Hot Definition and 572 Threads

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.

Apparently, I heard CA glues were toxic while being warmed through hot glue guns. How long would an average human being survive if he were stuck in a closed room with his glue gun left one? I'm just wondering based on safety measures...since I heard CA held cyanide, I was wondering what the...

Can Hot Wire Measurement run in Water Tunnel? Thanks a lot!

Why when sometimes touch the glass balloon around the light bulb, it is hot?

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...

Tined new potatoes do not attempt to fry them, they explode, i have just finished cleaning all the cooking oil of the walls ceiling etc, all i did was pour the potatoes into hot fat and within minutes they started exploding, i saw one jump 6 inches into the air, i could not get near the pan...

I have the answer, it is because the refrigerator is not in freeizng mode when the cold ice cube tray is placed inside. When the warm tray of water is placed inside then the temperature lowers considerably and the thermostat switches the freezer into freezer mode. A common complication I...

Homework Statement The radium isotope ^{223}{\rm Ra}, an alpha emitter, has a half-life of 11.43 days. You happen to have a 1.30 g cube of ^{223}{\rm Ra}, so you decide to use it to boil water for tea. You fill a well-insulated container with 340 mL of water at 16.0^\circ {\rm C} and drop in...

Suppose in summer, two consecutive days, the first was hot at 30 centigrade, the second at 20 centigrade. Both was cloudless in the afternoon. There haven't been any rain prior to the days nor after for about a week. What caused the second day so much cooler then the first even though they...

Homework Statement A hot air balloon rises from the ground with a velocity of (2.0m/s)y. A champagne bottle is opened to celebrate takeoff, expelling the cork horizontally with a velocity of (5.0m/s)x. When opened, the bottle is 6 m above the ground. a) What is the initial velocity of the...

For this question: http://tinyurl.com/3bozr6 the answer is c. Can anybody kindly explain how this is achieve by refrigerator? Because according for what I study so far , the energy is transfer from hot part to cool part...

For those interested, I have just received my third electricity bill after the installation of my solar hot water heater. Currently, I have realized at total of $158 "saved." Putting that against ~$3500 of total cost, then somewhere between $1200 and $2000 federal tax credit , and the...

Homework Statement A Hot air balloon is traveling vertically up- ward at a constant speed of 2.6 m/s. When it is 19 m above the ground, a package is released from the balloon. The acceleration of gravity is 9.8 m/s^2. After it is released, for how long is the package in the air? Answer...

I have 2 problems that i can't do You apply a force of 0.35N up to lift a fork. The resulting acceleration is 0.15m/s2 up. Determine the mass of the fork (the answer is 35g-why?) A hot air balloon has acceleration of 1.10m/s2 down. The mass is 315kg. What is the upward force on the...

was just watching this video(The joy of science) on thermodynamics, and the proffesor of the video said "hot objects don't always accelerate." this went against what i previously thought. tried googling it but couldn't find an answer. i don't know how to picture this. how?

How might hot jupiters arrrive close in, since gas sufficient for their formation would be seem to be further outward? It might seem to require a 3-body 'solution'. That is, must another gas giant have been in the mix for much earlier stages? Perhaps ejecting 1 giant, and retaining the other in...

Homework Statement A hot-air balloon is descending at a rate of 2.0 m/s when a passenger drops a camera. If a camera is 45m above the ground when it is dropped, (a) how long does it take for the camera to reach the ground(b) what is the velocity just before it lands? Let upward be the...

I can't find my favorite tea anymore so I am looking for a new one. I'm looking for something without caffeine so I can drink it before bed. I also want something that is available in a tea bag; loose teas are too inconvenient. I tend to like fruity and tangy blends, and sometimes, spice...

Very hot question(Answering will get you 5 dollars, just kidding. Because Earth's rotation is gradually slowing, the length of each day increases: The day at the end of 1.0 century is 1.0 ms longer than the day at the start of the century. In 24 centuries, what is the total (in hours) of the...

If you suddenly put your hand into very hot water it feels cold (or atleast, it's hard to tell if it's hot or cold) for the first second. Why is this so? Thanks.

I'm interested in the physics behind racing Hot Wheels cars. When you release the cars from an incline, what makes some cars go faster than others? What would be the most important factor of a fast car (ex. weight, aerodynamics, etc.)? How could I modify a car to go faster? Thanks!

I'm looking forward to tasting some of turbo's habanero sauce. :-p

I'm a chemical engineering undergraduate studying in Canada right now. I'm not too sure what my future looks like, so I'd like to have some opinions on whether it's a good engineering discipline to stick with. 1. I'm interested in a career in R&D, but I hear that you need at least a PhD. I'm...

As we all know, core body temperature is around 98.6 degrees Farenheit. It is more comfortable for one to wear less clothing when the temperatures are in the 80s and 90s (since this allows core body heat to more easily disperse outside). But what if the temperatures are in the upper 90s and...

http://news.yahoo.com/s/ap/20070701/ap_on_sc/rethinking_nukes There is also fervent anti-nuke opposition waiting to be re-stoked. Jim Riccio of Greenpeace said nuclear advocates are exploiting global warming fears to try to revive an industry that's too risky to fool with. "You have...

"glow" of emission lines vs. hot objects I was wondering how the mechanisms differ between the following two scenarios: A. The glow of emission lines (I think it has to do with the Bohr atom) B. The glow of hot objects (I think it has to do with Blackbody radiation)

"glow" of emission lines vs. hot objects I was wondering how the mechanisms differ between the following two scenarios: A. The glow of emission lines (I think it has to do with the Bohr atom) B. The glow of hot objects (I think it has to do with Blackbody radiation)

Is there any reason why most hot things alost always begin to get the tinge of red??

Hi all, Sat this problem in an exam recently and it's got me wondering. First off, you have a reservoir at a lower temperature T1. You also have a mass of water at a higher temperature T2 (in this case it was 10C and 100C, I can't remember the mass but let's say it was 1, and Cv 4.2). First we...

Hello people :smile: Again I need some help...:shy: I'm looking for a type of cloth that can be used to seal a gas at up to 700 degrees C (about 1200 F) and a pressure difference of up to 1 atmosphere. Just to explain a bit more, I want to seal gas between two sections of a jet engine...

This cute mechanical engineer mentioned in a message that he had designed some manifolds, so that's why I'm asking this (in addition to my general interest in physics, of course). I'm not sure if they were intake or exhaust manifolds, but that's not the problem now. I figured that...

http://www.twilightus.net/adam/weather.gif :cry: :cry:

I will be writing my final exam tomorrow evening, and I am currently stuck on the following practice problem. It would be very nice if someone could help me out and I will remain eternally grateful for your help! 1) (Multiple Choice) Which of the following statement(s) about Cold Dark Matter...

A particle of mass 12 grams moves along the x axis. It has a restoring force F= -0.06 N/m. If it starts from x=10 cm with a speed of 20 cm/sec toward the equilibrium position, Find its amplitude, period, and frequency. Determine when the particle reaches the equilibrium point for the first time...

To start things off i am using DSC (Dipsersion Strenghtened Copper) 99.58% copper 0.19% Aluminum Oxide 0.16% Oxygen Less than .01% Iron Less than .01% Lead max tensile is about 10 breaking pounds or 88ksi i think for...

Hey guys, I'm new to these forums so I'm hoping i have posted this question in the appropriate thread. Recently, i noticed the electric heater in my fish tank had a volume of water around it all times which was rising, it made sense to me that the water surrounding the heater would be rising...

I play around with HO slot cars and would like to wind my own "hot" armatures but I can't find any sources of direction. It seems like everyone knows how to do it so why explain:frown: I've bought a couple of pounds of mag wire in different guages but I would hate to tear up a good one to...

Can someone briefly explain the definition or the difference between a cold and hot transition of light? Hot transition involves a change in an atoms vibration and standing wave patterns from absorbtion of higher frequency, such as skin sunburn from long exposures to ultraviolet light or...

everybody knows that hot air rises. but on thinking about heat as the knetic energy of molecules, heat transfer just becomes another word for collisions between molecules (looking at a gas) right? so surely hot air, in it's attempt to rise from the bottom to the top of a container, would...

I would think that after 4 billion years the thing would stabilize and cool off. I can't imagine that this is all due to continental drift and what not. Could there be an enormous nuclear fission furnace at the center of that iron core? Does solar wind drive an electric current in the center...

1. A woman informs her engineer husband that "hot water will freeze faster than cold water". He calls this statement nonsense. She answers by saying that she had actually timed the freezing process for ice trays in the home refrigerator and found that the hot water does indeed freeze faster. As...

I've always wondered how people are able to walk on hot coal without suffering from burns. Moreover, earlier, a teacher demonstrated to my class how if one spills liquid nitrogen on one's hand in open air that one does not suffer from frostbite, but only feels the cold temperature. I got...

Here I've seen different solutions. Some people simply add a T to the hot water pipe from the heater and run the circulation pipe alongside the hot water pipe connecting the two near the end. They then connect a pump to this. I don't really see how this has any effect. Wouldn't the hot water...

Good morning everbody, very good indeed. Well, tell me what you think : http://dorigo.wordpress.com/2007/01/19/a-21-sigma-eccess-of-mssm-higgs

In your opinion what are the top specializations of EE that are in demand. What is the hardest to get into and yet most rewarding? I've taken some introductory courses in the following subjects and done pretty well. Right now I see myself going into Analog but I am so interested in RF. Is RF...

I'm looking for a way to estimate the size of hot water accumulators for residental buildings. I have made myself graphs describing the varying demand of hot water during a typical day, and then compared this to a graph describing the production rate of new hot water. This is according to a...

Hi all! Could anyone tell me, a final year student in mechanical engineering preparing for his final year project, what the hot reserach topics in heat transfer are?

Is "Global Warming" hot? What is your sense of public awareness of and the attitudes towards this subject? It seems to me that in the US we have finally reached critical mass. Since to a large extent TV merely feeds people what they want to watch and what they already believe, and since TV...

Is it normal for air conditioners to completely suck when you need them to not suck? It's 107 today and its been around 85-88 degrees up here where the air conditioner is. Do air conditioners just fail to work after it reaches a certain freaken temperature or something? Our filter is newly...

The Mpemba effect is about the phenomena of hot water freezing faster than cold water. Does anyone know how to pronounce Mpemba?