Tagged Questions
2
votes
2answers
67 views
Why is it faster (as in proportion to volume) to boil 4 cups of water than to boil 2 cups?
I did an experiment where I boiled two cups (500ml) of water in a kettle, and it took 1:30 minutes to reach around 98 C, average. However, when I boiled 4 cups of water, (1L) it only took me 2:30 ...
1
vote
1answer
72 views
Does brown but transparent swimming pool water heat significantly faster than western style highly chlorinated pools?
Eastern European swimming pools are often brown tinted water. i was told it was the color of the chemical to keep the pools clean, but who knows. These pools did not smell unsanitary and may have even ...
2
votes
0answers
19 views
Can one get clear ice crystals from a dirty suspension?
Euteictic freeze crystallization is a method where an electrolytic solution is cooled and separated into a stream of (relativly) clean, pure ice and a salty brine. I know anectdotally of wine ...
0
votes
1answer
47 views
Calculating the coefficient of thermal expansion in liquid
I am trying to write a matlab function that calculates the coefficient of thermal expansion of water from a given temperature. From what I understand the thermal expansion coefficient is calculated as ...
0
votes
1answer
48 views
Time constant of ice melt
I'm familiar with problems of "how much ice can you melt given some amount of energy", but I'm writing to get some clarification on the time constant of this event. This question might be somewhat ...
1
vote
2answers
83 views
How long will a water drop exist until it evaporates based on ambient conditions?
How long will a water drop exist until it evaporates based on ambient conditions? I am looking for a simple equation or table that would tell me how long a water drop may exist until it evaporates ...
-1
votes
1answer
91 views
Sensible heat question (solving for temperature)
If $55 034.175 \rm{kJ }$ of heat are transferred to $150 \rm{kg}$ of ice at a temperature of $-12.15 ^\circ \rm{C}$, calculate the temperature of the resulting water.
Using $Q = mc(t_2-t_1)$ or ...
3
votes
3answers
247 views
How can my water cool down more quickly?
I have a cup and I can only pour hot water inside, I wanna know whether the heat will dissipate more quickly with more water or less water?
How about the occasion when my cup is well covered?
0
votes
1answer
109 views
Temperature Vs. Volume of Water
Here and here it states that water is at its highest density around $4^\circ$ Celsius. I know very little physics and a Google search has left me without an answer. I am teaching an ODE class in the ...
2
votes
3answers
112 views
Why is there more steam when water is subject to less fire?
When I cook things, such as scallop and salmon, I found that the food may be more tender if I wait till the water boils (at 100 C) and immediately turn the fire lower so that the water is not bubbling ...
0
votes
2answers
137 views
Why laundry dry up also in cold/frost?
Why laundry dry up also in cold/frost? When you have frost, water in the clothes should freeze, but if clothes are dry, then it should be possible that steam in the clothes does not have time to ...
0
votes
1answer
121 views
What is the ion drag mechanism in dielectric heating?
While reading about dielectric heating on Wikipedia, I read about the ion drag mechanism but there wasn't enough information about.
I know there is another Phys.SE question talking about the ion drag ...
0
votes
1answer
49 views
Action on Lard Oil
If water is mixed with lard oil and heated (creating some super-critical liquid with water), how does this affect the volatility of the mixture in comparison with its purity..?
So, My question is: ...
1
vote
2answers
155 views
How does blow-drying a mirror keep it from steaming up again?
After a hot shower, the mirror in my bathroom steams up. When I try to clear it with a towel, it immediately refogs. Yet once I use my hair-dryer, it will clear the fog and the mirror will stay clear.
...
0
votes
1answer
468 views
What makes water boil?
Basically how boiling takes place?
Also like to know...
What makes boiling point alter at various altitudes?
Why bubbles rise through boiling water?
1
vote
2answers
346 views
Why can't I evaporate water without wind, just heat? (not boiling,evaporating!) Or can I?
So here is the thing, I searched all over the internet for this but all the sources say that I need wind because the process of evaporation goes as follow:
Water particles at the top layer with ...
1
vote
3answers
132 views
Water, can it break through temperature?
If water is heaten up to ridicilously high temperatures, is it possible for the atoms in the molecules to lose their bonds?
And if it is possible, isn't this some kind of chain-reaction?
Like you ...
3
votes
1answer
426 views
Calculating time to heat cold water in bowl of hot water
How would I calculate the time it takes to heat a given volume of water to a given temperature with a given temperature T1 when it is submerged in a volume of water with a temperature T2
Estimation ...
8
votes
2answers
393 views
What is the status of Mpemba effect investigations?
There is this puzzling thing that is called Mpemba effect: paradoxically, warm (35°C) water freezes faster than cold (5°C) water. As a physisist, I've been asked about it several times already. And I ...
3
votes
1answer
186 views
Cause of sea ice freezing during an upwell event
One of the Episodes of BBC's documentary Frozen Planet describes an upwell phenomenon in the Antarctic Ocean. I am trying to understand the cause of seawater freezing when this upwell occurs.
Liquid ...
2
votes
1answer
701 views
Why did my frozen water bottle explode when I opened it after it defrosted a bit?
Last night I filled a 20 fl oz bottle (http://www.thenibble.com/reviews/main/beverages/soft-drinks/boylans-mash.asp) with lukewarm water from my tap. I filled the bottle pretty much to the brim, ...
3
votes
1answer
165 views
Boiling when I plunge my french press?
Occasionally when I make coffee in my french press I experience something odd. It happens pretty infrequently but certainly enough to be curious about. I have the grounds ready in the carafe. The ...
0
votes
1answer
2k views
Water Electrolysis Calculations
From Wikipedia (http://en.wikipedia.org/wiki/Water_electrolysis#Efficiency):
The electrolysis of water requires a minimum of 237.13 kJ of electrical energy input to dissociate each mole.
Each ...
1
vote
1answer
140 views
Calculating temperature of water in the freezer
Assuming water volume ($V$), initial water temperature ($T_0$) and environment temperature ($T_e$) are known, what is the easiest way to calculate temperature of water in given time ($T$)?
For the ...
6
votes
1answer
331 views
Microwave oven + water: dielectric heating or ion drag?
When you place a water or food in a microwave oven, it heats.
Which process commits more energy to that: dielectric heating, or ion drag i.e. resistive heating?
AFAIK, in distilled water (which is a ...
5
votes
4answers
619 views
Sauna thermodynamics
Why does it get hotter (feel hotter) in a sauna when one pours water over the hot stones?
Wikipedia says that the water condenses onto the skin, but the actual air humidity is so low that I doubt ...
4
votes
3answers
1k views
Why does hot oil explode when pouring water on it?
I am puzzled to know, What is the reason of hot oil make sound and explode when we pouring water on it?
9
votes
3answers
1k views
Thermodynamics of supercooled water
Now that it's been freezing outside for the last few days, I experimented a bit with supercooling. I've left a bottle of clean water outside for a few hours, and behold, when I shook the bottle, the ...
1
vote
1answer
495 views
How does liquid convert to gas on getting thermal heat energy?
Say for example, when we heat, water converts to steam gas. How does it happen? What happens underneath giving rise to breaking of bond between molecules in liquid state and spreading them in gas ...
3
votes
2answers
248 views
Will the water added to an ice piece freeze?
Water, at room temperature is poured into a hole made of a block of melting ice(kept at room temperature).I was wondering if the water will ever freeze?
Thank you.
2
votes
1answer
2k views
Best way to solve P-V-T Question
Typically in an exam or problem set we have a problem that's like this:
Determine the specified property at the indicated state of water. Locate the state on a sketch of the T-v and P-v diagram.
p= 3 ...
2
votes
1answer
833 views
Simple formula for liquid heat transfer
I'm trying to do a simple simulation of a solar panel coupled through some piping to a boiler, with the aid of a pump. My input constants could be something like: volume of liquid inside the panel, ...
2
votes
2answers
348 views
the form of a kettle
What is the best form for a kettle, that is, to have the water boil the fastest? I am particularly interested in the following case: for one given kettle (whose volume is constant) containing ...
0
votes
1answer
372 views
Uses and interpretation of the 'Bowen Ratio' ($B_o=SH/LE$)
The Bowen Ratio is the ratio of sensible heat flux to latent heat flux, so presumably it gives some information about the relative importance of these processes. But it is not clear how this ...
4
votes
1answer
1k views
Why is there more steam after a pot of water *stops* boiling?
I have a pot of vigorously boiling water on a gas stove. There's some steam, but not alot. When I turn off the gas, the boiling immediately subsides, and a huge waft of steam comes out. This is ...
2
votes
1answer
942 views
Do my noodles cook quicker when the water is boiling or when it is just about to boil?
I was just cooking some noodles and staring at the pot waiting for them to cook made me wonder... Will my food cook quicker when the water is boiling and bubbling, or when it is at a temperature where ...
4
votes
1answer
1k views
How cold does it need to be for spit to freeze before hitting the ground?
What is the dominant form of heat transfer between warm water and cold air?
If a $100 mg$ drop of water falls through $-40 C$ air, how quickly could it freeze?
Is it credible that in very cold ...
10
votes
4answers
5k views
Why does adding solutes to pure water lower the the specific heat?
We found that water with salt, sugar, or baking soda dissolved in it cools faster than pure water.
Water has a very high specific heat; how do these solutes lower it?
We heated a beaker (300ml) of ...
11
votes
3answers
895 views
A water drop in vacuum
Let's imagine the following situation:
At an initial moment $t=0$, a large water drop with diameter for example $D=10\ \text{cm}$ is placed in deep space (Say an astronaut is experimenting). Let's ...
4
votes
1answer
219 views
How to estimate condensation from air?
How to estimate the amount of water condensing from air on a surface, given the air's temperature and relative humidity and how they change over time, the surface temperature, material's thermal ...
