New answers tagged home-experiment
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The idea of using soot sounds like something people did in the 19th century and that everyone then kept describing the same way as a matter of tradition. I've done this successfully by (IIRC) filling in some area of a plastic transparency sheet with a Sharpie, then scraping off the slit pattern I wanted.
Calculate the pattern you expect, so that you have ...
9
Of course it has something to do with the liquid water entering the gas phase just above the cup of tea, but how does that give the bag of tea a directed motion to one side?
Nope.
The teabag is dangled by a string. Remember that the string is made of wound up threads:
Now, the threads stay wound up because they fit well and they have a knack of ...
1
I do believe that yes. The most hard part will be to obtain the materials.
If you manage to get a good piece of n-type (or p-type) Silicon, big enough to allow you to work with home tools, you'll "just" have to do local oxidation (with temperature for example) and make some soldering.
Of course, the quality of that transistor would be very doubtful as it ...
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The easiest method is to put a magnetic compass on one of the magnet's axes of symmetry, and orient the compass and magnet such that the magnet's field is perpendicular to the earth's. Then the tangent of the deflection angle is equal to the ratio of the fields.
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see we use simple integration ..
$$dT/dt = -k(T - 100)$$
this is in accordance with Newtons Law Of Cooling which says that the negative rate of change of temperature is directly proportional to the difference of the initial temperature of the substance and the surrounding temperature of the environment.
$$dT/dt = -k(T- 100)$$
$$dT/(T- 100) = -k \,dt$$
...
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The short answer is they don't cool nearly as well as ice
The harvard food and science team did an experiment for this exact scenario. The results were:
As the ice melts it drops the temperature of Whiskey to nearly -4C, where as the whiskey stones barely got the drink close to zero.
The reason has already been explained nicely in Manishearth's answer.
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TL;DR: Whiskey stones work by absorbing heat from the whiskey in an attempt to reach thermal equilibrium1.
As Thomas mentioned, ice has three cooling effects:
Ice itself takes 2.11 kilojoules of heat per g to have its temperature increased by 1 degree (Celsius). This number is known as "specific heat capacity"
Ice takes 334 kilojoules of heat per kg at 0 ...
5
Whiskey stones aren't necessarily designed to keep the drink cold, instead they are designed to allow flavor profiles to come out in the drink that might not be present at room temperature. Some whiskeys open up at a slightly cooler temperature and using stones allows you to experiment without diluting the flavor of the beverage. There are better math ...
47
Ice cubes have three distinct cooling effects:
The cube, initially at sub-zero temperature, absorbs some heat to reach fusion point (0⁰C).
The cube absorbs more heat to switch phase: it takes some energy to turn 1 kg of ice at 0⁰C into 1 kg of liquid water at 0⁰C.
The water absorbs some heat to become warmer than 0⁰C.
The three effects occur more or less ...
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A fundamental principle of thermodynamics is that heat flows from warm places to cold ones, through either convection, conduction or radiation, and it will continue to do so until the temperature equalizes across the system.
The stones are colder than the whiskey when you put them in the glass, so as the system heads towards equilibrium, the whiskey gets ...
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The Wikipedia quote you are referring to is:
Sometimes, microwave heating is explained as a resonance of water molecules, but this is incorrect;[11] such resonances occur only at above 1 terahertz (THz).
The source cited is:
Schmitt, Ron (2002). Electromagnetics Explained: a handbook for wireless/RF, EMC, and high-speed electronics. Burlington, MA, ...
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A vertical sundial that doesn't face N, E, S, or W is called a vertical declining dial. Formulae are in the link.
I don't know if, for such dials, there is any inherent difficulty with Babylonian or Italian hours. Ask Frank King.
By the way, there is a staggering amount of information on sundials available on the Internet. One may start with the Wikipedia ...
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The questioner says that he once heard a Frank King talk and then asks about designing a sundial that indicates Babylonian Hours and Italian Hours when the dial doesn't face due south. The sundial that was the subject of Frank King's talk doesn't face due south either. I suggest the questioner gets in touch with Frank King who might be able to advise.
...
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We did this experiment in my undergraduate physics class. Search for "Michelson-Morley experiment classroom" and you will find products such as this: http://i-fiberoptics.com/laser_detail.php?id=2120
Before the advent of lasers with a visible beam, the alignment of interferometer components was very difficult to achieve under ordinary laboratory ...
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