Cool Definition and 276 Threads

i have a hive syndrome that makes me flare when im in a heated enviroment, in summer i hive loads, and keep my room cool with a fan. but in winter my flatmate wants the heating on as she is cold, but i need my room to remain cooler because i will flare in hives. shes saying that even if i close...

Rectangular office accommodates 10 people, two doors and one wall has windows the full length of the room. My office is within, no windows and no direct sunlight there. The temperature went from 20C at 8am to 25C by 3pm. Similar temp in the main office. All windows were open so my thinking is...

I got this watch nearly a year ago and love it. It is a celebration of the Apollo 11 moon landing. The planets orbit to tell you the time. The stars and planets glow in the dark as well!

https://www.latimes.com/obituaries/story/2023-04-16/ahmad-jamal-dead-92 https://www.nytimes.com/2023/04/16/obituaries/ahmad-jamal-jazz-dead.htmlhttps://www.npr.org/2023/04/16/846207919/ahmad-jamal-obituary

Good morning sirs, I have a standard bottle of wine made by glass, 0.75l. I suppose it's 20deg and I'd like to know how much time I need to lower the temperature of 4deg, considering outside it's winter, no wind, simple convection. I read some theory and I discovered some reference to Nusselt...

Here is one I found on Twitter: Please add others!

Whenever I open Refrigerator two things come in my mind Open door with fast speed, take the object out of it and close with fast speed.[so that less cool air escape] 2)Open door very slowly, take out object and close slowly.[assuming the cool air will escape slowly] Both the above conditions...

Short satire piece: https://www.mcsweeneys.net/articles/signs-you-work-in-the-cool-lab

Hello! I'm having some problems solving a task.. "Ice with temperature -12°C is used to cool down water from 98°C. to 55°C. . Specific heat capacity for ice = 2097J/kgK, Secific heat capacity water: 4180 j/kgK. Heat of fusion for water is 334,4kJ7K. The mass of the water is 20kg." ∆T water =...

I really like watching peoples animation and movie short videos on Youtube, so I thought I'd create a thread here where people can share animated videos that they've seen recently which they thought were good. Here's a 1st one: "Happiness"

My thinking is that a paint coating will slow down heat loss due to an insulation effect, but at the same time speed up radiative heat loss from the outside black paint surface. I am unsure though which effect may be the greatest and therefore the net effect on tube temperature. Many thanks

Summary:: TLDR : Drink cooled from 17 C to 7 C with either ice cubes (method 1) or soapstone stones (method 2). Calculate the mass of each item that would be needed to cool the same drink. Given the information provided. In order to cool a drink (“cola” for example) from a storage-room...

Colonizing white dwarf s.

Molecular regulators of inter-cellular tension, at triple junctions between cells, in an epithelium have been described. Probably behind paywall. Interpretation by non-authors. Research article. An epithelium is a kind of tissue, where the cells are arranged in sheets. These cellular sheets...

Scary and Cool e-wheel tech: - upto 45mph - upto 128 miles driving range (170 lb person at 20mph) - battery charge 8hrs or with dual chargers 4 hrs - $2850 https://www.ewheels.com/product/new-veteran-sherman-18-100v-3200wh-battery-2500w-motor-1000-deposit/?affiliates=152 on youtube:

I watched this on Zoom yesterday... which was also livestreamed on Facebook, and is now posted there http://www.scic-conference.com/ (has the schedule) (has the video) https://www.facebook.com/scicUnconference/

Hello friendly people of PF So I have a tank with about 250 litres of mineral oil in it. and computer servers are immersed in it. the oil keeps the servers cool but get's hot in return. What different (economic) ways are there to cool the oil down? The best way I could think of was Oil-water...

I have two more questions:- (1) Can we calculate the time it takes specifically for water to radiate all its heat? (2) Heat is illustrated as kinetic energy of molecules, so why collision between particles should result in the conversion of kinetic energy into radiation. Why conservation of...

Summary:: "So about a year ago I started a compendium. Tweets, yes, but also videos, apps, memes… anything stimulating or arresting" - Ben Orlin A Compendium of Cool Internet Math Things Some of these are physics oriented.

There are been many threads at PF on the perception of color. I would like to share a good video on the subject, which contains many interesting visual effects. This is from the Technology Connections channel, which has many videos of interest to our community. I encourage you to browse around.

Summary: Last night's View of the Moon from Northern Illinois Even with a few day-old waxing moon I was able to easily see all of the moon's outline. As the moon set last night it lined up with the street I was on making it appear vastly larger than normal. I was in awe as it drop down.

Well I think it is cool anyhow ;) Here is a dependency-free variable-order double pendulum simulation in about 120 lines of Python. Have you seen the equations of motion for this system? As usual, this is based on code that I have provided here, but trimmed for maximum impact. Can you see...

So I was taught in school that heated low density gases produce spectral lines and cool low density gases absorb their spectral lines. I mentioned this to my husband and he asked me what the definition of hot and cool were and I had no idea. The more I thought about it, the more confused I...

I have probably known the stock answer to "How does sweating cool a person down" since elementary school. I'm looking for a far deeper answer to the question on this thread. I googled the question, and the first answer google provided is this answer from the website www.explorit.org: "Imagine...

I wanted to deposit thicker layers of copper on glass with the deposition system I put together, meaning I would need to keep current flowing through the tungsten heating element longer. But with 70 or 80 amps @5 volts, the electrodes wouldn't be able to survive the heat generated. So my...

Just got interested in cool graphs. Here are some I made: https://www.desmos.com/calculator/19lqdi8yid https://www.desmos.com/calculator/zc6qajdh3d https://www.desmos.com/calculator/zsydsv714y

Glowy with lots of brass.

Ben Eater's cool site has a couple of videos using Grant Sanderson's (3blue1brown youtuber) quaternion videos and making them interactive. WHile the discussion is going on you can manipulate the content. https://eater.net/quaternions/

Some background: I'm a mathematical physics (it's not focused on the field titled mathematical physics specifically, but rather it's a general math and physics degree) student in Canada. (Update if you saw my last post about struggling in linear algebra 2 - I have been doing very well in groups...

There are a lot of strategies that can help to avoid it being total hell indoors in this hot weather. We've had many threads about Air Con and Air Coolers but these things are not widely used in the UK and it's too late to contemplate AC because they've all been sold! There are other ways...

When a high mass star starts to fuse heavier elements, the core heats up the outer layers enough to for them to begin fusion of their own. My question is: because the star hasn't gained any mass, but it has increased in temperature a lot, why doesn't the star expand and cool like a red giant...

Red dwarf stars are main sequence stars but they have such low mass that they’re much ' cooler' than stars like our Sun. Then Simple question here : Sun is cool or hot??

AIUI, a white dwarf is a remnant from a star where the nuclear fusion process has exhausted since there is not enough pressure, etc., to continue to fuse heavier "metals" like carbon & oxygen, and that it is white because it is very hot, and thus relatively flat in the visible spectrum. It...

I placed a hot metal lid on a cool surface. When i tried to pull it up, it had a lot of resistance, i had to really try to pull it up. I could hear sounds under the lid, I'm guessing it was boiling water. What do you think could have caused this resistance?

As Feynman says, talking about a liquid in a container : "So the liquid gradually cools if it evaporates. Of course, when a molecule of vapor comes from the air to the water below there is a sudden great attraction as the molecule approaches the surface. This speeds up the incoming molecule and...

If we have two identical objects each placed in rooms at 25°C room temperature. In the first room, the object is at 0°C. In the second room, the object is at 50°C. Which object will reach the room temperature of 25°C first?

Hlo

This is really cool using PVC pipes and 6 motors. Imagine how you could extend it with various sensors and making it autonomous:

I'm currently an EE student going to UC Colorado Springs, definitely a decent university but I'd like to really get the best out of my education and since I'm on the Post 9/11 GI bill I don't have to worry about residency requirements. I have been keeping my GPA well polished to be able to make...

The title says it all. I would like to know how to calculate the time for boiling water to cool off. Assuming the temperature of the room is not changing and there is a constant degree of air flow over the water. Really I would just like to know how to go about calculating this. Thanks in...

How long does it take for the temperature on Earth to cool down after the sun has set? I want to know if the total solar eclipse will change the temperature.

How do you calculate the time to cool down a 60'X60'X50' building filled with outside air at 96°F to 65°F with 14,250 CFM of supply air at 55°F?

http://www.nature.com/news/lights-camera-crispr-biologists-use-gene-editing-to-store-movies-in-dna-1.22288 "The technical achievement, reported on 12 July in Nature1, is a step towards creating cellular recording systems that are capable of encoding a series of events, says Seth Shipman, a...

so I am trying to move cool air from my room on the third floor to the living room on the second floor, but it does not seem to be working as well as I would like it to. I have the windows open and fans pointing "in" upstairs while downstairs they are pointing "out". Do I need fans directing...

some may not have seen this video done in a vacuum chamber enjoy

Giant standpipe type overflow from a dam. https://rumble.com/embed/vfzc9/

How does compression cool water in a household water cooler? I was reading and it says, " The water inside the water cooler is fed into a reservoir, where it is cooled using a refrigerant. A refrigerant is a cooling medium that is circulated in pipes that are located close to the reservoir in...

Homework Statement In the year 2004 the USA produced 1787 TWh of electrical energy in conventional thermal plants and 476 TWh in nuclear plants. Assuming 30% efficiency for nuclear plants and 40% for conventional thermal plants, determine the (annual) volume of cooling water required to cool...

I found this optical illusion today on the internet. This posting is accompanied by an explanation of how it works, that invokes lateral inhibition among neurons in the visual system. There is another version of this available on the internet where they show two versions. one version has red...