Cloud Definition and 256 Threads

  1. Russ Edmonds

    My expansion cloud chamber movie

    Hi all, below is a video showing a compilation of many expansions of my Wilson cloud chamber. The tracks shown are mostly alpha and cosmic rays. The chamber uses a rubber bulb from a turkey baster as the expansion piston. The object in the chamber is a cork with a radium paint coated pin. I'm...
  2. C

    Modeling Thunderclouds with Point Charges and Conducting Planes

    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...
  3. N

    Inside radius of atomic electron cloud vs Z

    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?
  4. C

    How Long Does It Take for a Collapsing Interstellar Cloud to Heat Up by 800K?

    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...
  5. mishima

    Can Cloud Cover Be Predicted at Night Using Simple Daytime Instruments?

    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...
  6. B0b-A

    What has caused this panda-face in a cloud chamber ?

    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...
  7. Saitama

    The Temperature Profile of a Spherical Cloud of Ideal Gas

    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...
  8. B

    Atomic Hydrogen gas cloud to Star

    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...
  9. rkum99

    Ionizing Radiation in a Cloud Chamber

    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...
  10. S

    Identifying trails in a 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...
  11. M

    Can a Cloud Containing 8 Solar Masses Collapse?

    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...
  12. M

    Is the Cloud of Hydrogen Gas Likely to Collapse?

    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...
  13. C

    Does an Orgonite Cloud Buster Really Improve Weather in Africa?

    Bust Clouds in Africa for just $595... http://www.orgoniseafrica.com/cloudbuster-for-africa.html Explanation here.. http://www.orgoniseafrica.com/orgonite-cloud-buster-28mm-resin-metal-artwork.html There are even reviews by customers...
  14. T

    Cloud Chamber Solvents: Identifying Mystery Liquid

    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...
  15. J

    What would happen if a big superfluid cloud eclipses the Sun?

    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...
  16. T

    Why Isn't My Cloud Chamber Showing Tracks?

    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...
  17. T

    Can Cloud Chambers Help Demystify Nuclear Power?

    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?
  18. F

    Cloud Chamber Using Peltier Coolers

    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...
  19. S

    Could a universal Oort cloud structure cause expansive acceleration?

    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...
  20. G

    Enclosed charge of an electron cloud with a given charge density function.

    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...
  21. L

    How Does a Magical Cloud Factory Create Supercells?

    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...
  22. B

    Meteorology question: Cloud direction vs wind direction?

    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...
  23. M

    Adiabatic Process: Burst Tire & Cloud Formation

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

    A spacecraft encounters a stationary dust cloud of density rho.

    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...
  25. C

    Preventing recombination in a diffusion cloud chamber?

    Hello all, I built an expansion cloud chamber and noted that an electrostatic field was needed to see the ionizing radiation. I know this is needed to prevent recombination of the ions and their free electrons. However, I built a diffusion cloud chamber a while ago that called for no electric...
  26. C

    How do electrostatic feilds impact cloud chambers?

    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...
  27. M

    Electron Cloud described by a Gaussian distribution

    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...
  28. R

    Calculating temperature of Hydrogen gas cloud

    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...
  29. A

    The change of mass with respect to time of a rain drop falling though a cloud

    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...
  30. M

    Red circular cloud seen at 3:00 am far from town and black sky all around

    I was out walking my dogs at 3:00 a.m. (that i might let them off the leash to be dogs for awhile) Over my head was a strange red cloud, circular and occupying about 2/3rds of the sky overhead, white faint whisps around its perimeter, as i got farther from the light pollution of town the...
  31. wukunlin

    What Causes Holes in the Sky Over Tainan, Taiwan?

    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]
  32. L

    What Causes Unusual Cloud to Cloud Lightning?

    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...
  33. T

    Cloud Chamber Building for 9th Grader: Dry Ice vs. Peltier Cooler

    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...
  34. DaveC426913

    Dancing Cloud Phenomenon on YouTube - Bad Astronomy

    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...
  35. J

    Oort Cloud Dynamics: Speculations on Origins in a Sci-Fi Novel

    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...
  36. C

    Physics of a Cloud Chamber: Neutrons, Kinetic Energy, and Ionization

    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...
  37. A

    Cloud movement, finding temperature, velocity and height from this formula

    1. An unsaturated parcel of air is entrained into a cloud near the region of the cloud top. the updraft velocity U, the ambient lapse rate in ther cloud γ, the entrainment rate E, and the mixing ratio of the condensed water μcan be considered constants along the trajectory of the parcel...
  38. A

    Calculating Degenerate Remnants and Main Sequence Lifetime for a Cloud Collapse

    Homework Statement 1. Consider a cloud that consists entirely of molecular hydrogen. The temperature is a uniform 15 K and the number density of particles is 5x109 m-3. Assuming a 100% efficient collapse, subsequent star birth and normal evolution, what type of degenerate remnant will result...
  39. C

    Is the Oort Cloud Large Enough to Encompass a Multi-Stellar System?

    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...
  40. Orion1

    P2P cloud computing GPU simulation

    https://www.youtube.com/watch?v=5qyhLAsVxlU I have been considering a concept that is beyond my technical qualifications. I want to start development of a software project that is based upon some convergent concepts, and I am requesting collaboration in writing a scientific paper on the...
  41. B

    Clarification between electron cloud and a wave

    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...
  42. G

    Is Cloud Computing Right for Me? A Skeptic's Guide

    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...
  43. M

    How do collisions affect the evolution of objects in the Oort cloud?

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

    Velocity of light in water cloud

    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?
  45. Loren Booda

    When will we be able to image the Oort cloud?

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

    How Does Electron Charge Density Affect Electric Field in a Hydrogen Atom?

    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 +...
  47. Vorde

    Molecular Cloud Clumping Question

    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...
  48. B

    Galactic angular velocity of interstellar cloud

    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.
  49. S

    Amount of isopropyl in a given cloud chamber

    EDIT: The title of thread is misleading. Instead it should say: "Aquarium cloud chamber - realistic?" Hello, I am currently constructing a cloud chamber which is going to be using a w% > 90 % solution of isopropyl alcohol as the condensation chemical. I am using a typical home aquarium with...
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