Quick! Calculating the speed of light!

Author: ilamandarina in Uncategorized on October 23, 2008 | 8 comments

I recently received email from a friend ... in which I explained frankly amazing experiment. How to calculate the speed of light with a jelly bean and a microwave.

Believing that experience is very interesting, I thought I should give you the details ... Let's do this!

First, get a jelly bean of these elongated and preferably red. Then immobilize the turntable of the microwave where we would set ends with tape or gummy adhesive tape, so it is parallel to the door of the microwave. Close the door and connect, making it operate at low power (approximately 200 Watts). Maybe we get to do some testing time and power to achieve optimum results ...

After a while, we see that the jelly begins to acquire the waveform, with "peaks" and "valleys". The crests rise and are areas that tend to "burn". The valleys, however, remain unchanged. Before we run out of jelly ... The microwave will we!

With the help of a ruler, measure the distance between two consecutive valleys, which will surely be the order of several centimeters. Then we will look at the microwave frequency in the board of technical specifications, which will probably be a few hundred megahertz.

Finally, it was time for math! If we multiply the distance between two valleys, we obtain the wavelength, ie, the wavelength of light in cm, we can pass am simply dividing by 100 the number obtained. In this result we multiply the microwave frequency in megahertz, but we get by dividing Hertz 1000000, if you want to work in the correct units ...

And ... presto!! What appears? The speed of light!

If you have made appropriate changes in units: a meters and Hertz, you will get the speed of light in m / s ... If not, the units are cm / Megahertz ... but it should not worry too much ...

The explanation is simple: the microwave is a resonant cavity where standing waves are formed, and which have a maximum (bellies) and minimum (nodes). Where to get a belly, jelly burn in and up. Where it touches a node, the microwaves do not heat it, therefore, the gummy remains intact, are the valleys that you have observed. The distance between two consecutive valleys multiplied by two, corresponding to the wavelength of the microwave. Multiplying the wavelength (meters) times frequency (s-1) we obtain the velocity (m / s) propagation of the wave of the microwave, ie, infrared light ... In the light traveling in the air ... The famous "c"! Cool!

This and other curiosities of the book you can find in Log Feature, browse multiple universes, David Barrado, Benjamin Montesinos and you will find in the library Laie .

8 Responses to "Quick! Calculating the speed of light! "

Victor says:
October 23, 2008 at 17:44
A bon em meu amic professor will discuss a fer-ho vegada amb one, or one month d'"tranchetes" surface dyeing month. On the interference was constructive quedaven recremades frange. S'haurà provide ....
Salut!
Victor
dt says:
October 23, 2008 at 19:33

Wow! semblat m'ha interessant molt! Aquest plantejat Mai m'havia not experiment ... If aixequès Michaelson Chapter ...
Victor, et dec a trick, not pas your oblidat m'he!
Salut!
ilamandarina says:
October 23, 2008 at 19:37
Doncs sabeu ja, ia the cuina experience! That's Tractatus d'això!
Prova amb is diferents Tipus pot of llaminadures i have anat Despres millor quines comentem. proposava jo that they are a month mica llargues that els "tranchetes" but tense Rao menys holdings surface ...
Be, he said, hands-on science!
Als Records two!
ilamandarina
Jordi says:
October 24th, 2008 at 10:23
Bona dels idea "tranchetes." We will give molt month probablement them easily measurable distances between zones i Cremades / or recremades, month compte tenint in the major area. Aquest is xulo molt experiment, but efectiu senzill! Crec it would be a bona molt per estudiants practice of batxillerat.
Salut!
Salva says:
October 28th, 2008 at 20:43
A interessant força experiment, but ja llum velocitat of the Dur-Abansa conexíem to terme it, no?
Hahahaha!
Molten pel felicitats blog. Em Sembler great, i tot that saps that ho ja Aviat of Arts sóc month.
A abraçar
ilamandarina says:
October 28th, 2008 at 21:53
Save Ei!
Il · lus Quina group that t'uneixis "científics disquiciadors."
Això think motivates em on capibares Escrits nous to velocitats incalculable!
A bib!
ilamandarina
Raul says:
October 31, 2008 at 12:15
Flipante Estic!
For what we want then the LHC, if we can trace the origin of the universe with a microwave and a package of peta zetas?
ilamandarina says:
October 31, 2008 at 15:41
No man, no!
With the microwave and jellies calculate the speed of light, c, 300.000km / s.
The LHC gets a lot more. They accelerate protons and heavy nuclei at speeds close to those 300.000km/si make them crash and look what happens ...
But this, you gave me an idea!
The next writing ... the LHC!
Also this week just to deliver a paper on the UPC accelerators Press.
Promised!
Quick kiss!
ila

about me

I'm Irene, mandarin ila, curious and playful, who would like to understand why almost all things and the origins of the universe. Live fascinated by art, dance, shapes and colors. One day I felt certain that for me the science and art combined in disclosure. That day I chose to work as a journalist and science writer.
A little over a year Newton was born Tangerine as a blog. Its origin was in blogspot .
In 2010, tangerine moved to Wordpress and its timid beginnings are transformed into a business venture.
The Tangerine Newton is a project that combines science and technology with any other discipline, to create activities, exhibitions, meetings, and educational playthings. You can find more information on the web or follow each month on the podcast of science in Catalan of the Irene Newton Tangerine Tomàs Lapuente and Manzanares.