Science’s 10 Most Beautiful Experiments by George Johnson
Galileo’s experiment on falling objects
In the late 1500′s, everyone knew that heavy objects fall faster than lighter ones. After all, Aristotle had said so. That an ancient Greek scholar still held such sway was a sign of how far science had declined during the dark ages.
Galileo Galilei, who held a chair in mathematics at the University of Pisa, was impudent enough to question the common knowledge. The story has become part of the folklore of science: he is reputed to have dropped two different weights from the town’s Leaning Tower showing that they landed at the same time. His challenges to Aristotle may have cost Galileo his job, but he had demonstrated the importance of taking nature, not human authority, as the final arbiter in matters of science.
…
Young’s double-slit experiment applied to the interference of single electrons
Though it is not simply made of particles, neither can it be described purely as a wave. In the first five years of the 20th century, Max Planck and then Albert Einstein showed, respectively, that light is emitted and absorbed in packets — called photons. But other experiments continued to verify that light is also wavelike.
It took quantum theory, developed over the next few decades, to reconcile how both ideas could be true: photons and other subatomic particles — electrons, protons, and so forth — exhibit two complementary qualities; they are, as one physicist put it, ”wavicles.”
Eratosthenes’ measurement of the Earth’s circumference -the librarian at Alexandria in the third century B.C. estimated the circumference of the planet
Assuming the earth is spherical, its circumference spans 360 degrees. So if the two cities are seven degrees apart, that would constitute seven-360ths of the full circle — about one-fiftieth. Estimating from travel time that the towns were 5,000 ”stadia” apart, Eratosthenes concluded that the earth must be 50 times that size — 250,000 stadia in girth.
Related: Book, The Ten Most Beautiful Experiments by George Johnson (not the same experiments) – Home Experiments: Quantum Erasing – Particles and Waves – theory of knowledge – scientific experiments
More Mysterious Space Phenomenon
Posted on September 26, 2008 Comments (1)
One of the things I really hope this blog helps accomplish is to show how science progresses (which explains why I use that tag so often, 3rd most, other popular tags: animals (most used), engineers 2nd, fun and webcasts tied for 4th).
Science is a process of continual learning as curiosity leads us to seek better understanding. On a small scale this can mean a person learning more about knowledge already understood by others. But it also means the scientific community facing new questions and coming up with new explanations for the new questions raised by observations (and testing those new explanations…). Mysterious New ‘Dark Flow’ Discovered in Space
…
They discovered that the clusters were moving nearly 2 million mph (3.2 million kph) toward a region in the sky between the constellations of Centaurus and Vela. This motion is different from the outward expansion of the universe (which is accelerated by the force called dark energy).
“We found a very significant velocity, and furthermore, this velocity does not decrease with distance, as far as we can measure,” Kashlinsky told SPACE.com. “The matter in the observable universe just cannot produce the flow we measure.”
Related: Laws of Physics May Need a Revision – Great Physics Webcast Lectures – Challenging the Science Status Quo – Parasite Rex
Categories: Science, Students
Tags: commentary, cool, curiouscat, John Hunter, physics, scientific inquiry, space