Tagged Questions
4
votes
0answers
75 views
Mechanical Equivalent of Heat
Recently I have been looking up James Joule's experiment regarding the mechanical equivalent of heat. After viewing some drawings of the apparatus, I assumed that the lines holding the weights would ...
5
votes
3answers
223 views
How can I determine the coefficient $k$ in $ \dfrac{dT}{dt} = -k(T - 100 \mathrm{^\circ C}) $?
I recently spend some time on cooking and I'm curious about the time evolution of the temperature of the water. I did some experiment and the temperature is of the form
$$ T = 100 \mathrm{^\circ C} + ...
8
votes
3answers
527 views
How hot is the water in the pot?
Question: How hot is the water in the pot? More precisely speaking, how can I get a temperature of the water as a function of time a priori?
Background & My attempt: Recently I started spend ...
0
votes
1answer
145 views
Best way to move teaspoon to dissolve sugar in a cup of tea
I know that there is asked questions about something like cooling down cope of coffee..etc, but this one is little different.
My friend was watching TV program of English eating etiquette, and they ...
5
votes
3answers
207 views
experimental technique for measuring temperature of an ant
I am taking a course on thermodynamics. I have a question from my text(halliday & resnick,physics-1). They asked me to measure temperature of an ant or an insect or a small body,like a small ...
1
vote
2answers
156 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.
...
1
vote
1answer
117 views
Calibrating an electronic temperature sensor based on power consumption
I'm working with an electronic temperature logger that is being affected by heat generated internally.
How does one come up with a calibration equation to calculate a more accurate reading of ambient ...
1
vote
5answers
170 views
Normal distribution of x, xdot
I have some real measurements from a process and I happened to look at the mutual distribution of (x(t), xdot(t)). I found that they seem to follow 2d normal distribution around (mu, 0). See image, ...
2
votes
2answers
683 views
Testing the temperature of an open flame
How, and what device do you need, to obtain the exact temperature of an open flame? For the purpose of this question, you wanted to maintain 375 degrees. You can control the flame, but have no idea ...
1
vote
1answer
151 views
Depalma Free Energy fields
Few years ago I read some papers about Free Energy, written by Bruce de Palma, a physicist who is said to be the inventor of the N-Machine, which is an device that works with free energy latent in the ...
4
votes
2answers
299 views
What are the easiest to get/make LN2 superconductors?
I am starting to build multistage Peltier cooler at the moment, and it should be able to reach -100C at least (but if I fail I can always get boring LN2).
Doing some experiments with superconductors ...
7
votes
6answers
3k views
Explanation of “thermite vs ice” explosion
There are several videos of the reaction, where some amount of burning thermite explodes on a contact with ice.
An "original" video: http://www.youtube.com/watch?v=IuPjlYxUWc8
A Mythbusters ...
161
votes
19answers
55k views
Cooling a cup of coffee with help of a spoon
During the breakfast with my colleagues, a question popped into my head:
What is the fastest method to cool a cup of coffee, if your only available instrument is a spoon?
A qualitative answer would ...
5
votes
2answers
442 views
Experiments that measure the time a gas takes to reach equilibrium
If you take two ideal gases at different temperatures, and allow them to share energy through heat, they'll eventually reach a thermodynamic equilibrium state that has higher entropy than the ...
