Some experiments answered basic questions about the universe while completely changing how humans understand the world.
1. The Cavendish Experiment Measured the Weight of Earth
In 1798, British scientist Henry Cavendish performed an experiment that measured the force of gravity between objects.
His work allowed scientists to calculate Earth’s density and estimate its mass, providing one of the first accurate measurements of our planet.
2. The Double-Slit Experiment Revealed Quantum Weirdness
First performed with light in the early 1800s, the double-slit experiment showed that tiny particles can behave like both waves and particles.
Later versions helped shape quantum physics and changed how scientists understand the behavior of matter at the smallest scales.
3. Rutherford’s Gold Foil Experiment Discovered the Atomic Nucleus
In 1909, Ernest Rutherford’s team fired particles at thin sheets of gold.
The unexpected results showed that atoms contain a tiny, dense nucleus, completely changing the previous understanding of atomic structure.
4. The Michelson-Morley Experiment Challenged the Idea of Space
In 1887, scientists Albert Michelson and Edward Morley tested whether a substance called “ether” carried light through space.
Their failure to detect it helped influence later developments in physics, including Einstein’s theory of relativity.
5. The Millikan Oil Drop Experiment Measured the Electron
Beginning in 1909, Robert Millikan used tiny oil droplets to measure the charge of an electron.
The experiment provided crucial evidence for understanding electricity, atoms, and modern electronics.
6. REM Sleep Research Changed How We Understand Dreams
In the 1950s, researchers discovered rapid eye movement (REM) sleep, a stage strongly linked with vivid dreaming.
The discovery transformed sleep science and showed that the sleeping brain remains highly active.