Freezing Definition and 169 Threads

It has been below freezing for 3 weeks, 12°F at night and in mid 20s during the day. Yard and garden are frozen 2" deep hard as cement everywhere except 3 row in the garden covered with 1/2" of pine needles. Soil under pine needle is not frozen I can push my finger into the soil 3" deep. How...

I was in doubt if this is the right chapter to place this thread, but it seems there are many talents just here. "we were observing from a decent distance through optics. The weather was frosty, clear, calm. When хххххх appeared from under the arch of the house (he was хххххххх to walk to the...

https://www.atlasobscura.com/articles/what-is-a-hair-freezing-contest I do not know where to post this, exactly. Photos are interesting...

Hi folks, very simple question, but have not been able to find an answer: Assume a vacuum pump pulls air through a pipe. Also assume that within the pipe run, there is an area with reduced cross section, creating a temporary increase in air velocity. Also assume the air is very moist, and is at...

Hello all: I have this question , as we all watch the vaccine of Covid-19 reach the market I had this question if the storage temperature of this vaccine is between -20 c to -70c Why the nano droplets in this liquid do not create ice the liquid is not freezing under that conditions although it...

We fixed our Windows 7 32-bit desktop a few weeks back by buying a new PSU for it (see this thread for details). Now a new problem has started: the PC freezes every now and then. 1. When the PC is powered on, it works fine for some time. Then the problem starts 2. Suppose I am moving the mouse...

I once had a job servicing microwave repeater station. About 1000 ft up on the tower are reflectors/antenna they have heaters that came on at 40 degrees F. Heaters stayed on until about minus 18 degrees F then heaters turned off. When it gets cold enough all humidity in the air freezes then...

I was reading The Refrigerator and the Universe, a nice book about the history of thermodynamics, and they talked about an engine that works on the principle that water expands when it freezes. As I understand their description, it is not a reversible engine, but perhaps it could be made so...

Would a small (of order 5 microns to 0.5 mm) liquid metal droplet, if cooled slowly away from external perturbations and not in the presence of oxygen, retain its highly smooth and polished surface as it froze? What phenomena would influence the surface roughness? I assume that simple density...

There's no thermodynamics forum, so I'll post this here. Things "freezing" in space has always bothered me ever since Tim Robbins removed his helmet while in orbit around Mars...

I've been looking into how adding sodium chloride or calcium chloride to snow reduces the freezing point, and why this occurs. The really simple reason I found on this website: https://www.thoughtco.com/how-salt-melts-ice-3976057 , which simply stated that the salt ions get in the way of the...

Fairly Simple Question: If a clock, I suppose ideally an atomic clock, is cooled to near a Absolute Zero, does the cooling process have any impact on its ability to keep time accurately? If not, what types of clocks would be impacted by the cooling process? I assume any clock that uses a...

From, https://flipboard.com/topic/crystals/freezing-fog-creates-rare-light-pillars-in-wisconsin-on-sunday/f-ca02faf45c%2Faccuweather.com For physics see, https://www.nytimes.com/2017/01/06/science/light-pillars.html

Homework Statement 10 kg water temperature 293 K change to ice ( 263 K) at constant pressure. Calculate the entropy change of system Answer is ##-13.8×10^3 J/°C## Homework Equations ##c_p = 4180 J/kg-K## (water) ##c_p = 2090 J/kg-K## (ice) ##l_{water→ice} = 3.34×10^5 J/Kg## ##ΔS = \int...

Homework Statement Calculate the amount of heat emitted when 12.4 g of water freezes to solid air. Homework Equations heat of fusion = 6.02 KJ 1 mol H2O = 18.02 g H2O The Attempt at a Solution 12.4 g H2O x 1 mol H2O/ 18.02 g H2O x (-6.02 KJ) / 1 mol H2O = - 4.14 kJ I am unsure whether the...

Hello there, I am having a problem to solve in exams. I think it's because am freezing but that's just a speculation. I am a physics-math junior and I study really well, solve without looking at solutions and focus and understand the material. Yet whenever I enter an exam I can always solve the...

Homework Statement If we have a hollow ball completely filled with water which is rolling without slipping on a horizontal ground. If the water freezes which of the parameter will remain unchanged- angular speed, angular momentum, linear momentum, kinetic energy, total energy Homework...

Temperatures at the North Pole are above freezing! Its winter at the north pole, and the sun won't raise there until March 20. There is also a patch of ice free water north of Greenland! Washington Post article here. This used to be unusual. The times they are a changing!

Freezes got so frequent and long, two or three minutes maybe 5x per hour, i was about to get out the splitting maul again. Battery stopped it from going through that one. This one's a desktop. Setting Control Panel / Windows updates to "Never Check for Updates" stopped the freezes...

Homework Statement Homework Equations dQ/dt = -kA(dT/dx) The Attempt at a Solution I tried to use Fourier's law of Conduction on this one. I subbed dT for (Θ0 - Θ1), and l(t) (function for thickness of ice against time) for dx, reason being that the sheet of ice should get thicker. I then...

Hi, I need to find out about the length of time it takes to change from one state of matter to another. This is a food industry problem. For example, how long does it take to freeze a leg of lamb? Does the time it takes depend and anything in particular? Going the other way we can speed up...

This question involves a bit of background, so please be patient. I understand that the heat absorbed by ice's phase change from solid to liquid is much greater than the amount that results from the difference in temperature of the ice and the ice cream batter. So the primary cooling effect is...

I have seen this experiment with cooling down a beer: My question is why is cooling so effective? I was thinking about it and my guess is: Salt breaks down a bond in ice crystals, but this reaction needs energy. It took a energy from environment and all around is cooled down. Are my ideas fine?

hi i am trying to figure out the way to calculate the freezing point of an aqueous solution which have 5 different components. if someone can refer me to an example or give me and example it will be great thanks in advance sharon

When solute particles are added to a solvent boiling point increases, I am quite clear with its explanation (in terms of vapour pressure) but when it comes to freezing point, why does it decrease? What does it have to do with vapour pressure? My textbook says it's because liquid and solid state...

Homework Statement 6g of non-volatile solute dissolved in 500g of water freezes at 272.64K. What is the molar mass of the solute? Data given- Tsolution = 272.64K Kf = 1.8 wsolute = 6g wsolvent = 500g 2. Homework Equations ∆Tf = T0 -Tsolution ∆Tf = Kf × molality (m) The Attempt at a Solution...

Many of the commercial and larger restaurant ice makers require that water temp pumped in for making ice needs to be 45F or higher. Anybody know why? Seemed like the colder the better, this side of freezing, everything would run more efficiently. I'm guessing it's cause however it's piped...

I noticed that my windshield washer fluid has methanol in it to reduce the temperature of which it freezes. I know it freezes at approximately -28°C which gives us a concentration of MeOH at approximately ~30% by weight. However, when I try to calculate the required methanol using the mSolute...

Is there a way to calculate the freezing and boiling point of water that has different levels of CO2 in it?

Homework Statement A 0.350 kg sample is placed in a cooling apparatus that removes energy as heat at a constant rate. The figure below gives the temperature T of the sample versus time t; the horizontal scale is set by Ts = 80.0 min. The sample freezes during the energy removal. The specific...

Dear friends. I am a cardiovascular health researcher writing on behalf of my research team based in Copenhagen, Denmark. We plan to conduct a high-altitude field study on cardiopulmonary function assesed by ultrasound on Aconcagua summit in near 7000 meters altitude. Reports say it will be...

this is pretty cool ( pun intended) Dave

Homework Statement Freezing of water at 273 K and 1 atm which of the following is true for the above thermodynamics process p) q=0 q)w=0 r)ΔSsys<0 s)ΔU=0 t)ΔG=0 Homework Equations none[/B]The Attempt at a Solution [/B] i got r, s ,t since the reaction happens at constant...

I am a structural engineer and have a situation where we have a corrugated plastic pipe formed inside of a square concrete column (pipe is 4" in diameter and column is 16x16). The top of the corrugated pipe is flush with the top of the concrete and open to the atmosphere. The bottom of the...

Well, it's that time of year again in New England and discussions are on about freezing water pipes. I'm being told hot water pipes freeze and burst more often than the cold water pipes. Any believers ?

How fast will water freeze when the outside temp has been -17C for 3 days and my generator blows up so now I don't have power to any pumps and the temp has dipped to -20C My plant pumps 5700 GPM

One of my classmates asked an interesting question that I have no idea how to deal with. Prove that if ##\hbar=1##, then of every 1000 pools, one will freeze in summer! I really can think of nothing at all. Any suggestions? Thanks

Homework Statement Is the freezing point always depressed by a solute even if solute-solvent interactions are stronger than solute-solute and solvent-solvent interaction? What about amorphous solids? 2. Relevant knowledge According to my chemistry teacher's powerpoints, the freezing point is...

Homework Statement *All units given are in standard SI units unless otherwise specified.* *Assume a closed system* How much of -200ºC Liquid Nitrogen is required to completely freeze 200mL (0.2kg) of pure liquid water at 0.00ºC (No change in heat, only a change in state)? Given Values. n=...

In this thread https://www.physicsforums.com/threads/freezing-point-depression.275386/ in ygggdrasil answer I didn't understand this line This greater loss of entropy leads to a lower freezing point. Please explain.

Hello, I am working on a science fair project with my son. His project is about the mobility of polymer chains depending on temperature and pressure. As part of his project we want to flash freeze a piece of plastic to show how brittle it becomes. We bought instamorph, which is polycaprolactone...

Please help. I am Trying to calculate the time taken to freeze a 16" carbon steel pipe that is full of water with no flow. The water is at 20 oC and am using Liquid nitrogen feed into an insulated pipe freezing jacket surrounding the pipe to freeze it. If anyone can help with the calculations...

Hi Everybody, I'm interested in learning what the freezing temperature of brass might be - at what point would it break / snap when tension applied to it, not impact but gradual tension? I have no idea how to calculate this as I am a Carpenter and I guess not the usual user of a forum like...

This question has puzzled me for a long time and there have been many kinds of answer for it. The most sensible explanation I have heard is this one. http://physics.stackexchange.com/a/33026/40382 But then I found another explanation at...

Fruit growers sometimes protect their crops by spraying them with water when overnight temperatures are expected to drop below freezing. Some fruit crops, like the strawberries in the figure, can withstand temperatures down to freezing (0° C), but not below freezing. When water is sprayed on...

Is there a formula or method for determining the time it takes for water to freeze from a certain temperature? What parameters would this rely on?

By definition we have h=u+pv for a system where h=specific enthalpy u=specific internal energy p=external pressure applied on the system v=specific volume of the system The internal energy is arbitrarily taken to be zero at the triple point of water i.e, u=0...

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...

I've seen online that you can get a handful of your ashes sent into space for a hefty fee1 and it got me thinking... Would it be possible when dead to flash freeze the brain and send it up into space in a radiation proof container and just allow it to travel through space like the voyagers do...