Slashdot Mirror
Measuring the Speed of Light With Valentine's Day Chocolate
Cytotoxic writes "What to do with all of those leftover Valentine's Day chocolates? — a common problem for the Slashdot crowd. The folks over at Wired magazine have an answer for you in a nice article showing how to measure the speed of light with a microwave and some chocolate. A simple yet surprisingly accurate method that can be used to introduce the scientific method to children and others in need of a scientific education."
although its far more interesting to use chocolate to measure the speed of digestion
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Or even, what's this thing called "leftover chocolate?"
That was two days ago. Give us some pancake science!
299792458 m/s, to be exact.
The Tao of math: The numbers you can count are not the real numbers.
I think you mean approximately 300 000 km/s, not km/h. You're only out by a factor of 3600, no worries!
Modding "-1, Troll" is not a proper response if you disagree with me. Try reason.
Are you sure? My Texas School Board Approved textbook says the speed of light is exactly the speed it takes God to wink. Coincidence? I think not.
This experiment has lots of problems. *nom nom nom* First, microwave ovens don't always precisely match the given frequency. *chomp chomp* Second, and more importantly -- *chew chew swallow* -- identifying the hotspots and measuring the distance between them is difficult and error prone. *nom nom* And that's even when the chocolate is fresh! It's worse after it's already been partially melted. *stuff face* So I had to perform many experiments, using fresh chocolate each time, to get an accurate measurement.
In conclusion, this experiment rules. *nom nom nom nom*
The enemies of Democracy are
Is this what Dr. Sheldon Lee Cooper do on Valentines Day?
If a microwave, chocolate, and performing an experiment make you horny...
Let's just hope you never learn what fondue is.
"Trolls they were, but filled with the evil will of their master: a fell race..." -- J.R.R. Tolkien on Olog-hai
God takes speed to wink... :|
Always back up, never back down. ---- Think you're cool 'cos your uid is prime? Take mine, modulo the one digit integers
Now this is very informative ;-)
Actually, not that much since you did not specify in which environment it has that "exact speed". Saying the speed of light is 194792442 m/s or any value is just as precise.
Now, saying that c is constant equal to 299792458 m/s is absolutely correct although, the speed of light is actually:
c/n where n is the refraction index.
In a microwave oven at sea level, the speed of light is *approximately* 299792458/1.0003 = 299702547 m/s
Everything I write is lies, read between the lines.
See: Modern myths.
There are only two places in the entire planet where there's a chance of finding "Leftover chocolate."
Aslo, the article is wrong:
Ocean waves don't "move forward".
Disproved by direct observation. Go into any store and you'll see microwaves in various sizes. The perfect microwave doesn't have "hot spots".
Aslo, the article is wrong:
The demonstration works because microwave ovens produce standing waves -- waves that move "up" and "down" in place, instead of rolling forward like waves in the ocean.
Ocean waves don't "move forward".
While the individual particles do not, the wave itself does.
He is mistaken on the meaning of a standing wave. It is not the same as a transverse wave (which seems to be why he is comparing them to a longitudinal wave).
The oven is designed to be just the right size to cause the microwaves to reflect off the walls so that the peaks and valleys line up perfectly, creating "hot spots" (actually, lines of heat).
Disproved by direct observation. Go into any store and you'll see microwaves in various sizes. The perfect microwave doesn't have "hot spots".
Again, he's wrong about it being 'designed' for the purpose of having hot spots, but the design does result in hot spots. These occur regardless of oven size, they will simply be located in different locations. This is caused by reflections off internal surfaces acting like two signal sources.
While it may be conceivable to create a 'perfect' microwave with no standing wave nodes, it would be pointless. Besides, he wasn't using an 'ideal' microwave, just a regular off-the-shelf microwave, which does have standing waves.
Write your representatives! Repeal the 2nd Law of Thermodynamics!
Now this is very informative ;-)
Actually, not that much since you did not specify in which environment it has that "exact speed". Saying the speed of light is 194792442 m/s or any value is just as precise.
Now, saying that c is constant equal to 299792458 m/s is absolutely correct although, the speed of light is actually:
c/n where n is the refraction index.
In a microwave oven at sea level, the speed of light is *approximately* 299792458/1.0003 = 299702547 m/s
Nerd
It's stated on the microwave (or in its documentation). They don't get that by knowing the speed of light, but rather by the construction of the device. You could build your own microwave generator to be sure, but assuming that the manufacturer is giving you the correct value is good for an estimate.
OK, so you get the wavelength from the melted chocolate hot spots, but what's an easy way to verify that the frequency is really 2,450,000,000 hertz, from first principles?
Spin the turntable at 2,450,000,000 revolutions per second and look for stroboscopic effects on the chocolate?
"How to Do Nothing," kids activities, back in print!
> Nerd.
Actually, using expression like "approximately" or specifying an error margin instead of using terms like "exact" like the GGP did is a pretty scientific standard and it is overall a good habit in all sphere of life.
In general, one should be doubtful about "absolute truths", "exact calculations", "100% efficiency" or the like ;-))
Everything I write is lies, read between the lines.
She. Her name is Kathy Ceceri. She's a she, not a he.
"Fish" (David B. Trout)
Except that the speed of light in vacuum is exactly 299792458 m/s. Not approximately, exactly. By definition (of the meter).
The Tao of math: The numbers you can count are not the real numbers.
"Valentine's Day chocolates? a common problem for the Slashdot crowd."
What is this Valentines Day? What does it have to with chocolate? ?
I think your new here, as that not on the list of IT holidays...
And there is NEVER left over chocolate, err.. REAL chocolate.. not that crap Hershey stuff (AND NO I don't buy Cadbury in the US! I know its licensed to be made by Hershey.. I have importers bring in the REAL CADBURYS!)
Just like beer if its made in the US, its junk. Same goes for chocolate.
Want cheap chocoloate, purchase all the Hershey you want.
1311393600 - Back to Black
Actually, it is measuring the wavelength of the microwave radiation, and assuming the stated frequency is correct, calculating the speed of light from that. However, this is circular, sense the frequency was most likely also calculated by measuring the wavelength!
I've abandoned my search for truth; now I'm just looking for some useful delusions.
Anything else I can do for you today ? My car _really_ needs to be washed... and it would also be nice if you could give the interior a "once over" with a perfect vacuum.
I've abandoned my search for truth; now I'm just looking for some useful delusions.
A smart high school student will tell you that you can only calculate the wavelength from the frequency if you already know the speed of light (the formula is C = Wavelength x Frequency).
Why would anyone engrave "Elbereth"?