10 Examples of Physics From Everyday Life

law of inertia of motion

Not every student will grow up and study physics on a deeper level, but physics extends well into our daily life, describing the motion, forces and energy of ordinary experience. Therefore, it should be possible to illustrate to anyone the physics of everyday life, with examples of course.


Image formation

Have you noticed that when standing inside a room at night, you can often see your reflection in a pane of glass? In similar way, because there is much less light coming from the bottom of a lake, the surface of the lake will act like a mirror.

reflection of light

But an image can also be formed by refraction. A fish seen in the water will usually appear to be at a different depth than it actually is, due to the refraction of light rays as they travel from the water into the air.

refraction of light virtual image

Lastly, there exist phenomena which appear due to combination of reflection and refraction. For example, a rainbow is seen when light passes through water droplets hanging in the atmosphere. The light bends, or refracts, as it enters the droplet, and then reflects off the inside of the raindrop.

how rainbow forms after rain


Washing machine

The dryer of washing machine is a rapidly rotating container that applies centrifugal force to its contents. The centrifugal force acts in a direction away from the centre and hence can be used to throw the water molecules on the clothes radially outwards during the spin cycle of the washing machine.


Static electricity

When two objects that are not good electrical conductors are rubbed together, electrons from one of the objects rub off onto the other.

static electricity funny images animated

The more rubbing between two objects, the more static electricity build up and the larger the electrical charge.


Road safety

When brakes are applied to a moving car, the car and lower portions of the passengers attached to the car come to immediate stop, but their upper portions fall forwards, because of inertia. This is why seat belts as well as air bags are installed in the car.

inertia safety belts in car


Roller coaster

The first hill of the ride is always the highest one so that the car collects enough energy to go through all the elevations. As the car goes down, its potential energy decreases but kinetic energy increases. If added together at any part of the ride, the kinetic and potential energies of the car will equal the potential energy that the car had on the first hill.


Spinning

When the figure skater draws her arms and a leg inward, she reduces her moment of inertia thus rotating at a faster angular speed. This is due to conservation of angular momentum.

angular momentum figure skating


Handle of the door

If you apply force close to the hinge of the door, the door will not open as it will not be able to rotate about the hinge. But, when you apply the same force farther away from the hinge, the torque will be larger. Hence, the door opens easily with less effort.


Falling down

Suppose you are climbing a tree, and suddenly you slip and fall down from the tree. Then, you may break a bone or two. But if same thing happens to a little ant, that is, if it falls down from height, it does not get hurt. Why is it so?

From ant’s point of view, the atmosphere is thick and viscous and its experience of falling from a height is similar to ours when we fall through water to the bottom of the pool. The air underneath the falling ant becomes like a large cushion of safety.


Roundness

Nobel prize winning physicist Richard Feynman explains why little drops of water are round in the following video.



Sound game

When a water bottle fills up, the air column or amount of air inside the bottle decreases. As a result, the pitch (or shrillness) of the sound will increase, as it is inversely proportional to the length of vibrating air column. Therefore, you can tell exactly when the bottle is full without even looking.



Summing up

It is hard to imagine of life without physics. Even though one may not be equipped with the kind of mathematics required to fully understand these physical phenomena, one can surely appreciate the fact that they are there. Lots of other examples are available and you just need the eye to recognize them.

Dirac, a fusion of genius and madness, according to Einstein

Paul Dirac Famous Anecdotes

Paul Dirac, one of the most famous scientists of the 20th century, was a very quiet man. So much so, that his colleagues at Cambridge jokingly defined a unit of speech called "dirac", which meant one word per hour!

But whenever he did speak, Dirac used to extend his abstract thinking to interpret the world literally. This inevitably led him to being an anecdote generator throughout his life and many stories about him abound.

Why do you dance?

In 1929, Dirac and Heisenberg were on board a ship to Japan for attending annual science conference. Werner Heisenberg who happened to be quite a ladies man, used to dance with the young girls on the ship before dinners, while Dirac used to sit watching.


One such evening, Dirac asked, "Heisenberg, why do you dance?"

"When there are nice girls, dancing with them is a pleasure," Heisenberg replied.

Dirac pondered this notion for a while, then blurted out: "But, how do you know beforehand that the girls are nice?"

Heisenberg burst out with laughter.


Physics versus poetry

Dirac and Oppenheimer spent some time together in Göttingen. The two young physicists from different parts of the world had become good friends. In one of these days, Dirac noticed that Oppenheimer wrote poetry.

Dirac asserted, "Robert, I do not understand how a man can work on the frontiers of physics and write poetry at the same time."

Paul Dirac, Robert Oppenheimer Poetry Anecdote

"Why not?" Oppenheimer asked.

"In physics, you want to tell something that nobody knew before, in words which everyone can understand. In poetry, however, you go on to describe something that everybody knows about, in incomprehensible ways."

Oppenheimer was left too confused to respond to that.

Dirac went on to say, "The two are incompatible!"

His comments would strike people as odd at first but they would quickly realize that Dirac made perfect logical sense.


Finish this sentence

Once, Dirac and Bohr were seated in the same room. Niels Bohr, known for being a perfectionist, was writing a scientific paper while mumbling at the same time as was his habit.


After some time, Bohr became really frustrated and stopped. He complained, “I do not know how to finish this damn sentence!”

Dirac retorted, "I was taught at school, never to start a sentence without knowing the end of it."

Dirac said something so profound, with such a straight face, that Bohr went on to comment, "Dirac was the strangest man who ever visited my institute!"


I have an equation

American physicist, Richard Feynman, born in 1918, grew up idolizing Dirac. About 40 years later, they met in Poland at a conference. Richard Feynman, by then a theoretical physicist himself, was building upon Dirac's great work.

Paul Dirac and Richard Feynman in Poland discussing QED

Feynman, the chatty one, spoke at length, as he wanted to describe new ideas to his hero. Dirac, perhaps intimidated by Feynman's over-enthusiasm, remained quiet all along.

Feynman started to see that it was extremely difficult to get anything out of Dirac. But then, after a long silence, Dirac says, "I have an equation. Do you have one too?"

Dirac also went on to explain as to why he spoke so little, “There are always more people willing to speak than there are to listen.”


That wasn't a question

In 1932, Dirac was appointed the Lucasian Professor of Mathematics at the University of Cambridge. During one lecture in class, a student raised his hand and said, "I don't understand the equation on the top-right-hand corner of the blackboard."

Dirac simply nodded his head in agreement and continued unabated. When asked again, he expressed puzzlement because he thought the student had simply uttered a fact and not asked a question.


Summing up

Paul Dirac knew not when to say what. He remained merry in his own company but suffered agonies if forced into any kind of socializing or small talk.

His colleagues  in Cambridge described him as a “lean, meek, shy young fellow who goes slyly along the streets, walks quite close to the walls, like a thief, and is not at all healthy.”


Albert Einstein once commented on Dirac: "I have a lot of trouble with Dirac. This balancing on the dizzying path between genius and madness is awful!"

Dirac quantised the gravitational field, formulated the most logically perfect presentation of quantum mechanics and predicted the existence of anti-matter. At the same time, he was also equally famous for his strange, unapologetic behavior.

Nikola Tesla, a college dropout who changed the world

nikola tesla biography

On 10th of July in 1856, Nikola Tesla was born at midnight during a lightning storm. The midwife thought the violent storm was bad omen, "This will be a child of darkness", she declared mindlessly."No, replied Tesla's mother, "he will be a child of light".

His father, Milutin Tesla, was orthodox christian priest while his mother, Đuka, was hard working housewife. They recognized very early that their son was unlike other children. Young Tesla was creative, curious and blessed with photographic memory.


Milutin, a devout man, wanted his son to become priest like himself but Đuka encouraged Nikola to study science instead. Even though she had never received formal education, Đuka had the talent for making mechanical appliances at home.

nikola tesla biography
Nikola Tesla's parents

By the age of 16, Nikola was able to perform integral calculus in his head which prompted his teachers to believe that he was cheating. Tesla credited his eidetic memory and creative abilities to his mother's genetics and influence.

He finished four-year high school term in three years graduating in 1873. During those times, high school graduates were forced to join the military but Tesla ran away and remained hidden for over a year wearing hunter's garb to escape conscription.

Tesla returned in 1875. Then, he enrolled for engineering degree at Graz University of Technology in Austria.

In first year, he never missed a lecture, earned the highest grades and even received letter of commendation from the dean to his father, which stated, "Your son is a star of first rank."

nikola tesla biography

But 20-year old Nikola was mortified when his father made light of those hard won honors. In second year, Tesla came into conflict with his professor when he suggested that commutators would be unnecessary in the Gramme Dynamo.

Tesla lost the scholarship money as he became addicted to gambling. In third year, he did not even sit for the examination. He severed all relations with family to hide the fact that he had dropped out. At age 22, without contacting anyone, Nikola moved to Slovenia in search of work.

His family thought that he had committed suicide but one year later,

In March of 1879, Milutin learned that his son was seen in Maribor, the second-largest city of Slovenia. He went to Maribor to beg his son to return home. Tesla refused.

nikola tesla biography
street where Tesla lived in Maribor

Milutin was despaired. In April of 1879, he passed away aged 60. After hearing the news, Nikola returned home but too late though.

A sorrowful Nikola recalled, "My father wanted me to enter priesthood but in one of the sinking spells due to Cholera, which was thought to be the last, he rushed into my room. I still see his pallid face as he tried to cheer me up..

"Perhaps," I said, "I may get well if you will let me study engineering."

"You will go to the best technical institution in the world," he solemnly replied.

Nikola was lost and depressed especially after death of his father. He stayed home for few months. Then, he started teaching at his old primary school. He taught there until January 1880.


Next, he went to Prague and attended lectures in philosophy for a year. In 1881, Nikola moved again, this time to Budapest to work for Budapest Telephone Exchange. He was 25 years old.

nikola tesla biography

In 1882, he was employed as electrician by Continental Edison Company in Paris to install incandescent lighting. The management took notice of his advanced knowledge and soon he was promoted.

"In 1884, I was brought in intimate contact with Edison. His mind was dominated by one idea, to leave no stone unturned and to exhaust every possibility. We experimented for days and nights, holidays not excepted."

During this time, Edison made an outstanding offer. In exchange for redesigning generators, Tesla was promised a hefty cash prize.

But he was taken advantage of as it turned out to be a practical joke. Therefore, in January 1885, a furious Tesla left note for Edison which read, "Goodbye to the Edison Machine Works."

For a brief while, Nikola Tesla remained jobless in America.

nikola tesla biography

Then, with help from interested investors, Tesla founded a company in his own name, Tesla Electric Light & Manufacturing (1885). He worked for the rest of the year acquiring patents for improved design of DC generator which had gained recognition in the press.


But Nikola was not business-ready yet.

In 1886, the investors obtained control of the patents, renamed the company to Union County Electric Light & Manufacturing and left Tesla penniless in the process.

"My life seemed to me like mockery."

Yet, Tesla did not give up as he set about to create another company, this time with more caution, in 1887. He invented commutator-less induction motor in the same year. This innovative machine which ran on alternating current was patented by Tesla in May of 1888.

Soon, $15,000-a-year royalty deal was made for the new type of motor with Westinghouse Electric Company.

nikola tesla biography
Induction motor by Tesla

But two years after signing the Tesla contract, George Westinghouse was in deep financial trouble. Also, at this time, Edison came out with all guns blazing against the alternating current movement, saying, "It is too dangerous. Direct current is safe."



In 1891, Westinghouse explained his situation to Nikola Tesla and Tesla agreed to release Westinghouse Company from the royalty payment.

Six years later, when all troubles sorted, direct current defeated, Westinghouse purchased Tesla's 1888 motor patent for a lump-sum of $216,000. The money made Tesla independently wealthy and gave him the time and funds to pursue his own interests.

Nikola Tesla went on to obtain around 300 patents in over 25 countries for his inventions. Tesla coil, remote control, induction motor, neon lamp, wireless telegraphy to name a few.

nikola tesla biography
on the cover (1931)

Tesla died on 7 January in 1943 at the age of 86. He never married, did not have any children and devoted his life totally to the pursuit of knowledge and innovation.

"To me[Nikola Tesla], the universe is simply a great machine which never came into being and never will end and what we call 'soul' or 'spirit,' is nothing more than the sum of the functionings of the body. When this functioning ceases, the 'soul' or the 'spirit' ceases likewise".

Characteristics of Physical Law


Despite numerous limitations, we human beings are able enough to study as well as appreciate the grandeur of the universe. Our great journey of determining scientific laws began as we understood the regular repetitions of the day and night, the annual cycle of seasons, the eclipses, the tides, the volcanoes, the rainbow and so on.


What is scientific law?

A scientific law is verbal or mathematical explanation that describes some phenomenon of the natural world. For example, Newton's law of gravity, which states that every particle attracts every other particle in the universe with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers. But the law itself does not explain why the phenomenon exists or what causes it: that is really the job of theory, in this case, Einstein's theory of general relativity.

The scientific law is factual and should not be confused with logical truth. For example, "boiling point of water is 100 degrees celsius" is a law whereas "every number has a double" is logical truth and not really a law.


Constant over space and time

The same laws which apply here on earth also apply to the rest of the universe. For example, Galileo's law of falling bodies was tested on the moon by astronaut David Scott in 1971.


This is simple and yet beautiful truth, that the laws of nature are universally valid. There are no laws of nature that hold just for the planet earth or the Andromeda Galaxy, for that matter.

In addition, the laws of nature do not change as time progresses. There is a joke which goes something like this, "Before Newton discovered gravity, all things could fly." That is so not the case; there are no laws of nature that hold just for the eighteenth century or just for the Mesozoic Era.



Same for animate and inanimate

The laws are same for living beings and for inanimate objects. There is no evidence yet that what goes on in living creatures is necessarily different, so far as the physical laws are concerned, from what goes on in non-living things.

For example, conservation of angular momentum is a fundamental law of nature. A rotating ballerina spins faster when drawing her arms in.

how are physical laws symmetrical?

Similarly, the earth and other planets revolving around the sun obey the law of conservation of angular momentum, which is why, when a planet is nearer to the Sun, the orbital speed increases and when it is farther away, it slows down.


Simple in nature

Eminent kiwi physicist Ernest Rutherford used to say, "it should be possible to explain the laws of physics to a barmaid." But even though the laws themselves are so simple, their implications are far and wide.

For example, Newton's third law of motion is simply, "for every action there is equal and opposite reaction", and yet it is noticeable in many instances of life such as in walking, swimming, recoiling of gun, and most importantly, rocket propulsion.

how are physical laws symmetrical?

Similarly, Newton's second law of motion is just, F=ma, but it made possible the industrial revolution. Steam engines, locomotives, factories, machines, all of it due to the mechanics set into motion by the second law of motion.


Same in uniform motion

If we have an experiment working in a certain way and then take the same apparatus, put it in a car, and move the whole car, plus all the relevant surroundings, at a uniform velocity in a straight line, then so far as the phenomena inside the car are concerned, there is no difference.


Unification of laws

Scottish physicist James Clerk Maxwell took a set of known experimental laws such as Faraday's Law, Ampere's Law and unified them into a symmetric coherent set of equations known as Maxwell's equations.

how are physical laws symmetrical?

Maxwell's equations are also laws just like the law of gravity. They govern the behavior of electric and magnetic fields. Also, light itself is an electromagnetic wave. Therefore, Maxwell's equations have in a way unified three separate phenomena, electricity, magnetism and optics, into one.

A similar type of unification occurred in the early part of the 20th century. The laws of conservation of energy and conservation of total mass were proven to be equivalent by German physicist Albert Einstein in a simple equation, E=mc^2.


These unifications are possible because the laws of physics are symmetrical in nature. Two or more distinctly appearing natural phenomena appear to be governed by just one simple law. Thus, one day, we may be able to find an ultimate law of physics that may explain everything.

Renowned American physicist Richard Feynman had famously said, "God is always invented to explain those things that you do not understand."

Throughout history, man has credited god for this or that phenomena. For example, early Greeks believed that lightning was a weapon of Zeus. Now, when you finally discover how something works, you get some laws which you're taking away from god; you don't need god anymore.

Thus, "what one man calls god, another calls the laws of physics," or in other words, to have an understanding of the physical laws is in a way a liberation from all superstition.

How To Study Physics By Using Feynman Technique

how to learn by feynman technique

Richard Feynman was one of the world’s greatest scientists who won a nobel prize for physics in 1965. But we recognize him more as an outstanding teacher, a story-teller and an everyday joker whose life, was a combination of his intelligence, curiosity and uncertainty.

Feynman was once asked in an interview whether an ordinary person could understand physics like him. After a brief pause, "of course!", he replied candidly. "I was an ordinary person who studied hard."

In this post, you will learn to study physics by using the Feynman Technique, a method involving four easy steps, which was designed to help you understand concepts you don't get and to remember stuff you've already learned.

1. Write

how to learn by feynman technique

This is a no-brainer. Always write down everything you know about the topic on a notebook page. Add examples and illustrations in your notes whenever possible.

Why is it important to write? Because writing anything down makes us remember it better. This is also the reason why many life coaches advise to pen down our goals.


2. Explain

Describe whatever you have learned to an empty room. This step will not only test memorization but also help you to become a better teacher.

how to learn by feynman technique

Yes, many of you may not want to go into the teaching profession but it is a good practice to convey your learning in loud words. Remember, teaching is a powerful tool to learning.


3. Analyze

There is a famous saying which many attribute to Feynman, "If you cannot explain it simply, you do not understand it", which is fairly obvious.

how to learn by feynman technique

Did you teach it well? Where is the gap in your understanding? Identify it. Then, revisit your notes for revision.

Revision often increases your confidence because the gap in your understanding is reduced. You may even want to rewrite your notes in a more simple language than before.


4. Repeat

Because of revision, you should have a better grasp of the subject. So gather one of your friends and explain the topic once again, to him/her. This step is powerful because when one teaches, two learn.

how to learn by feynman technique

At the end, take feedback from your friend as that might help in understanding any remaining gaps. Did you know that Professor Walter Lewin, famous for his physics videos on YouTube, used to teach at least five times to an empty hall, before actually taking the class?


Summing up

Feynman had once said, "I don't know what's the matter with people: they don't learn by understanding; they learn by some other way, by rote or something. Their knowledge is so fragile!"

But if you follow what is known as the Feynman Technique, as described here, you will be able to learn more efficiently and firmly. It is a tried and tested method so please share this post with fellow students.

Who was Carl Sagan?

Carl Sagan Biography For Teenagers

As a scientist, Carl Sagan contributed enormously to our knowledge of the solar system. He correctly predicted the existence of methane lakes on Saturn's largest moon Titan. When other astronomers had imagined Venus to be a balmy paradise he showed it to be dry, thick and unpleasantly hot. Carl went on to propose that the atmosphere of the early earth must have contained powerful greenhouse gases.


When she returned, all of Carl's enthusiasm turned into utter disappointment. She had with her a book on the Hollywood stars, wait what, those weren't the kind of stars that concerned an astronomer.

The librarian, a little embarrassed, shifted her attention to a different bookshelf. After searching for a while, she brought with her the correct book, titled, "secrets of the stars". She handed it to the young astronomer. This incident made a deep and lasting impression on a young Carl Sagan.


Career at NASA

Carl Sagan attended the University of Chicago where he came under the guidance of famous physicists such as Enrico Fermi and Edward Teller. As an undergraduate he worked for geneticist H.J. Muller and wrote a thesis on the origins of life.

Carl Sagan Biography For Teenagers

Carl Sagan went on to earn a masters in physics in 1956, before earning a PhD degree in 1960.

Then he became a visiting scientist to NASA's Jet Propulsion Laboratory where he contributed to the making of the first Mariner orbiter mission to Venus.

The Mariner Orbiter confirmed his conclusions on the surface conditions on Venus in 1962. He also worked closely with NASA for the successful landing of man on the moon in 1969.


Next, he worked with NASA for the Viking space program which  was set up to explore the habitat and environment of planet Mars. For the first time in human history, a man-made object had landed on an alien world.

Carl Sagan Biography For Teenagers
viking on mars, 1976

However, the viking landing did not receive attention it deserved. The general public was widely unaware of a significant success in the field of space exploration. Was it not important to people? Was it not worth their time? These questions began to haunt Carl's imagination.

Therefore, just two years later in 1978, Carl Sagan began to work for a new TV show, Cosmos: a personal voyage. Its objective was to narrate to people the story of cosmic evolution, sciences and civilization. In 1980, the first episode of Cosmos was aired and became an instant hit.


Cosmos

Using the word "cosmos" rather than the word universe implies viewing the universe as a complex and orderly system; the opposite of chaos. Nobody had ever explained space, in all its bewildering glory, as well as Sagan did.

Carl Sagan Biography For Teenagers
ship of the imagination

Cosmos was seen in over 60 countries by more than 500 million people. It was the biggest show of the eighties.

In the fifth episode of the series, Sagan explained the kind of experiments performed by viking on the surface of planet Mars. The episode ends with the possibility of the colonization of Mars which became inspiration for the likes of Elon Musk.


During the same time, he was also working with NASA for the voyager space program whose mission was to investigate the outskirts of the solar system for signs of life.

Voyager 1, which had completed its primary mission and was leaving the Solar System, was commanded by NASA to turn its camera around and take one last photograph of Earth across a great expanse of space, at the request of Carl Sagan.

This picture is called The Pale Blue Dot.

Carl Sagan Biography For Teenagers
consider again that dot

Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light.

The earth is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.


People's Astronomer

Through his appearances on TV and eloquent writings, he has shown many a times how space humbles as well as lifts. He brought astronomy into our living rooms.

Today, the word "cosmos" is on everyone's lips thanks to Carl Sagan. He made astronomy more accessible to people by popularizing it.

Carl Sagan Biography For Teenagers

In fact, Carl Sagan turned astronomy into a deep spiritual experience.

That we are not different from space but a little part of it, made from it. The nitrogen in our DNA, calcium in our teeth and iron in our blood were first forged in the interiors of the dying stars. That we are the star-stuff contemplating the stars is well and truly a great spiritual realization.

Top 10 Experiments in Physics History

all time top 10 experiments conducted in physics
Great physics experiments (image of science museum London)

Physics is an exploratory science. New experiments in physics change or expand our existing knowledge in one way or another. Let us find out how this has happened in history.


10. Galileo's Tower of Pisa experiment

Before Galileo, a majority of people used to follow the teachings of ancient Greek philosopher, Aristotle, who had proclaimed that different weights when dropped from same height experienced different amounts of attraction from the Earth thus falling at different speeds.

It is said that in 1589 Galileo climbed atop Tower of Pisa and dropped two objects of different masses in order to debunk Aristotelian belief.

all time top 10 experiments conducted in physics

In 1971, astronaut David Scott re-created Galileo's famous experiment on the moon by dropping a hammer and a feather simultaneously. You can watch it happen in this clip.



9. Faraday's law of induction

A sudden movement of a magnet through a coil produces a reading on the galvanometer meaning that a changing magnetic field can induce an electric current in the coil.

top 10 experiments conducted in physics

This observation was first made by Michael Faraday in the year 1831. Today, electric generators use the same principle to convert mechanical energy into electrical energy that powers our household electric appliances.


8. Michelson Morley experiment

Does light, like other waves, require a medium to travel? Scientists of the 19th century thought so. They proposed the existence of an invisible stationary substance permeating through all of space that they named aether.

top 10 experiments conducted in physics

In the 1880s, American physicist Albert Michelson thought of discovering the aether.

If aether really exists, Earth moving through it would cause a wind in the same way that there seems to be a wind outside a moving car.


To a person in the car, the air outside the car would seem like a moving substance. In the same way, aether should seem like a moving substance to things on Earth.

Michelson designed an interferometer to measure the speed of the "aether wind" in 1887 along with one of his colleagues, Edward Morley.

top 10 experiments conducted in physics

However, no aether wind was detected by the experimental setup making it the most famous failed experiment in history. But, it had been shown that light required no substance medium whatsoever to travel in space.


7. Double slit experiment

Newton believed that light was a stream of energy-carrying particles. But he was proven wrong by Thomas Young, in 1801, who demonstrated with experiment that light was a wave.

top 10 experiments conducted in physics

In this experiment, when light emitted from two sources is forced to interfere, an unexpected pattern is formed on a distant screen. This interference pattern can be explained by wave theory of light only.


6. Discovery of electron

The atom was greatly regarded as the smallest possible structure in the universe. In 1897, however, Joseph Thomson performed a groundbreaking experiment suggesting that atom was divisible.

top 10 experiments conducted in physics

Thomson used a cathode ray tube, which is a vacuum-sealed glass tube with a cathode and anode fixed inside it. A beam of electrons was observed to move from one end to another upon the application of high voltage.

Thomson also identified that electron was not electrically neutral because he observed a deflection in the beam when an external electric field was applied.


5. Photoelectric effect

top 10 experiments conducted in physics

In 1887, German experimental physicist Heinrich Hertz stumbled upon an amazing phenomenon, the photoelectric effect. He discovered that certain metal electrodes when illuminated by the UV light produced electric sparks.

Two decades later, Einstein proposed an explanation of the photoelectric effect using a concept first put forward by Max Planck that light waves consist of tiny bundles or packets of energy known as photons or quanta.


4. Davisson Germer experiment

top 10 experiments conducted in physics

It was proposed by physicist Louis de Broglie that matter had particle as well as wave nature simultaneously. Davisson and Germer set about to test de Broglie's hypothesis in laboratory.

If electron could behave like a wave, it could interfere with another electron wave much like the light waves do. In 1925, the duo succeeded in obtaining interference pattern.

top 10 experiments conducted in physics


3. Gravity probe b

This was a satellite-based experiment which was launched on 20 April, 2004 by NASA. Its mission was to measure the space-time curvature around the earth as proposed by Einstein. Total cost of this project was about $750 million.

top 10 experiments conducted in physics

This was accomplished by measuring the tiny changes in the direction of spin of four gyroscopes contained in the satellite. Initial results confirmed the expected geodetic effect to an accuracy of about 1%.

2. Higgs boson discovery

The Higgs field is a field of energy that is thought to exist in every region of the universe. The field is accompanied by a fundamental particle known as the Higgs boson, which is used by the field to continuously interact with other particles, such as the electron.

top 10 experiments conducted in physics
Higgs interaction

In 2012, the particle was finally discovered. Peter Higgs became a worldwide sensation and a Nobel Prize winner.


1. LIGO experiment

The Laser Interferometer Gravitational-Wave Observatory is a large-scale physics observatory which was designed to detect cosmic gravitational waves as predicted by Einstein's general theory of relativity.

top 10 experiments conducted in physics

By 2017, LIGO had made five detections of gravitational waves, the first four of which were because of colliding black hole pairs. The fifth event, on August 17, 2017, was the first detection of a collision of two neutron stars.

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