Atlas Trail
How We Know: Five Experiments That Settled a Question
How does anyone actually know what they claim to know. This trail follows five experiments where a careful test settled a real question or overturned an assumption science had been carrying: a search for motion through empty space that found nothing, a beam of particles that bounced back when nothing should have, a total eclipse used to weigh starlight against a brand new theory, a pattern that only makes sense if a particle can be in two places at once, and a single photograph that showed the shape of the molecule carrying heredity itself.
Stop 1 of 5.
Experiments
A meticulous null result. Two American scientists built the most sensitive light experiment of their era to detect the motion of the Earth through a hypothesized medium called the aether, and found nothing, a result at least as important as a positive one would have been.
Stop 2 of 5.
Experiments
A result nobody expected. Firing particles at a thin sheet of gold foil, Ernest Rutherford found that a few bounced straight back, evidence that the atom carries a small, dense, positively charged core rather than being a uniform blob of charge.
Stop 3 of 5.
Experiments
A prediction tested against the sky. A total solar eclipse let astronomers photograph stars near the edge of the Sun and measure how far their apparent positions shifted, a real time check of a brand new theory, general relativity, against the world.
Stop 4 of 5.
Experiments
A pattern that should not be there. Sending particles through two slits produces an interference pattern that only makes sense if each particle behaves like a wave passing through both slits at once, one of the cleanest demonstrations of quantum mechanics.
Stop 5 of 5.
Experiments
A single photograph that showed a shape. An X-ray diffraction image made the helical structure of DNA visible for the first time, evidence that shaped the double helix model published soon after.
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