Liquid Definition and 1000 Threads

A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. As such, it is one of the four fundamental states of matter (the others being solid, gas, and plasma), and is the only state with a definite volume but no fixed shape. A liquid is made up of tiny vibrating particles of matter, such as atoms, held together by intermolecular bonds. Like a gas, a liquid is able to flow and take the shape of a container. Most liquids resist compression, although others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly constant density. A distinctive property of the liquid state is surface tension, leading to wetting phenomena. Water is, by far, the most common liquid on Earth.
The density of a liquid is usually close to that of a solid, and much higher than in a gas. Therefore, liquid and solid are both termed condensed matter. On the other hand, as liquids and gases share the ability to flow, they are both called fluids. Although liquid water is abundant on Earth, this state of matter is actually the least common in the known universe, because liquids require a relatively narrow temperature/pressure range to exist. Most known matter in the universe is in gaseous form (with traces of detectable solid matter) as interstellar clouds or in plasma from within stars.

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  1. U

    Would Solvent Move Through a Membrane to Air in Osmosis?

    Hi all, In osmosis a solvent moves across a semi-permeable membrane when the solvent is on both sides of the membrane but the concentration of the solute differs. Normally solvent moves from the side with high osmotic pressure (solvent containing less solute) to side containing more solute...
  2. D

    Standard Entropy of a liquid at melting point with no S(298.15) given

    Homework Statement Vapour pressures of a liquid have been measured and fit to the following equation: Log10 P (mmHg) = -3571/T + 8.999 The melting point has been determined to be 392.7 K. A Cp value given for the liquid is 250 J/mol K and the ΔSvap is 117.20 J/mol K Homework Equations...
  3. D

    Standard Entropy for Liquid at Melting Point

    Homework Statement The vapour pressures of a liquid have been measured and fit to the following equation: Log10 (mmHg) = -3571/T + 6.124 The melting point has been determined to be 392.7 K. Calculate the standard entropy of the liquid at the melting point. Homework Equations...
  4. U

    Liquid flowing through a capacitor

    Homework Statement A parallel plate capacitor having plate area equal to A and the separation between the plates equal to d, is placed in a stream of conducting liquid with resistivity r. The liquid moves with constant velocity v parallel to the plates of capacitor. The complete system is...
  5. U

    Find period of vibration of liquid

    Homework Statement A liquid (density ρ) is poured into a bent tube such that the two halves of the bent form angles α and β with the horizontal. The length of liquid column is l. If one of the liquid levels is depressed and released, the levels begin to vibrate. Find the period of vibration...
  6. varunika

    Measuring Liquid Flow: Steady or Not?

    how can we know whether the flow of liquid is steady or not from its velocity?
  7. U

    What is the specific heat of the liquid?

    Homework Statement A point source s emits thermal heat energy H every second uniformly in all directions. A cylindrical container with radius R, which contains a liquid of mass m, is placed at a distance h above the source, look at the picture. After t seconds, the temperature of the liquid...
  8. M

    Thermal Equilibrium With Insulated Liquid And Gas Containers

    Homework Statement A beaker with a metal bottom is filled with 20g of water at 20∘C. It is brought into good thermal contact with a 4000 cm^3 container holding 0.40mol of a monatomic gas at 10atm pressure. Both containers are well insulated from their surroundings. What is the gas pressure...
  9. T

    Calculating Centripetal Force in a Bent Tube

    Homework Statement A horizontal tube of uniform cross sectional area 'A' is bent in the form of U. If the liquid of density 'ρ' enters and leaves the tube with velocity 'v' then how much external force is required to hold the bend stationary ? Homework Equations The Attempt at a Solution I...
  10. B

    Head pressure for liquid in a tank

    Did I answer this right ? An open tank contains liquid with a specific gravity of 1.735. If the height of the liquid is 10 feet, how much head pressure (in inches w.c. (water column)) will it exert? P= (10) (1.735)= 17.35 What is the pressure in PSI? P= (1.735)(0.433)(10feet)= 7.51255
  11. C

    Why is the restoring force for SHM of liquid in a U tube 2pAgx?

    The figure shows a U tube of uniform cross-sectional area A containing liquid of density p. The total length of the liquid column is L. When the liquid is displaced by an amount x from its equilibrium position, it oscillates with simple harmonic motion. The weight of liquid above AB provides...
  12. P

    Green LED in liquid nitrogen turns yellow

    Hi, While experimenting with various LED's in LN2, I noticed some strange behaviour from my green LED's. As expected all LED's (except the green one's) emitted light with a shorter wavelenth (for instance, my yellow led turned to red etc). However, my 2 (different manufacturer type LED)...
  13. T

    What Color is Liquid Carbon at the Atomic Level?

    What color of liquid carbon
  14. A

    Liquid nitrogen transfer into nitrogen purged enclosure

    I am trying to build a system to transfer liquid nitrogen (LN) into a roughly 6'x4'x2' sealed nitrogen gas-purged enclosure. The LN is in a pitcher-style dewar like this http://static.coleparmer.com/large_images/03773_51.jpg but with an open top, and the container I'd like to transfer it into...
  15. M

    Liquid with Lower Density than Petrol: Non-Fuel Options

    Is there any liquid that has lower density than petrol. one more point : it should not be a fuel.Is there any?
  16. D

    Need help dehydrating liquid fruit blends

    I am trying to understand the best way to dehydrate water from a liquid slurry fruit and vegetable blend, without loosing any of the vitamins and nutrition from the slurry. I expect to very thinly spread out the fruit/vegetables on a sheet, use dried convection air to help with the dehydrating...
  17. C

    Can Inkjet Print Head Technology Be Used for Precise Liquid Dispensing?

    Hi, I'm new here! I'm designing a dispensing system with several liquids. The liquids need to be dispensed into a circular area about 3/8" (opening of a bottle). I'm looking for advice, and would like to share my two ideas: A single peristaltic pump where the tube is manually changed. Each...
  18. Entanglement

    Collision between gas molecules with liquid molecules

    What happens when a gas molecule collides with a liquid molecule at the microscopic level ?
  19. Choisai

    SLMS: Liquid crystal vs Digital micromirror devices

    Hi there! I'm interested in Spatial Light Modulators for my project and I was hoping you (whoever you are) could help me. I try to explain everything as compact as possible but it's still quite a story. Sorry for that! For spatial modulation of light, a 'spatial light modulator' is needed...
  20. curious bishal

    Why do solids compress more than liquids under pressure?

    Atoms in solid are more closedly packed as compared to liquid and gases. But we exert more force, some solid gets compressed but liquid doesn't, why? If atoms are loosely packed in liquid than solids, liquids should get compressed...
  21. C

    PCM wax freezing outside solid, inside liquid

    A colleague and I want to model how a slab of PCM (wax) solidifies as it cools off. What I have noticed in my experiments is that temperature sensors on the top and bottom of the slab say it should be solid, as they read well below the melting point. But when I peek at the sample, the center...
  22. M

    Thermal equilibrium for ice being added to liquid water

    Homework Statement 0.05625 m^3 of H2O(s) is added to a thermally isolated system of 20 L of H2O (l). If the ice was initially at 0 C and the liquid water was initially at 95 C, what is the final state and temperature? The Attempt at a Solution I missed class for this so I'm going by...
  23. A

    Liquid Collision Rate: Estimating Molecular Flux

    In kinetic theory a liquid is viewed as an incompressible substance in which the atoms are free to move. I would like to know how to find an expression for the molecular flux in a liquid. By molecular flux I mean the collisions per unit area, where collision refers not to the collision between...
  24. R

    Determining Surface tension of a liquid with Poiseulle's Law

    Hi. I am doing a physics project and we have been told by my lecturer to find out how to determine the surface tension of a liquid using Poiseulle's Law and to describe an experiment on how to do so. I have no idea how you could do this because none of the variables in the law relate to surface...
  25. K

    Liquid pressure in a closed system

    Homework Statement A steel cylinder filled with water contains 3000psi of pressure, completely sealed, walls ≈ infinite thick. No gas is present inside of the cylinder, and no heat exchange. To the problem; if a solid rod/piston enters on top of the cylinder with no possibilities to bleeding...
  26. M

    Substance is in equilibrium between its vapour and liquid

    In Chemistry, if a substance is in equilibrium between its vapour and liquid, does it account for the dissolved gas molecules? I have always heard that the rate of evaporate = rate of condensation in a case like this, but does the rate of evaporation include the dissolved gases escaping and...
  27. R

    Witnessed Supercooled Liquid Phenomenon

    I had a two liter soda bottle stored outside in the cold. When I retrieved it, the contents was still liquid. Upon opening it, however, when the CO2 bubbles began to escape, the entire contents froze almost instantly around the bubbles. I am curious about what phenomenon I witnessed.
  28. E

    Liquid Slosh and Vehicle Stability

    Hi, I'm working on an invention that eliminates liquid slosh in partially filled liquid containers and allows for center of gravity control. I'm wondering if there is a market for such an apparatus where elimination of all slosh is needed. I am aware of baffles, sponges, and diaphragms. A...
  29. I

    Making Liquid Nitrogen at Home: Have You Tried It Yet?

    A while ago I had asked if anyone ever made liquid nitrogen from scratch without using a prepackaged cooling device (cryocooler). Well, I've done it. I'm working on a web tutorial and better video footage. For those who wish to make suggestions on what you would like to see I am submitting...
  30. L

    SEMF Liquid Drop Model Homework: Struggling with (ii)

    Homework Statement See attachment. Only struggling with (ii). Homework Equations The Attempt at a Solution So ultimately after doing everything, calculating B(ε)-B(0) & assuming z>>1 and z2/A > 47 I find that B(ε)-B(0) > 0.048ε2A2/3 I don't really see how this tells me if the nuclei will...
  31. Gh778

    Liquid helium and curved piston

    It's a theoretical study. Like the image showing, the curved piston move in container and need energy for that. In the same time, another piston move up and recover energy. The pressure inside container is always the same (need to control speed of pistons, but there is a pressure). No gravity...
  32. Z

    How to make a liquid with specific gravity?

    How to make a liquid with specific gravity of 4 or 5?!
  33. anubodh

    Liquid oxygen expansion in vaccum

    Homework Statement There are 2 containers.Outside temperatue is -190 degree celcius.(boiling point of liquid oxygen is -180 degree celcius).One is filled with vacuum and can have a minimum height of 6000m and other is filled with liquid oxygen (1140 kg/m3 density) at -190 degree celcius...
  34. andyrk

    Why Does the Surface of a Liquid Slope When the Container is Accelerated?

    Homework Statement When a vessel containing a liquid is accelerated as shown in the attachment its surface slopes as shown, making an angle θ with the horizontal. Does this happen? Homework Equations Consider a differential mass element inside the liquid. It experiences forces F1 and F2...
  35. A

    Relation between liquid water pressure and it's molecular dynamics

    Hello everyone. I'm am looking for some literature (articles or books) containing information about how is the relation between the liquid water pressure (macroscopic thermodynamic quantity) and it's quantum molecular dynamics (collisions, vibrations, etc.). Like: The pressure increase...
  36. Malverin

    Liquid pressure gradient in zero gravity

    Is there any data about such measurements? I think, there has to be a pressure gradient in a floating liquid sphere due to surface tension.
  37. P

    Creating liquid isobutane from r600a

    There is a recent project I have been working on that requires the use of Isobutane as a propellant/solvent, so I have come up with a way to study the chemical compatibility of isobutane: I have a pressure chamber that I built from transparent PVC and opaque PVC with a tire valve as an inlet...
  38. G

    How Can I Achieve Even Liquid Distribution in My Device?

    Liquid Distribution Problem -- please help Hello guys, I'm a mechanical engineer fresh out the college. I'm designing a liquid transferring device, and really really need some advice/help. So, my device right now has one 13mm diameter inlet that divides into twelve 4mm diameter “tubes”...
  39. B

    Level surface of a contained liquid

    It's interesting to me that a liquid, under the force of gravity, in a container has a flat surface. Tell me if my explanation is correct: if the surface of the liquid were uneven, the higher parts of it would be "sitting on top of" the liquid below. Necessarily, the liquid under these parts...
  40. andyrk

    Accelerating Beaker containing liquid

    When a Beaker is accelerating in the x-direction, the water level gets sloped. Why does this happen? Is this situation analogous to the sloping pendulum in an accelerating cart? Similarly why doesn't the water level change in shape when the beaker is accelerated in y-direction? That is, the...
  41. B

    Does the Adiabatic Gas Equation Apply to Liquid Compression at High Pressures?

    Hi all, Hope you can help I am trying to figure out the temperature rise in a liquid subject to high pressures (7000bar in this case) Is the below adiabatic gas equation still suitable? or is there another way of working this out for liquids? T2 = T1(v1/v2)^y-1 P2 = P1(v1/v2)^y Were y =...
  42. B

    Liquid that hardens fast on a chosen moment

    Hello to all, I am new here, with almost the same question like on this thread: https://www.physicsforums.com/showthread.php?t=310911 A question for an artistic project: I am searching for a not too dangerous (glossy white) opaque liquid that hardens very fast on a chosen moment, but...
  43. R

    What will happen when a body is equally dense as the liquid?

    I am studying Floatation in school and I have some doubts. I get that if an object is denser than the liquid its placed on, it will sink, and if it is less dense then it floats. But what happens when the density of both (the object and the liquid) are same? Will it float or sink? My notes say...
  44. Gh778

    Pressure inside a liquid planet in rotation

    Hi, I would like to calculate the pressure inside a liquid planet in rotation. How can I do ? Pressure depend of depth under gravity but it depend of rotational speed too. Is it gravity pressure less centripetal pressure ? Is it \frac{1}{2}ρω^2r^2 - ρgh ?
  45. A

    Volume of melted liquid water- physics

    Homework Statement A cube of ice, 30 cm on each side, is melted into a measuring cup. What is the volume of the liquid water? Homework Equations I tried doing 30 x 30 x 30 to get 27000 cm^3 but this answer was incorrect. The Attempt at a Solution Not sure what I am doing wron...
  46. C

    How to Solve a Liquid-Floor Collision?

    Hi friends, I have an issue in solving a Collision of liquid with floor. Please Help me in solving this. Thank you all in advance. The problem is as: https://fbcdn-sphotos-d-a.akamaihd.net/hphotos-ak-ash4/q71/s720x720/1379505_1432382913655481_500299018_n.jpg Attempt...
  47. C

    Wanted High density Liquid For suspension of Solids

    Hello I want to suspend, or really have the sinking effect be slow, different kinds of rocks/ gem stones in a jar. So i don't really know where to start. I want something easy to get, clear, not toxic. I'm going to start with something like corn sryup and see what it looks like. But if anyone...
  48. andyrk

    Surface of a liquid behaving like a stretched membrane

    The surface of any liquid behave like a stretched membrane. Is it because of surface tension or all the possible forces acting on a liquid molecule at the surface? I asked this question because if the furface behaves stretched because of surface tension then it means that the forces making the...
  49. Hyo X

    Order and Disorder in Liquid Water: Investigating the Structure of H2O Molecules

    Does liquid water have ordered structure? I.e., are there significant domains of ordered H2O molecules that maintain crystallinity - translational symmetry - in liquid water at room temperature? I guess this is essentially a hydrogen bonded network - How big are these domains? Or are they...
  50. M

    Filling up a tank with a liquid that has an insoluble, inert gas insid

    Homework Statement Homework Equations The Attempt at a Solution The attempt at the solution has been attached, I'm up to part C on this though, so I haven't attempted d or f. I'll get to those as soon as part c is clear as well as A and B. I don't understand how doing a gas phase mass...
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