There is a labeling plate on the microwave the specifies the frequency (~2.5ghz), and when you run it just long enough to begin melting spots of the chocolate bar, on older microwaves you can see several spots that are equidistant. Measure their separation (that's half the wavelength of the microwave), multiply by 2, multiply again by the frequency, and you have the speed of the wave.
It's poor precision (it is melted chocolate and depends on there being some standing waves, so older microwaves seem better suited) but accurate. And the math is pretty easy for kids, a ruler and a calculator.
That's just an excuse to do it a lot of times. :) Also a good segue into the story of the invention of the microwave oven: http://www.technologyreview.com/article/400335/melted-chocol...
The idea was that if anyone is ever going to "discover" new things in the future, they'll have to use out of the box thinking and measurement techniques to get there.
"The [experiment above] demonstrates universal gravitation with an apparatus which could have been conceived by Archimedes and built from materials he could readily obtain [during the time Archimedes lived 2200 years ago]."
Anyway, I thought the deviation of the string was done by Cavendish in his basement to find the gravitational constant.
The mass of a celestial object can be acquired by measuring the period of one of its satellites, which conveniently the Earth has naturally.
I did a speed of light measurement in high school physics. We had a prism mirror on a 30,000 RPM motor, a slit lamp (not a laser) and some mirrors. The narrow bar of light from the slit lamp was aimed at the prism, which reflected the light to a distant mirror, then back to the prism, then onto a target. The idea is that as the motor RPM increases, the line of light projected onto the target will move slightly, and you can calculate the speed of light from this.
We didn't have a dark enough or long enough room, and aligning all the mirrors was a huge pain. We could see the line of light move slightly as the motor speed increased, but our baseline was too short to get enough movement to measure accurately.
> Beeckman understood that, lacking lasers, the basis of any good scientific experiment should always involve explosions of some kind; thus, his experiment involved detonating gunpowder.
Incidentally, it's quite interesting to me that the most accurate measurements of c are actually indirect measurements. See https://en.wikipedia.org/wiki/Speed_of_light
If you want your mind blown, there also was a physicist in the 20th century who questioned whether or not the speed of light was directionally invariant (isotropic). So the speed of light going one way versus the other might be different. This results in a different set of transformations, the Tangherlini transformations, that govern the structure of spacetime.
Starting about halfway the page from "DEMONSTRATION TOUCHANT LE mouvement de la lumiere"
Specifically, I'm interested in learning how big IO and Jupiter looked to him. I've looked up at Jupiter and Saturn etc. a few times through science class telescopes, never been able to see the moons.
That's some good thinking in that time... any idea what could have made them suspect this back then? There were hardly even newtonean physics, and you can't see with the naked eye that it's a finite speed, so I'd love to know how they reasoned aobut it.
Aside from the debate over whether the speed of light
was infinite or not, a common side debate throughout
history was whether or not light originated in the eye
itself or from something else. Among the famous
scientists to believe in the “light emitted from the
eye” theory were Ptolemy and Euclid. Most who thought
this theory correct also thought the speed of light must
be infinite, because the instant we open our eyes, we
can see a vast number of stars in the night sky and that
number does not increase the longer we look, unless of
course we were previously looking at a bright light and
our eyes are adjusting to darkness.
It would be essentially ray tracing. "Light", from our eye, travels though stuff and ends up colliding with an object. We are informed of how the ray was affected and how it collided, perhaps because the ray is an extension of our perception (like a limb of sorts), or perhaps because the final collision always causes it to go back exactly the way it came.
It's simpler and more obvious than the idea that there exists a truly massive amount of light emitted though various processes in nature, most of it never perceived by any eye, and the minuscule sample caught by our pupil is still large enough to provide us with so much detail. In the absence of further knowledge on the subject you're studying, Occam's razor can easily mislead.
But certainly there was no reason for any serious historical thinkers to speculate along such lines.
That was the beginning of the science. People had just started to question everything they knew, and discovered almost all of it was wrong. And good scientists keep assumptions at check anyway, even now that we have so much evidence.
I guess they could have argued that the rays of light returning from each object were perfect specular reflections that traveled directly back to the eyes that emitted them... but wow, that's still pretty hard to fathom, even for people who never heard of Occam's Razor.