33 Physics Experiments That Changed Our Understanding of the World

Throughout history, amazing physics experiments have shaped our ideas about everything from gravity to light. These experiments challenge what we think we know and open our eyes to the mysteries of the world. 

Each experiment, whether big or small, has given us new insights into the world around us and the laws that govern it.

1. The Law of Gravity (Isaac Newton, 1687)

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Do you know why things fall to the ground when you drop them? Isaac Newton figured that out back in 1687. He realized that everything with mass, like the Earth, pulls on other things with mass. 

This pull is what we call gravity. Newton’s “law of gravity” explains why apples fall from trees and why the moon orbits the Earth. It’s one of the most famous scientific discoveries, and it helped us understand how the universe works.

2. Einstein’s Theory Confirmed by a Solar Eclipse (Albert Einstein, 1919)

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In 1919, Albert Einstein’s mind-blowing theory of relativity got its big break during a solar eclipse. He predicted that light from distant stars would bend when it passed near the sun due to the sun’s gravity. 

Scientists, led by Sir Arthur Eddington, confirmed this by observing stars during the eclipse, and it proved Einstein right. This discovery made Einstein world-famous and changed how we understand space, time, and gravity.

3. The Existence of the Electron (J.J. Thomson, 1897)

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Imagine discovering a tiny particle that’s part of every atom. That’s what J.J. Thomson did in 1897 when he found the electron.

Electrons are negatively charged particles that zip around the nucleus of an atom.

This discovery completely changed how we think about the structure of matter and was the first step toward understanding things at the atomic level.

4. Calculating the Charge of an Electron (Robert Millikan, 1909)

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After J.J. Thomson discovered the electron, scientists still needed to figure out how much charge it had. In 1909, Robert Millikan did just that with his famous oil-drop experiment. 

He suspended tiny droplets of oil between two metal plates and measured how the charge on the droplets changed. From this, he figured out the exact charge of a single electron.

It was a huge step in understanding the building blocks of matter.

5. The Discovery of Electrical Phenomena (Michael Faraday, 1831)

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Before the modern world of electricity, there was Michael Faraday, who in 1831 discovered “electromagnetic induction.” He found that if you move a magnet through a coil of wire, it creates an electric current. 

This was a huge discovery because it led to the development of electric generators, which power so much of our technology today. Faraday’s discovery is one of the reasons we have electricity in our homes.

6. The Overthrow of the Heliocentric Model (Galileo Galilei, 1610)

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For centuries, people believed that the Earth was at the center of the universe. Then, in 1610, Galileo Galilei looked through his telescope and saw that this wasn’t true.

He noticed moons orbiting Jupiter, proving that not everything revolves around the Earth. 

This was important because it supported the idea that the sun, not the Earth, is the center of our solar system. This discovery helped change how people viewed the universe forever.

7. Law of Energy Conservation (James Prescott Joule, 1843)

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In 1843, James Prescott Joule showed that energy doesn’t just disappear or come from nowhere—it’s always conserved. This means energy can change forms, like from heat to motion, but the total amount stays the same. 

This law of energy conservation is a key idea in physics, and it helps explain everything from engines to the way the universe works.

8. Initiation of Nuclear Chain Reactions (Enrico Fermi, 1942)

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In 1942, Enrico Fermi and his team achieved the first controlled nuclear chain reaction. This experiment, conducted in a lab under a stadium at the University of Chicago, led to nuclear power and nuclear weapons. 

It worked by splitting atoms, which released a huge amount of energy. Fermi’s work marked the start of the nuclear age, with massive consequences for both energy production and warfare.

9. Revelation of Black Holes (Karl Schwarzschild, 1916)

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Black holes might seem like something from a sci-fi movie, but they’re real! In 1916, Karl Schwarzschild was the first to propose the idea of a black hole while working on Einstein’s theory of relativity. 

A black hole is a place in space where gravity is so strong that nothing, not even light, can escape. This discovery helped scientists understand more about how massive stars collapse and what happens in extreme environments in space.

10. The Gold Foil Experiment: Atom Structure (Ernest Rutherford, 1909)

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Imagine shooting tiny particles at a thin sheet of gold. That’s what Ernest Rutherford did in 1909, and what he discovered changed everything we know about atoms. Some particles bounced back, which was totally unexpected. 

This led Rutherford to realize that atoms have a small, dense center, called the nucleus, surrounded by mostly empty space. Before this, people thought atoms were solid balls.

Thanks to Rutherford, we now understand that atoms have a complex inner structure.

11. Wave-Particle Duality Phenomenon (Albert Einstein, 1905 & Louis de Broglie, 1924)

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Does light behave like a wave or a particle? The answer is both! In 1905, Einstein showed that light could act like tiny particles called photons. Then, in 1924, Louis de Broglie suggested that even particles like electrons could behave like waves. 

This is called wave-particle duality, and it’s one of the weirdest but most important ideas in quantum physics. It shows us that at the smallest scales, the rules of physics are different from what we experience every day.

12. Separation of White Light into Spectral Colors (Isaac Newton, 1665)

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In 1665, Isaac Newton took a simple glass prism and made an amazing discovery. When he passed white light through the prism, it split into all the colors of the rainbow. 

This experiment showed that white light is made up of many different colors. Newton’s discovery helped us understand more about light and color and laid the foundation for modern optics.

13. Study of Blackbody Radiation (Max Planck, 1900)

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Max Planck made a huge discovery while studying something called blackbody radiation, which is the type of energy objects give off when they are heated. Planck found that energy is released in tiny packets called “quanta,” instead of being continuous. 

This was the start of quantum theory, a field of physics that would later change how we understand everything from atoms to the universe.

14. The Discovery of the Higgs Boson (Peter Higgs, 1964 & CERN, 2012)

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The Higgs boson, sometimes called the “God particle,” was first proposed by Peter Higgs in 1964. This particle explains why other particles have mass, which is a pretty big deal. 

It wasn’t until 2012, though, that scientists at European Organization for Nuclear Research (CERN) finally detected the Higgs boson using the Large Hadron Collider, the world’s biggest particle accelerator. This discovery confirmed a key part of how we understand the universe, filling in a missing piece of the puzzle in the Standard Model of particle physics. 

15. Measuring the Earth’s Mass (Henry Cavendish, 1798)

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In 1798, Henry Cavendish found a clever way to measure it. He used a setup called the Cavendish experiment, which involved two small lead balls being attracted to two larger lead balls by gravity. 

By measuring this attraction, Cavendish could figure out the mass of the Earth! His experiment was so precise, it’s still considered an incredible feat of physics.

16. Principle of Mass Conservation (Antoine Lavoisier, 1789)

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Antoine Lavoisier is known as the father of modern chemistry, and in 1789, he made a radical discovery: the law of mass conservation. He realized that in any chemical reaction, matter isn’t created or destroyed, it just changes form. 

For example, when you burn something, the total mass of what you start with is the same as what you end up with, even if it looks different. This discovery helped scientists understand that everything in the universe follows this basic rule!

17. Tesla’s Development of Alternating Current (Nikola Tesla, 1880s)

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In the 1880s, Nikola Tesla revolutionized how we use electricity by developing alternating current (AC). Before this, people used direct current (DC), which wasn’t very efficient over long distances. 

Tesla’s AC system, however, allowed electricity to travel much farther, making it more practical for powering homes and cities. Today, most of the world still uses Tesla’s AC system, making it one of the most important breakthroughs in modern technology.

18. Observation of Gravitational Waves (LIGO, 2015)

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Imagine hearing ripples in the fabric of space itself. In 2015, scientists at the LIGO observatory detected gravitational waves for the first time, proving a prediction made by Albert Einstein a century earlier. 

Gravitational waves happen when massive objects, like black holes, collide, sending waves through space. Detecting these waves was a major breakthrough because it gave us a new way to “listen” to the universe and understand events that are impossible to see with regular telescopes.

19. Foucault’s Pendulum and Earth’s Rotation (Léon Foucault, 1851)

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In 1851, Léon Foucault came up with a simple yet brilliant way to prove that the Earth rotates. He hung a huge pendulum from the ceiling and set it swinging.

Over time, the direction of the swing appeared to change, even though no one was touching it. 

This change was due to the Earth rotating beneath the pendulum. Foucault’s pendulum is still used today in science museums around the world to show that our planet is spinning.

20. Asteroid Deflection (NASA’s DART Mission, 2022)

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In 2022, NASA scientists pulled off an amazing feat—deflecting an asteroid! As part of the Double Asteroid Redirection Test (DART), they intentionally crashed a spacecraft into the asteroid Dimorphos to see if it could change the asteroid’s course. 

The spacecraft weighed 1,210 pounds and hit its target just 56 feet from the center, like a cosmic bull’s-eye. This mission showed that, in the future, we might be able to protect Earth from potential asteroid impact.

21. DNA Radiographs (Rosalind Franklin, 1952-1953)

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Rosalind Franklin’s work with DNA radiographs involved aspects of physics using a special method called X-ray crystallography, which took detailed pictures of tiny things to study DNA. These pictures, called radiographs, showed how the atoms inside DNA were arranged.

One of her most famous radiographs, called Photo 51, gave important clues about DNA’s shape. It helped scientists realize that DNA has a double helix structure, which looks like a twisted ladder. Without her radiographs, we might not have understood DNA as well or as quickly as we did.

22. Determining the Speed of Light (Armand Fizeau, 1849)

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Armand Fizeau, a French physicist, measured how fast light travels. He set up an experiment with mirrors and a spinning wheel to calculate the speed of light. 

His result was close to the modern value of about 186,282 miles per second. Knowing the speed of light is important for understanding everything from space travel to how we see the world around us.

23. Debunking the Luminiferous Ether (Albert Michelson & Edward Morley, 1887)

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For a long time, people thought that light needed something called “ether” to travel through space, much like sound needs air. In 1887, Albert Michelson and Edward Morley set up an experiment to detect this mysterious substance, known as the “luminiferous ether.” 

Their experiment didn’t find any evidence of it, which shocked scientists and eventually led to Einstein’s theory of relativity. They showed that light doesn’t need a medium to travel through—it can move through the vacuum of space.

24. The Discovery of Radioactivity (Henri Becquerel, 1896)

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Henri Becquerel was studying materials that glow under sunlight, and one day he left a piece of uranium on a photographic plate. To his surprise, the plate was exposed even without sunlight. 

This meant the uranium was giving off its own energy, a phenomenon later called radioactivity. Becquerel’s discovery led to further research by Marie and Pierre Curie, and it opened the door to nuclear physics and medicine.

25. The Universe’s Expansion (Edwin Hubble, 1929)

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In 1929, Edwin Hubble made an incredible discovery about the universe. By studying distant galaxies, he noticed that they were moving away from us. The farther a galaxy was, the faster it seemed to be retreating. 

Hubble’s discovery was a game-changer because it gave us the first clue that the universe had a beginning (which led to the idea of the Big Bang). 

26. The Leaning Tower of Pisa Experiment (Galileo Galilei, 1589)

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Galileo Galilei is said to have dropped two balls of different weights from the Leaning Tower of Pisa. People used to believe that heavier objects would fall faster than lighter ones, but Galileo proved them wrong. 

Both balls hit the ground at the same time, showing that all objects fall at the same rate, regardless of their weight (when there’s no air resistance). This experiment laid the foundation for our understanding of gravity and motion.

27. Nuclear Fusion Ignition (Lawrence Livermore National Laboratory, 2022)

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In 2022, scientists at the Lawrence Livermore National Laboratory in California successfully created a nuclear fusion reaction that produced more energy than it took to ignite it.

Nuclear fusion is the process that powers the sun, where atoms combine to release huge amounts of energy. This breakthrough could eventually lead to a clean and nearly unlimited source of energy, solving many of our current energy problems.

28. Calculating Earth’s Circumference (Eratosthenes, 240 B.C.)

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Way back in 240 B.C., Eratosthenes, a Greek mathematician, figured out how big the Earth is. He noticed that at noon on the summer solstice, the sun was directly overhead in one city, but cast a shadow in another city.

By measuring the angle of the shadow and the distance between the two cities, he calculated Earth’s circumference. His estimate was incredibly close to the actual size, showing just how clever early scientists could be!

29. Archimedes’ Eureka Moment (Archimedes, 3rd Century B.C.)

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Archimedes had his famous “Eureka!” moment in the 3rd century B.C. when he figured out how to determine the volume of an irregular object. While taking a bath, he noticed that the water level rose when he got in, and realized that the amount of water displaced could be used to measure the object’s volume. 

This discovery helped him solve a problem about whether a crown was made of pure gold without damaging it. His method became known as the principle of buoyancy.

30. Discovery of X-rays (Wilhelm Conrad Roentgen, 1895)

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In 1895, Wilhelm Conrad Roentgen noticed that a fluorescent screen in his lab started to glow, even though it wasn’t near the cathode ray tube. When he placed his hand in front of the tube, he could see the bones of his hand on the screen. 

X-rays revolutionized medicine, making it possible to see inside the human body without surgery, and Roentgen’s discovery earned him the very first Nobel Prize in Physics in 1901.

31. The Bell Test Experiment (John Bell, 1964)

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Physicist John Bell came up with a clever way to test a concept in quantum physics called entanglement. For instance, two particles that are connected in a way that changing one affects the other, no matter how far apart they are. 

Bell designed experiments, known as Bell Test experiments, to determine if particle connections were real or coincidental. His tests revealed that tiny particles behave in ways that challenge our understanding of reality.

This work has led to discussions about the nature of reality and the potential for quantum computing.

32. Quark Detection (CERN, 1968)

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In 1968, scientists at the CERN made a startling discovery about the building blocks of matter. They were studying protons and neutrons, which make up the nucleus of an atom. 

They found evidence of smaller particles called quarks inside protons and neutrons using a particle accelerator. This was important because quarks are considered fundamental components of matter, and understanding them helped physicists develop the Standard Model, which describes how particles interact in the universe.

33. OSIRIS-REx Asteroid Sampling Mission (NASA, 2023)

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Recently, NASA’s OSIRIS-REx spacecraft returned to Earth after a mission to collect samples from Bennu, a “potentially hazardous asteroid” with a 1-in-2,700 chance of colliding with Earth. The spacecraft brought back pieces of Bennu, helping scientists learn about the early solar system and the building blocks of life. 

By studying these samples, researchers aim to uncover secrets about planet formation and the materials in space, marking a major advancement in space exploration. 

These groundbreaking studies have opened doors to amazing possibilities in science and technology. As we continue to explore and experiment, who knows what new wonders we will uncover next?

Martha A. Lavallie
Martha A. Lavallie
Author & Editor | + posts

Martha is a journalist with close to a decade of experience in uncovering and reporting on the most compelling stories of our time. Passionate about staying ahead of the curve, she specializes in shedding light on trending topics and captivating global narratives. Her insightful articles have garnered acclaim, making her a trusted voice in today's dynamic media landscape.