What is Particle: Definition and 1000 Discussions

In the physical sciences, a particle (or corpuscule in older texts) is a small localized object to which can be ascribed several physical or chemical properties such as volume, density or mass. They vary greatly in size or quantity, from subatomic particles like the electron, to microscopic particles like atoms and molecules, to macroscopic particles like powders and other granular materials. Particles can also be used to create scientific models of even larger objects depending on their density, such as humans moving in a crowd or celestial bodies in motion.
The term 'particle' is rather general in meaning, and is refined as needed by various scientific fields. Anything that is composed of particles may be referred to as being particulate. However, the noun 'particulate' is most frequently used to refer to pollutants in the Earth's atmosphere, which are a suspension of unconnected particles, rather than a connected particle aggregation.

View More On Wikipedia.org
Recent contents Top users
  1. T

    Determining ceramic particle sizes suspended in a fluid

    Homework Statement (I) An experiment to determine ceramic particle sizes showed that the rate of descent when suspended in a fluid ranged from 1.2 × 10–6 m s–1 to 5 × 10–6 m s–1. 
The density of the material was 3800 kg m–3 and the density and viscosity of the fluid at room temperature were...
  2. Javier Lopez

    Particle movement in a non-static magnetic field

    Particles follows accordingly the general equation: $$ m*\overrightarrow{a}=q*\overrightarrow{E}+q*\overrightarrow{v}\wedge \overrightarrow{B} $$ But in the case of two coupled coils the time varying current at primary coil (and its magnetic field variation) creates corresponding varying...
  3. Samuel Scarborough

    Physics Navy or Air Force for Particle Physics

    I have been interested in particle physics since I was in High School, but I have struggled to keep my GPA high enough to get me into grad school and I want to serve my country. I decided that the military was the best route to get the experience I needed. I would like to work with lasers to...
  4. Sandeep T S

    I Diffraction experiments with one particle at a time?

    Is anyone did experiment on diffraction with single particle at a time? Do they get diffraction pattern? I referred particle as both electron and photon And I want to know any experiment( classical, or single particle at time) don't show any diffraction pattern in single slit experiment.
  5. D

    If a particle was at position X for zero time, was it there?

    A moving particle has been at position X for zero time. Was it ever at position X? Can zero time be considered as never, as in "I was in Rome for zero amount of time."? It seems like it would have been at position X if time passed in pieces the size of Plank time.
  6. Arman777

    I Event Horizon and Particle Horizon

    The furthest distance that we can see is defined by the Radius of the Particle Horizon which its nearly 46 Gly. However, the cosmic event horizon is nearly 16 Gly. Is this means the galaxies that further than the 16 Gly are just will stay the same in the sky? Since their light can never reach...
  7. A

    I want to build a particle accelerator

    Yes it sounds like I've lost it but I really want to build one. I was wondering is someone could guide me to useful resources. I'm currently reading some patents I found online to gain some more insight. Any help would be appreciated. Thank you.
  8. Zack K

    Location of charged particle given magnitude of position

    Homework Statement A charged particle has an electric field at ##\langle -0.13, 0.14, 0 \rangle## m is ##\langle 6.48\times10^3, -8.64\times10^3, 0 \rangle## N/C. The charged particle is -3nC. Where is the particle located? Homework Equations ##\vec E=\frac 1 {4π\varepsilon_0} \frac q {|\vec...
  9. N

    A Particle swarm optimization for matrix inversion

    Hi everyone, I am working on matrix inversion and focusing on low-complexity method such as iterative method. Recently, I am interested to explore how particle swarm optimization (PSO) can be applied to do matrix inversion. Since I am very very new in PSO, I have no idea how to start my work...
  10. O

    MCNP ignoring particle histories

    Hi, I have been doing some simulation with MCNP. They take a long time. I think there is a way to ignore some particle histories, which reduces the time for simulations. In my model, there is a point neutron source, an object, and a detector. Most of the neutrons do not reach the detector. So...
  11. Davephaelon

    I Particle track resolution of the positive lambda particle

    The positive lambda has a quark composition udc, and a lifespan of 2 x 10 minus 13 seconds. When this particle is created in a collision, inside a modern detector, how long will its track be? At near the speed of light, its lifetime would allow it to traverse less than a tenth of a millimeter...
  12. H

    A Action for a relativistic free particle

    The action for a relativistic point particle is baffling simple, yet I don't really understand why it is written as, $$S = -m\int ds $$ I know it's right because we get the right equations of motion from it, but can one understand it in a more intuitive way?
  13. H

    I Phase and group velocity for a free particle

    Why for the free particle, the group velocity and phase velocity are not the same while we have only one wave? What is the envelope here?
  14. O

    What is the speed of each particle?

    Homework Statement Both m1 and m2 (m1=2m2) masses can slide without friction over parallel and rigid bars that are placed at a distance d from each other. A spring with elastic constant k and with zero natural length connects both masses. The system is placed on a table. The system is released...
  15. K

    Particle Spinning: Why and What Happens If They Stop?

    we all know that particles do spin. But my question is why it does so why do they spin? what will happen if they stop spinning? what makes the particle to do so?
  16. C

    I Why is Proton Radiation this Rare in Nuclear Fission Decay?

    The atomic nuclei consist out electrons, protons and neutrons (with only exception of hydrogen, that does have a neutron). Thus, it would be straightforward, that there existed a corresponding radiation for each nucleus component, when a nucleus decays. There is an electron radiation (beta...
  17. binbagsss

    Multi-Particle QM Homework: Hamiltonian & Vacuum State

    Homework Statement Question attached : Just number 1 please Homework Equations Hamiltonian is given by eq ? In the attachment ##\phi(x_1,x_2,...x_n,t)= \int dx_1...dx_n \phi(x_1,x_2...x_n,t) a^+(x_1)...a^(x_n) |0> ## Where ## |0> ## is the vacuum state and ##a(x) |0>=0## The Attempt at a...
  18. Nikhil Rajagopalan

    Standing Wave Fundamental Frequency and Particle Vibration

    For a wave A sin ( kx - ωt) and a wave A sin ( kx + ωt) traveling opposite to each other, on evaluating by applying superposition principle , the resultant displacement function is 2A sin ( kx ) cos (ωt) . For different Node Anti-node configurations we calculate natural frequencies of the...
  19. TheQuestionGuy14

    B Can you measure a particle without breaking superposition?

    Is it possible to measure an electron, and, say, get multiple simultaneous results about it's motion, as you didn't break superposition? (E.g. you could simultaneously read 5mph, 10 mph and 15mph), and could this be used for quantum computers, to store store and gain huge amount of information...
  20. A

    Quantum energy of a particle in a 2 dimensional space

    Homework Statement [/B]Homework Equations Doing this problem like e.g setting the determinant of potential matrix and the ω2*kinetic matrix equal to 0 ,det(V-ω2T)=0,I got the frequency of the normal modes of vibration to be 2ω0 and ω0 where ω0 is the natural frequency, But sir how to treat...
  21. A

    Quantum energy of a particle in 2 dim space

    Homework Statement Homework Equations Doing this problem like e.g setting the determinant of potential matrix and the ω2*kinetic matrix equal to 0 ,det(V-ω2T)=0,I got the frequency of the normal modes of vibration to be 2ω0 and ω0 where ω0 is the natural frequency, But sir how to treat this...
  22. ezfzx

    I Reconciling alpha particle mass

    Ugh ... I remember there was a reason ... but forgot what it was. So here's 3 bits of information gathered from dozens of sources, textbooks, official sites: Alpha particles are identical to Helium nuclei. Alpha particle mass = 4.001506 u helium-4 nuclei mass = 4.0026032 u OK, so ... why...
  23. J

    Acceleration of a particle on a parabola

    Homework Statement A particle moves along a parabola on the x-y plane with equation ##y^{2}=2px## with constant speed ##1000m/s##.What is the magnitude of its acceleration? Homework Equations Parametric equations ##\vec{r}=(b^{2}t^{2}/(2p),bt)##. The Attempt at a Solution...
  24. E

    Phase relation between strain and particle velocity

    I'm trying to understand the following derivation. Starting with the one-dimensional equation for a traveling wave ##u = u_0 \exp{[j(\omega t - \beta z)]}## the goal is to derive the phase relation between strain and velocity. The author first derives the relationship between strain and particle...
  25. I

    I Particle in a box, boundary co-ordinate change

    If you have a particle in a 1-d box with a finite potential when ##0 < x < L ## and an infinite potential outside this region, then the normalised wavefunction used to describe said particle is ## \psi (x) = \sqrt{\frac{2}{L}}\sin(\frac{n\pi x}{L})##. However, if you had say instead a finite...
  26. R

    Probabilistic data association with a particle filter

    Homework Statement Hello everyone, I have to implement a probabilistic data association filter with a particle filter. I have already implemented a PDAF based on the Kalman filter. The assignment considers a radar (range,angle) tracker. With the state s containing the x, y position and the x...
  27. F

    Moving a particle from point A to B on a efficient way in GAMS

    Hello everyone. I am triyng to calculate the route which takes less time to go from point A to point B in the presence of a constant flow (I. E. a simple version of Zermelo's navigation problem) using the GAMS software. However, if I put both points on a straight line and make the constant flow...
  28. M

    Angular Momentum of a Moving Particle

    Homework Statement A point particle travels in a straight line at constant speed, and the closest distance it comes to the origin of coordinates is a distance l. With respect to this origin, does the particle have nonzero angular momentum? As the particle moves along its straight-line path...
  29. G

    Radio Frequency Acceleration in Particle Accelerators

    So, I've been really interested in Particle Physics since 6th grade when I did a project on particle accelerators. I understand most of it, except for one thing, the radio frequency cavities which are used for acceleration. I just want to ask, how do the Superconducting Radio Frequency Cavities...
  30. J

    B Does light only behave like a particle when observed?

    My question is - is all light a wave until observed, then wave function collapses and behaves as a particle? This is far fetched (and i don't subscribe to it!), but theoretically could light from a distant object passing through a double slit experiment and exhibiting a particle pattern be...
  31. Copernicuson

    I Are There Any Theories for the Mystery Particle at 28 GeV?

    Hi, I was wondering if there are any proposed ideas for the mystery particle at 28 GeV? Please see article http://theconversation.com/mystery-particle-spotted-discovery-would-require-physics-so-weird-that-nobody-has-even-thought-of-it-106260
  32. J

    I Can Cosmic Rays Be Economically Used in Particle Accelerators?

    would it be a more economical idea to accelerate cosmic rays from the atmosphere which are already traveling at 43 percent of speed of light as particles in a particle accelerator. Do you think that this would be more economical in principle or that you could achieve higher collision speeds?
  33. I

    B What Does It Mean For A Force To Act On A Particle?

    I know this is kind of a dumb question but please forgive me it's been awhile. Is it enough for a particle to merely "feel" an external force F to state that "F is acting on the particle"? ie if the particle was confined in a potential well and experiences F but does not move. or does...
  34. DracoMalfoy

    Finding the Kinetic Energy of a particle in 2mol of nitrogen

    Homework Statement What is the kinetic energy of a particle in 2mol of nitrogen gas at atmospheric pressure that is within a volume of 100m^3?a. 1.27X10^-17J b. 3X10^5J c. 6.8X10^-16J d. 2.97X10^7 e. 9.9X10^-14J Homework Equations PV=nRT n=Numberof particles/Na Na=6.02x10^23 R=8.13 J/Mol The...
  35. Hououin Kyouma

    B How can you ensure that the particle has already been entangled?

    There are several questions I am wondering. 1. If I give you a particle, how can you ensure that the particle has already been entangled? 2. If I give you a pair of particles, how can you ensure that these particles have already been entangled? In how many ways, e.g. in the...
  36. W

    Particle spin probabilities

    Homework Statement A beam of spin ##\frac{1}{2}## particles is prepared in the state: ##|\psi> = \frac{3}{\sqrt{34}}|+> + \frac{5i}{\sqrt{34}}|->## a) What are the possible results of a measurement of the spin component ##S_z##, and with what probabilities would they occur? b) Suppose that the...
  37. cookiemnstr510510

    Charged particle moving in circular path in a magnetic field

    Homework Statement A deuteron nucleus (consisting of one proton and one neutron) has a mass of 3.34x10-27kg and a charge of 1.602x10-19C. The deuteron nucleus travels in a circular path of radius, 6.6mm, in a magnetic field with magnitude of 2.1T. A) Find the speed of the deuteron nucleus B)...
  38. Arman777

    Is the Mystery Particle Discovery Just Media Hype?

    Mystery particle spotted? Discovery would require physics so weird that nobody has even thought of it http://flip.it/Y6A5he Could be DM ? Or really an error
  39. Robin04

    Particle falling inside a sphere due to gravity

    Homework Statement We drill a hole from the surface of the Earth to the other side through the center, drop a test particle and measure the time it takes to come back. How does this time depend on the radius and density of the Earth? Homework EquationsThe Attempt at a Solution The gravitation...
  40. Robin04

    Collision of a charged and an uncharged particle

    A charged and an uncharged particle collide. What will be their charges after the collision? The average of the total charge?
  41. B

    What Was the Initial Energy of a Positron Entering a Plastic Slab?

    Homework Statement Q- a positron emerges normally from a 4-mm thick slab of plastic (density= 1.14g/cm^3) with an energy of 1.62 MeV. What is the energy of the particle when it entered the slab? Homework Equations Range when 0< T <= 2.5 MeV: R= .412+T^[1.27-.0954*ln(T)] where T is kinetic...
  42. Krushnaraj Pandya

    Angular momentum of particle about the origin

    Homework Statement A particle (5 kg) moves with constant velocity 2 m/s along the straight line 2y=3x+4, the angular momentum of the particle about origin is? Homework Equations L=r x p The Attempt at a Solution For a 2d problem we take the component of velocity perpendicular to the point...
  43. R

    Particle Newtonian Mechanics: Father Pulling 100 lb Sled

    Homework Statement The problem states that there is a father pulling a 100 lb sled with a force of 100 lb at some angle. At what angle does the father have to pull in order for the sled to accelerate at 25 ft/s^2? The coefficient of kinetic friction here is given as 0.04. Homework Equations F...
  44. J

    Position of particle in inertial reference frame

    Homework Statement The position of a participle in a fixed inertial frame of reference is given by the vector r = i(x0 + Rcos(Ωt)) +j(Rsin(Ωt))where x0, R and Ω are constants. a) Show that the particle moves in a circle with constant speed Homework Equations F = mv2/r The Attempt at a...
  45. Mahavir

    I Particle interactions with matter

    Hello, Currently studying electromagnetic radiation and ionisation and a bit stuck on a concept. From what I think I've understood, an electromagnetic photon enters matter, and if the energy is > 10eV it will displace an electron causing it to ionise (and therefore moving out of the atom). This...
  46. J

    I Particle creation, energy density and the Compton wavelength

    The Compton wavelength of a particle is given by $$\lambda=\frac{h}{mc}.$$ One can construct an expression for the energy density ##\rho## of a particle of mass ##m## given by $$\rho = \frac{mc^2}{\lambda^3}=\frac{m^4 c^5}{h^3}.$$ What is the physical significance of the mass scale ##m## in the...
  47. arturo

    Can we find work done on this particle, and if not, what are we missing?

    Homework Statement A force varies with time according to the expression F=aΔt, where a = 2.0 N/s. From this information, can you determine the work done on a particle that experienced this force over a displacement of 0.50 m? Homework Equations W = F*d Vf = Vo + aΔt F = ma The Attempt at a...
  48. M

    Evolution of a particle in a well

    Homework Statement I posted a picture of the question https://imgur.com/a/8byywYL Homework Equations P = $$(<\psi_{n}|\psi_{o}>)^2$$ The Attempt at a Solution I am guessing that I compute(denote by ##\psi_{o}## the ground state of the old well and by ##\psi_{n}## the ground state of the new...
  49. T

    I Charged particle acceleration across a potential

    Hello, I haven't been able to find the answer to this anywhere. When calculating the energy gained by a particle that is accelerated across the gap of two cavities (e.g. Dees in a cyclotron, or charged cylindrical cavities of a linear accelerator), does one need to take into account the size of...
  50. P

    I Velocity of Particle vs Inertial Frame Velocity

    Hello all, This post is in reference to a previous homework post, found here: https://www.physicsforums.com/threads/show-that-f-gamma-3-ma.338744/ That thread is closed to further replies. Probably because it's nearly 10 years old. That thread is about deriving relativistic force from the...
Back
Top