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Watch: Richard Feynman makes scientific concepts beautifully simple

Few could match the famous physicist in his ability to communicate difficult-to-understand concepts in a simple and warm fashion.

  • Richard Feynman was a renowned physicist who conducted legendary work on quantum physics, the Manhattan Project, and investigating the Challenger explosion.
  • Later in life, however, he became best known for his education work, gaining the nickname "the Great Explainer."
  • His series, Fun to Imagine, works as an excellent primer to Feynman's unique educational style. Here are 9 science lessons he covers in his series.

Theoretical physicist Richard Feynman was unparalleled for his wit, warmth, and insightful understanding of theoretical physics. Being a gifted conversationalist with a powerful passion, Feynman loved to talk about theoretical physics and was good at it, so much so he was known as "the Great Explainer." Few others were able to approach the difficult and nebulous realm of physics and break it down into simple, entertaining, and informative nuggets of information. In his 1983 series Fun to Imagine, Feynman touches on a variety of topics from a big blue chair in his living room in Altadena, California. Here are 9 brief science lessons from this series.

1. Heat is just jiggling atoms

What we think of as heat is really just motion. Feynman explains that the sensation of heat is the "jiggling" of atoms — the jiggling atoms in hot coffee make it hot, and those atoms bump up against the atoms in the ceramic of your coffee mug, causing them to jiggle as well, making them hotter than they were before.

"It brings up another thing that's kind of curious," says Feynman. "If you're used to balls bouncing, you know they slow up and stop after a while. […] As it bounces, it's passing its extra energy, its extra motions, to little patches on the floor each time it bounces and loses a little each time, until it settles down, we say, as if all the motion has stopped." Instead, the downward motion of all the atoms in the ball have just been transferred into the floor, whose atoms are jiggling just a little bit more and has commensurately become just a little bit warmer.

Start the top video at 0:50 to watch this lesson.

2. Fire is stored sunlight

Carbon and oxygen have a somewhat paradoxical relationship; once "close" enough to one another, they form a very strong partnership, snapping together. But if they're too "far away" from one another, they'll repel each other. Feynman likens it to a hill with a deep hole in the top. "[An oxygen atom is] rolling along, it doesn't go down in the deep hole because if it starts to climb the hill, it rolls away again. But if you made it go fast enough, it'll fall into the hole."

As we learned before, when we talk about heat, we're really talking about motion, and vice versa. So, if we heat up an atom of oxygen enough, it can roll up this hypothetical hill and fall into the hole. On its way, it might bump into other atoms of oxygen, sending them rolling up their hills, and falling into their holes, which maybe bump other atoms of oxygen at the same time. This cascades, over and over again, until you have what we call a fire. Wood, for instance, contains a lot of carbon. If the oxygen around it heats up enough, the oxygen and the carbon can meet up and make a partnership together into the form of CO2, releasing a lot of energy along the way.

Where did this stored energy come from? Originally, it came from the sunlight striking a tree, which was then cut down and harvested for its wood. "The light and heat that's coming out," explains Feynman, "that's the light and the heat of the Sun that went in. So, it's sort of stored Sun that's coming out when you burn a log."

Start the top video at 7:18 to watch this lesson.

3. Rubber bands are jiggling, too

In addition to fire and the motion of atoms, heat is a big part of why rubber bands are stretchy. Rubber bands are composed of these kinked chains of molecules that, when stretched out, are bombarded by atoms from the environment that encourage those chains to kink up together again. Feynman proposes a little experiment: "If you take a fairly wide rubber band and put it between your lips and pull it out, you'll certainly notice its hotter. And if you then let it in, you'll notice its cooler."

"I've always found rubber bands fascinating," he adds. "The world is a dynamic mess of jiggling things if you look at it right."

Start the top video at 12:08 to watch this lesson.

4. Magnetic force? That's a challenge to explain!

Why do magnets repel? "You're not at all disturbed by the fact that when you put your hand on the chair, it pushes you back." With magnets, "we found out by looking at it that that's the same force as, a matter of fact […] It's the same electrical repulsions involved in keeping your finger away from the chair." The difference, Feynman notes, and the thing that makes magnets seem so unusual, is that their repulsive force acts over a distance. This is because the atoms in a magnet are all spinning in the same direction, magnifying the force such that you can feel it at a distance.

Start the top video at 14:53 to watch this lesson.

Richard Feynman while teaching.

Wikimedia Commons

5. Electricity: The reason you don't sink through the floor

It's pretty incredible that a wheel turning from the force of falling water from a dam can, when connected by copper wires, cause a motor to turn many miles away as well. If the wheel at the dam stops, so too does everything connected to that part of the power grid. "That phenomenon, I like to think about a lot. […] It's just iron and copper. If you took a big long loop of copper and add iron at each end and move the piece of iron, the iron moves at the other [end]."

In fact, electricity is the reason why you can't push your finger through a solid object. The negatively charged electrons in your finger are tightly bound to the positively charged protons in your finger, and the same relationship holds true for any solid object. Once you try to push your finger through something, the respective protons and electrons can't tolerate the addition of any more positive or negative charge — the electrical charge in your finger's atoms are neutral, and want to stay that way. So, the object and your finger push back very hard on one another.

In a wire conducting electricity, the electrical charge of the atoms is not neutral. The energy derived from, say, a dam, pushes electrons from one atom out, which repels the other electrons along the wire. We can use this energy to move a motor on the far end of the wire or turn on a light.

Start the top video at 22:29 to watch this lesson.

6. The mirror and train puzzle

Feynman described two puzzles he was given by his fraternity brothers at MIT. Why is it that when you look at yourself in the mirror, only the left and right sides are reversed and not the top and bottom of the reflected image? How does the mirror know to flip an image along one axis and not the other? Well, if you were facing a mirror with your nose facing north, the left and right sides aren't actually flipped—your right hand and your reflected image's right hand are both in the east. It's your front and back that have been flipped: Your nose faces north, and your reflected image's nose faces south.

Feynman thought this was an easy puzzle. A harder one is to ask what keeps a train on a track. When turning a corner in a car, the outside wheels have to go farther than the inside wheels, but cars deal with this using a differential gear, which helps each wheel to turn at different rates. Trains, though, have a solid steel bar between each of their wheels. How does the train stay on the track? The answer is that trains have conical wheels. When a train turns a corner, the inside wheels are riding on the thinner part, meaning they can rotate quickly without going too far, while the outside wheels are riding on the thicker part of the cone, meaning they have farther to go to make one rotation.

Start the top video at 32.05 to watch this lesson.

7. Your eyes are eighth-inch black holes

If a sufficiently intelligent bug were sitting in the corner of a pool, they could, in theory, observe the waves in the pool and determine who had dived in. This is what we do with our eyeballs. Like the bug in a pool, we simply take in this shaking stuff (the electromagnetic field) and can learn which objects have "dived" into our pool.

"There's this tremendous mess of waves all over in space, which is the light bouncing around the room and going from one thing to the other. Of course, most of the room doesn't have eighth-inch black holes [our pupils]. It's not interested in light, but the light's there anyway." We can sort this mess out with the instruments we carry around in our eye sockets. Feynman explains that our eighth-inch black holes are only tuned to a small slice of the waves in this pool. But the other waves, bigger ones or smaller ones, we experience as heat or as sound broadcasted from radios. The craziest thing about this to Feynman? "It's all really there! That's what gets you!"

Start the top video at 37:46 to watch this lesson.

8. Conceiving of inconceivable things

Scale, whether looking at very small things or very big things, is very difficult to conceptualize. The size of an atom compared to an apple, for instance, is the same as the size of an apple to the size of Earth. Feynman explains how difficult it is to consider very large scales, as well: "There's a very large number of stars in the galaxy. There's so many, that if you tried to name them, one a second, naming all the stars in our galaxy, […] it takes 3,000 years. And yet that's not a very big number. If those stars were to drop a one-dollar bill during a year, […] they might take care of the deficit which is suggested for the budget of the United States. You can see what kind of numbers we're dealing with."

Start the top video at 43:43 to watch this lesson.

9. Thinking is kind of nutty

Sometimes, we like to mythologize particularly impressive people, Feynman included. But thinking this way can be limiting. Feynman doesn't believe there are particularly "special" people — just those who work and study hard. That's not to say there's no difference between people, however. "I suspect that what goes on in every man's head might be very, very different. The actual imagery, or semi-imagery which comes when we're talking to each other at these high and complicated levels […] We think we're speaking very well and we're communicating, but what we're doing is having this big translation scheme for translating what this fellow says into our images, which are very different."

Start the top video at 55:01 to watch this lesson.

Neom, Saudi Arabia's $500 billion megacity, reaches its next phase

Construction of the $500 billion dollar tech city-state of the future is moving ahead.

Credit: Neom
Technology & Innovation
  • The futuristic megacity Neom is being built in Saudi Arabia.
  • The city will be fully automated, leading in health, education and quality of life.
  • It will feature an artificial moon, cloud seeding, robotic gladiators and flying taxis.
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Human brains remember certain words more easily than others

A study of the manner in which memory works turns up a surprising thing.

Image Point Fr / Shutterstock
Mind & Brain
  • Researchers have found that some basic words appear to be more memorable than others.
  • Some faces are also easier to commit to memory.
  • Scientists suggest that these words serve as semantic bridges when the brain is searching for a memory.

Cognitive psychologist Weizhen Xie (Zane) of the NIH's National Institute of Neurological Disorders and Stroke (NINDS) works with people who have intractable epilepsy, a form of the disorder that can't be controlled with medications. During research into the brain activity of patients, he and his colleagues discovered something odd about human memory: It appears that certain basic words are consistently more memorable than other basic words.

The research is published in Nature Human Behaviour.

An odd find

Image source: Tsekhmister/Shutterstock

Xie's team was re-analyzing memory tests of 30 epilepsy patients undertaken by Kareem Zaghloul of NINDS.

"Our goal is to find and eliminate the source of these harmful and debilitating seizures," Zaghloul said. "The monitoring period also provides a rare opportunity to record the neural activity that controls other parts of our lives. With the help of these patient volunteers we have been able to uncover some of the blueprints behind our memories."

Specifically, the participants were shown word pairs, such as "hand" and "apple." To better understand how the brain might remember such pairings, after a brief interval, participants were supplied one of the two words and asked to recall the other. Of the 300 words used in the tests, five of them proved to be five times more likely to be recalled: pig, tank, doll, pond, and door.

The scientists were perplexed that these words were so much more memorable than words like "cat," "street," "stair," "couch," and "cloud."

Intrigued, the researchers looked at a second data source from a word test taken by 2,623 healthy individuals via Amazon's Mechanical Turk and found essentially the same thing.

"We saw that some things — in this case, words — may be inherently easier for our brains to recall than others," Zaghloul said. That the Mechanical Turk results were so similar may "provide the strongest evidence to date that what we discovered about how the brain controls memory in this set of patients may also be true for people outside of the study."

Why understanding memory matters

person holding missing piece from human head puzzle

Image source: Orawan Pattarawimonchai/Shutterstock

"Our memories play a fundamental role in who we are and how our brains work," Xie said. "However, one of the biggest challenges of studying memory is that people often remember the same things in different ways, making it difficult for researchers to compare people's performances on memory tests." He added that the search for some kind of unified theory of memory has been going on for over a century.

If a comprehensive understanding of the way memory works can be developed, the researchers say that "we can predict what people should remember in advance and understand how our brains do this, then we might be able to develop better ways to evaluate someone's overall brain health."

Party chat

Image source: joob_in/Shutterstock

Xie's interest in this was piqued during a conversation with Wilma Bainbridge of University of Chicago at a Christmas party a couple of years ago. Bainbridge was, at the time, wrapping up a study of 1,000 volunteers that suggested certain faces are universally more memorable than others.

Bainbridge recalls, "Our exciting finding is that there are some images of people or places that are inherently memorable for all people, even though we have each seen different things in our lives. And if image memorability is so powerful, this means we can know in advance what people are likely to remember or forget."

spinning 3D model of a brain

Temporal lobes

Image source: Anatomography/Wikimedia

At first, the scientists suspected that the memorable words and faces were simply recalled more frequently and were thus easier to recall. They envisioned them as being akin to "highly trafficked spots connected to smaller spots representing the less memorable words." They developed a modeling program based on word frequencies found in books, new articles, and Wikipedia pages. Unfortunately, the model was unable to predict or duplicate the results they saw in their clinical experiments.

Eventually, the researchers came to suspect that the memorability of certain words was linked to the frequency with which the brain used them as semantic links between other memories, making them often-visited hubs in individuals's memory networks, and therefore places the brain jumped to early and often when retrieving memories. This idea was supported by observed activity in participants' anterior temporal lobe, a language center.

In epilepsy patients, these words were so frequently recalled that subjects often shouted them out even when they were incorrect responses to word-pair inquiries.

Seek, find

Modern search engines no longer simply look for raw words when resolving an inquiry: They also look for semantic — contextual and meaning — connections so that the results they present may better anticipate what it is you're looking for. Xie suggests something similar may be happening in the brain: "You know when you type words into a search engine, and it shows you a list of highly relevant guesses? It feels like the search engine is reading your mind. Well, our results suggest that the brains of the subjects in this study did something similar when they tried to recall a paired word, and we think that this may happen when we remember many of our past experiences."

He also notes that it may one day be possible to leverage individuals' apparently wired-in knowledge of their language as a fixed point against which to assess the health of their memory and brain.

Does conscious AI deserve rights?

If machines develop consciousness, or if we manage to give it to them, the human-robot dynamic will forever be different.

  • Does AI—and, more specifically, conscious AI—deserve moral rights? In this thought exploration, evolutionary biologist Richard Dawkins, ethics and tech professor Joanna Bryson, philosopher and cognitive scientist Susan Schneider, physicist Max Tegmark, philosopher Peter Singer, and bioethicist Glenn Cohen all weigh in on the question of AI rights.
  • Given the grave tragedy of slavery throughout human history, philosophers and technologists must answer this question ahead of technological development to avoid humanity creating a slave class of conscious beings.
  • One potential safeguard against that? Regulation. Once we define the context in which AI requires rights, the simplest solution may be to not build that thing.

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