Cold Definition and 381 Threads

Homework Statement How many grams of 20 degree C water do I need to add to 100 grams of 80 degree C of water to get the final temperature down to 50 degrees C? Homework Equations I'm sure it's a pretty simple equation, but I don't know it. (I'm studying a lot of different things at once...

A house with AC in a hot climate should be painted white (or covered with mirrors) to reduce absorption of light from the hotter sun and surrounding objects. That seems obvious. But what should cover a house in a cold climate? The house interacts with a system that is hotter than it (the sun)...

Homework Statement A hot body is brought into contact with a colder body until their temperatures are the same. Assume that no other bodies are around. 1.Is the heat lost by one body equal to the hear gained by the other? 2.Is the temp drop of one body equal to the temp increase of the...

A windy 0 °C day perceived as colder than a 0 °C day without wind. I find that strange, given that wind is just air particles with kinetic energy. When those speedy particle hit a body, they should give off some of their energy to that body in the form of heat. But instead cold is perceived by...

Hi My brother has a logitech pure fi anytime alarm clock radio. The problem with it is that when it is cold the speakers do not work properly distorting the sound. This is not very useful as it is cold in the mornings when the alarm goes off (playing a song from the ipod). Now I had an...

assume that i have a cloud of cold dilute Rubidium atoms i know the atomic levels of the Rubidium atom How to calculate the dielectric constant of this gas? Which book can i consult?

http://www.cbsnews.com/video/watch/?id=4955212n So, what should one make of this? I would love to hear what people here with physics know-how think about both the people and the experiments. k

Hey, So I don't have that much of a competitive GPA. I'm wondering how much useful it is to call some schools by phone before sending the application? As in, to make a short yet detailed call about why they should consider my application by having other strong components (such as work...

Okay so i have a project, and this is pretty basic physics but I'm kind of confused. so for those of you how a turbo work, please help me out here. okay so: pV = nKT in thermodynamics. so in a turbo, as air enters the compressor turbine, n and k stay constant correct? however as air enters the...

http://news.yahoo.com/s/afp/20090324/ts_alt_afp/usscienceenergynuclear I guess we'll have to wait and see... Looks like it is being presented at the spring ACS meeting right now.

1. Do you own a dog? 2. Is your dog ever in cold weather? 3. Does he have a doghouse with a heat generator? 4. Is your dog outside for extended periods of time?

To me cold water tastes nice, but leave it for a few minutes to warm (slightly) and it tastes horrible, is this just my taste, or do you find the same, if yes why does it taste different?

Does what we as humans consider "cold" travel through space like heat does? Could a planet have moons that are cold because the planet itself is cold? I know cold is really just air, but could it somehow travel from one astronomical body to another?

Why does the mint flavore make your mouth feel cold? I thought it might be chemistry.

"How cold is it?" Heard this bit on NPR radio today, reminiscent of the old Johnny Carson and Ed McMahon exchanges: "It's really cold." "How cold is it?" "It's so cold that ... " ... and the idea is to complete the statement. Here are a couple they played on the NPR bit: "It's so...

Right now it's a bit chilly in the upper midwest (-21 degrees this morning at 6:00 am; -23 degrees predicted for tonight). When walking our dog this afternoon, my wife and I noticed that the snow underfoot squeaked louder that usual. We observe that snow makes a qualitatively different sound...

http://cdms.berkeley.edu From the discussion in APS Viewpoints. The two experiments taken together—XENON10 superior at lower masses and CDMS II at higher—are now encroaching well into the region where discovery may be lurking, a marvelous feat considering that a scattering cross section of...

For England that is, it is not often we gets this brass monkeys, looking out at the jack i saw one poor tin lid fall on his queen mum, it is minus 10c and jack has layed a carpet about 1/4 inch thick every where, dad had a minor operation canceled because of an influx of accidents, and a local...

Why do batteries loose "omph" when it gets cold? Simple question really; It's well known that car batteries (and others) don't work as well when the temperature approaches -20C. I'm just wondering why? What's the physical reason? Also, if you bring the battery back to room temperature, will it...

Hi, I was wondering, what is a cold burn exactly? We were told that liquid nitrogen (or anything that cold for that matter) can cause cold burns when touched... How can something cold burn you? Or is it not burning you but is it merely named 'cold burn' even though it is simply freezing...

Hi I am living in a 2 bedroom house with base bord heaters but i have also purchesed 3 oil space heaters, my landlord since has givin me a bogus eviction notice because of to much humididiy in the air, his fault really for nothin ensuring propor ventalation when repairing the house but my...

Most of us have heard about it. Some of us know a little about it. Little understand it. I am a 17 year old student, competant in the science and maths, (not to toot my own horn, but it is my best area) Is there a physician (no? physicist (damn that word doesn't look right, oh well, you...

Hi, I was just wondering, if you say "The temperature today was twice as hot as it was yesterday", in which units are people usually referring? Degrees Celsius doesn't make any sense, since it is perfectly possible for something to be twice as hot or cold as 0C... For the same reason I don't...

For past few years/for all my life I have found that I realize I have cold only when I wake up (in the morning time). It comes all of sudden. I never successfully pinned down what caused it. I usually blame the things that I ate in my dinner. I am again in standard cycle. I woke up and...

I have observed that the mice seem afraid of cold weather. They run into warm or hot regions when possible and go back when the tepurature incerase. What controls their activity actually ? Is it sexual urge for mating within the cold duration or fears of cold which might cause sense nerve...

I was wondering why temperatures are so low out there in the vacuum of outer space? my understanding is that a thermometer works by interacting with the medium in which it's located. So when we are in a vacuum, there is nothing to interact with our thermometer to give off or absorb heat. So I...

http://www.physorg.com/news131101595.html "Now, esteemed Physics Professor Yoshiaki Arata of Osaka University in Japan claims to have made the first successful demonstration of cold fusion. Last Thursday, May 22, Arata and his colleague Yue-Chang Zhang of Shianghai Jiotong University presented...

http://physicsworld.com/blog/2008/05/coldfusion_demonstration_a_suc_1.html hey, it's physicsworld.com ...so what's up, anyone got some info?

I'm doing a research paper on the supervoid found in the constellation Eridanus and it was discovered by WMAP which recorded a cold spot where the hole is ... I just don't know why a drop in temperature of the CMB radiation indicates a hole... can anyone explain please?

Recently I was helping a friend of mine nail sheets of felt on a roof, and we finished applying the felt in the afternoon when it was warm. We came back the next morning to nail the shingles on the roof, and the felt was bubbled up. It about 20 degrees colder that morning than it was the...

Hi I am by no means an expert nor have I even ever taken a class on physics. I have always been interested on such subjects however. Here is my question. I am doing research on electrolysis and found something interesting on a wikipedia with regards to cold fusion. "Cold fusion...

Is it true that cold medicines turns off your natural immunities to cold and take control of your body? and when you take cold medicines often you easily catch cold?

A few questions about atoms splitting and some about "cold fusion" Ok first I was thinking, when atoms fuse, they release energy, when an atom is split... it releases energy. Now, since energy is not created nor destroyed but only transferers, if you fuse an atom and then split it again, what...

I have read that hot gases flow better than cold gases. Why is this so? Less dense? Any good readings on it. I am thinking of incoming intake charge (cool) in an engine, and the outgoing (hot) gases. Thanks.

Hello All, Please excuse my ignorance. I have a number of questions about the sun. Space is cold, yes, very very cold, close to absolute Zero. I have heard the argument that it is solar radiation or through convection that the heat from the sun reaches us. However I still can't get my head...

Hello all, I'm having a bit of a problem on a class design project. We have to design a mini-fridge for developing coutries that runs on its own power and must cost under $100 ideally (it can go over if necessary). My group decided to use a hand-crank powered thermoelectric module and fan...

Did anyone else catch the eclipse last night? I drug out the Dob around 9:30 and watched until 11:15 or so. It was brutally cold but totally cloudless and clear for most of the night. Saturn was right there too, at opposition I believe; so I got some good views of it too. I took a bunch of...

How or why would this happen? Did I get two different virus strains? Did my body not finish fighting it off properly the first time?

why do the eskimo's live in alaska? don't they get cold up there?

Hi, Cold blooded animals don't produce body heat to keep themselves warm. Why is this? Is their metabolism more efficient (produce more ATP rather than heat)?

We are looking at placing a normally asspirated diesel engine in a few cold climate. The engineroom will normally be heated. When the engine runs there is a ventilation system that will start up and draw outside air and also expel air from the engine room to outside, this is necessary otherwise...

Experiments have been done in which one volume of water that is warmer than an identical volume of water freezes faster than the cooler volume.Since ice is an ordered structure compared to liquid water does this mean that the walls of the vessel containing the warmer water are able to interact...

by cold welding i mean diffusion bonding, explosive welding, cold pressure welding etc. in what situations would one use these techniques and what are the benefits of employing them over traditional methods such as arc welding?

http://asm.asminternational.org/ht-echarts/3046_OMM120707_figure.pdf

Hi, new here, my first post. Like many people here, I'm no astrophysist, but I have an active interest in our solar system, cosmology in general and I guess astrophysics. Here's my first question. "Are black holes cold?". Given my amateur understanding, I would say yes, they are near...

How come standing outside in cold weather makes my nose run? Thanks.

Why is it that cold wet weather makes joints stiff and ache, the actual temperature of the joint can not change much can it?

An interesting review paper of the search for DM particle(s): Direct Detection of Cold Dark Matter. The search continues. Garth

http://www.reuters.com/article/healthNews/idUSN1530262620071115?feedType=RSS&feedName=healthNews&rpc=22&sp=true

Hi, Something weird happened the other week and I was wondering if anyone here could explain why. I run a pub and our cellar operates at about a steady 11°c all year round (cooler assisted). The other week we were enjoying some pleasant weather for the time of year(16/17°c) then wham! in the...