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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
It's approximately 300 000 km/h. 'Nuff said.
Or even, what's this thing called "leftover chocolate?"
That was two days ago. Give us some pancake science!
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
I'm pretty sure I read about girlfriends in Popular Science...
I wonder if this works with that nasty fake stuff that Palmer makes. You know the stuff, made with vegetable oil instead of cocoa butter, and labelled "Milk Chocolate flavored candy"? It may change the melting dynamics just enough to invalidate the whole experiment. I bet that stuff isn't even good enough for science experiments.
Is this what Dr. Sheldon Lee Cooper do on Valentines Day?
> Now I'm hungry.
Now I am *horny*. There must still be hope in my case...
Everything I write is lies, read between the lines.
Not what I would call completely transparent, eh?
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
While I have some Valentines chocolate remaining uneaten, none of it is 'left over'.
It's far too valuable to melt (thus destroying many of it's finer qualities), a) because it's quality chocolate rather than crap picked up at the convenience store, and b) my wife handpicked the assortment for me catering to my tastes.
alas, if only most slashdotters were in Japan. There the women or girls give low cost chocolate to all the guys at work or in school class. It's called "obligation chocolate" or "pity chocolate", but if there is a guy they really like they give expensive or homemade chocolate with a gift "prospective winner chocolate".
So no male is without cheap chocolate from a female, at least.
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".
I should have specified that I have a groovy orgy an every Valentine's day.
Did you miss the fact that we were talking about "Valentine's day" chocolates ?
Everything I write is lies, read between the lines.
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!
False. Disproved by direct observation. Stand on a pier sometime and look at the waves. The spot where a maximal low is does not become the maximal high; instead a spot in front of it is the maximal high. There is, indeed, a rolling forward effect.
Just because there are microwaves of different size does not mean that none of them were designed to produce heat lines. It's about multiples of the wavelength, not absolute size, anyway. Ever wonder why we can see many buildings that express the golden ratio, but they are not all the same size?
"Trolls they were, but filled with the evil will of their master: a fell race..." -- J.R.R. Tolkien on Olog-hai
They're no longer "ocean waves" at that point. In the mid-atlantic or mid-pacific the water stays in place.
That is normally listed on the back of the microwave, and is almost always in the 2.4GHz range. You also don't need the figure that precise, given that your result is basically likely to have only about 1 sig fig anyhow. That's fine, since light is extremely close to 300,000,000 m/s. You need 4 sig figs before a discrepancy starts to show up, and you aren't getting that out of an experiment like this.
Nobody is claiming this is USEFUL, like you are finding out something amazing. After all, we know the speed of light to 9 figures already. This is just a fun type of experiment to show someone the practical application of wave related calculations. You could also run it the other way and calculate the frequency based on the measured wave length and known speed if you like.
Basic science experiments are always rather worthless in terms of true scientific knowledge. They don't tell you anything you couldn't look up. What they are worth while is in terms of personal knowledge. They show people how science work, they show them that these formulas don't come from nowhere, that they work on real, actual data.
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!
The matter stays in place, but the wave energy passes on continuously. In a standing wave, the nodes are fixed. This is not the case in the ocean.
Yes it's an anecdote! Were you expecting original research in a Slashdot comment?
The fastest rate your girlfriend can cram them into her mouth when she doesn't think you're looking.
I swear to God...I swear to God! That is NOT how you treat your human!
Though as far as I'm concerned it's cheating looking up the frequency of the microwave. It should be measured, which isn't as easy.
If only Ole Rømer had had a microwave oven ;-)
These posts express my own personal views, not those of my employer
It's a neat trick, albeit an old one. But it's not quite a real measurement of C. The problem is that you're given the frequency to start with, and a smart high school student will tell you that means you also know the wavelength. So if you trust the frequency rating of the microwave then the only thing you're really doing is verifying that the ruler you're using is accurate.
Building Better Software
She. Her name is Kathy Ceceri. She's a she, not a he.
"Fish" (David B. Trout)
My bad, I didn't read the byline. I assumed that an article on a blog called GeekDad was written by a geeky dad... ;-)
Write your representatives! Repeal the 2nd Law of Thermodynamics!
In light of your sig, the rest of your post is actually quite funny ;)
MCSE? No, sir...I don't do Windows. Yes, I am an idealist. What's your point?
"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
In light of your sig, I hope you do not live in South Korea ;-))
Everything I write is lies, read between the lines.
... but those chocolates did disappear pretty darn fast at our house.
#DeleteChrome
You mean like, both hands at once?
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.
Ah. That explains it all.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
If you're like the average slashdotter, there would be a lot more hope for you if you were just hungry... unless you've got an "American Pie" like fetish for warm chocolates!
I've abandoned my search for truth; now I'm just looking for some useful delusions.
Is that why you can't hear anything except when there's a wind blowing?
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
Yep, I seem to remember that the girls both used their hands at once at some point...
Everything I write is lies, read between the lines.
> If you're like the average slashdotter
Without regards for the groups I might be considered part of, I am never considered "average" in any case.
Everything I write is lies, read between the lines.
400-790 THz
In terms of frequency, this corresponds to a band in the vicinity of 790-400 terahertz.
http://en.wikipedia.org/wiki/Visible_light
Saw this some years back on the Christmas Lectures that the Beeb run... They did it wih a tray of marshmallows... Can't find a link to that though, but did find this one: http://www.physics.umd.edu/ripe/icpe/newsletters/n34/marshmal.htm
This is a pretty crappy experiment. I've done this before, but covered the bottom of my microwave with water soaked sheets of paper (which allows a constant height and full coverege) instead of chocolate. You do get a number of hot spots (where the paper completely dries), but they appear to be randomly spaced. The only way this experiment "works" is when you identify two spots that happen to be somewhat close to 12.5 cm apart (the value you're expecting -- 3e8/2.4e9) and ignore all of the other possible spacings. Microwave propagation in a microwave oven isn't nearly as simplistic as this experiment would require.
He may mean leftover chocolate boxes, I have plenty of those.
All further computations shall be done by judges and attorneys, but you'll have lots of time to spare for writing great code afterwards.
BTW, the safety instructions miss the warning:
Remove all items such as knives, forks and frying pans she might feel an impulse to stab or hit you in the head with..."
Not all microwave ovens have the rotating reflector thing. In fact most of them (especially modern ones) are too cheap to include such a component and they just spin the food around in the hopes of avoiding hot spots. Remove the rotating glass plate on a cheap oven and you'll get perfectly defined hot and cold spots.
Is that what you'd use to cook a spherical cow in?
> While it may be conceivable to create a 'perfect' microwave with no standing wave nodes, it would be pointless.
I see what you did there...
actually, the top of line is considered to be home-made chocolate, which can be made by cheating a bit with cheap candy bar, melted and a couple ingredients added to kick up a notch. So hand effort makes the supreme valentines day gift, within reach of the poor for their special someone.