the form of a...

Sometimes, but not always, the wind direction (as given by weather.com for my location) is exactly the opposite of the cloud movement. For example: the wind may be given as NW but the storm clouds are coming out of the SE. Almost always the wind direction given by weather.com is corroborated...

how is the rapid escape of air from a burst tyre and cloud formation in atmosphere an example of adiabatic process? please explain

I'm currently preparing for a prelim and just wondering if my solution to this problem is correct. I did a plot of v(t) and it looked reasonable. You can find the question and solution both at http://oi50.tinypic.com/2e3v4e8.jpg. The Problem states: A spacecraft of mass m_0 and...

Hello all, I just finished building an expansion cloud chamber this weekend and have started experimenting with it. Everything looks solid (vacuum, seal etc) but I'm curious about the role my electrostatic field, generated from a bug zapper and a circuit, plays in visualizing the ionizing...

Homework Statement A cloud of electrons are drifting from a negative plate to a positive plate after being liberated by a laser pulse, (separated by a distance z = 10cm with an original potential difference of 15V) at an instant in time the centre of the cloud has traveled 25mm from the...

Homework Statement The H-alpha line corresponds to a transition between the 2nd and 1st excited states of hydrogen, and has a wavelength of 656.3nm. The ratio of the number of atoms in these two states in an interstellar cloud of atomic hydrogen is 2x10^-6. Find the temperature of the...

Homework Statement A raindrop is falling through a cloud, collecting water as it falls. If the raindrop has mass m and velocity v, show that mg = vdm/dt +mdv/dt. Assume that the drop remains spherical and that the rate of accretion is proportional to the cross-sectional area of the drop...

someone took video of this thing over Tainan in Taiwan, is there any known natural explanation to ummm, holes in the sky? [url]_jEBrT-roJU[/youtube]

Well this is my first thread so I figured I'd start off on the right foot in the crazy forum. In all seriousness I would like to attempt to explain some experiences I've had that I have been unable to find an explanation for. I will provide as much detail as I can recall to try an aid anyone...

Something a recent obsession has taken me into, I'm attempting to build a cloud chamber, for fun and to observe some particles in action. As a 9th grader, I'm somewhat limited in supplies. Thus, I'm wondering, if I built a cloud chamber, would it be better to use dry ice, or use a peltier cooler...

Caught this on Youtube. At first I thought it was a camera aberration, such as a drop of water on the lens. But the effect is independent of camera movement. Anyone know what's going on here? Is this effect something between camera and cloud, or is it really something up at the cloud level? If...

In writing a science fiction novel, I set it against a backdrop of the Oort cloud and, as part of the plot, I needed to speculate on its origins. Recognising my limitations, I would like some expert feedback on my ideas. The first idea I use in my book is that Centaury A & B both developed...

Why can't I have a neutral particle come into a cloud chamber and leave a track? I was reading about cloud chambers and it says when the charged particle comes in it ionizes the vapor in the chamber. But why couldn't a neutron come in and ionize the particles in the chamber with its kinetic...

How far away is the Oort comet cloud? 1000 AU or 10,000 AU? c=10^10 cm/sec. for 10^8 sec/yr., gives 10^18 cm/lyr. Approximately then, is 1000 AU ~ .01 lyr? And 10,000 AU ~ .1 lyr? Would this be large enough to contain a multi-stellar system, since stars form in multiple? Hence a common Oort...

When I've heard and read about the electron "cloud", orbitals where constantly shifting electrons move at breakneck speeds and we cannot model with certainty but only with probabilities of where electrons are likely to be found, I can't help thinking of a wave. It seems to me that it almost...

http://www.physicspost.com/articles.php?articleId=245" I'm really hesitant about jumping on the cloud computing bandwagon. There's something about it that makes me uneasy. Am I being a curmudgeon for wanting to have complete control of my data? FYI: We back up our data twice each day onto...

How frequent are collisions in the ooort cloud? Are there any good reference in the literature about this topic?

If laser energy travels through a non-homogeneous cloud, does the velocity changes with the cloud density as well or only due to the different than air index of refraction?

I find interesting a significant nearby astronomical object whose existence is only inferred.

Homework Statement The electron charge density of a hydrogen atom in its ground state is given by: p(r) = -e/ pi a^3 exp(-2r/a) where a is the Bohr radius Show the E field due to the cloud is given by: E(r) = e/4pi episllon0 ( (exp(-2r/a) -1)/r^2 + 2exp(-2r/a)/ar +...

Molecular Cloud "Clumping" Question I have been told that mysterious 'density waves' hit molecular clouds and that these are what cause these large gas and dust fields to condense into stars and from there planets. What I don't understand is why don't we assume that the clouds own gravity...

I've got a question that I am stumped on right now Show that if the Galactic angular velocity \Omega of an interstellar cloud is > sqrt(4piG\rho/3), the cloud can not collapse in the radial direction. Estimate \Omega and compare it to the rotation rate of the Galaxy.

pros and cons if any?

What exactly is a "radiation cloud", as mentioned currently in the news, in a physics sense? Is it just a bunch of super excited water vapor? Is it actually radioactive isotope particles? How stable is it? I can't seem to find any info on the term.

Hi, I had a previous post "Total Energies" asking about the total energy of an electron and proton separately in a "stable," ground state, hydrogen atom and I got no response (well one short one). Later I realized an isolated hydrogen atom is not stable; it at least needs to bond into H2, but...

Interesting question to think about. We know that there are lots of comet bodies in the Oort cloud and we know that even in the near absolute zero temperatures evaporation does take place. Comets are usually covered in dust, which slows down this evaporation, but let's consider clear body...

What is the largest astronomical body in the Oort cloud? Do such clouds exist for most solar systems?

Homework Statement A star of mass M and radius R is moving with velocity v through cloud of particles of density \rho . If all the particles that collide with the star are trapped by it, show that the mass of the star will increase at a rate \frac{dM}{dt} = \pi \rho v \left(R^2 +...

Homework Statement Beginning with \frac{d^2 r}{dt^2} = -G\frac{M_{r}}{r^2} , adding a centripetal acceleration term, and using conservation of angular momentum, show that the collapse of a cloud will stop in a plane perpendicular to its axis of rotation when the radius reaches r_{f} =...

Note: this is one of the suggested practice problems for my second-year classical mechanics course. Homework Statement A spherical asteroid of mass m_{0} and radius R, initially moving at speed v_{0}, encounters a stationary cloud of dust. As the asteroid moves through the cloud, it collects...