Yo-yo, one of the world's oldest toys!

Yo-yos might be one of the oldest toys in the world, but a U.S. patent was awarded for it on November 20, 1866, based on a design improvement. Still popular around the globe, yo-yos have been with humankind for thousands of years.

When you played with a yo-yo, have you ever wondered when and where this toy came from? The truth is, we don't have an exact answer for either…. While historians suggest that the toy likely originated from what is now Greece, China, or the Philippines, yo-yos have been around for thousands of years. In fact, archaeological digs have unearthed Greek vases from around 500 BC that show a youngster playing with an object similar to the modem yoyo.

Energy-converting machine

For a toy that looks so simple, yo-yos have a fair bit of science governing their operation. It is the physics that is going on that makes it keep spinning for a long time, sleep or hang at the end of the string and climb back up again. Putting it simply, yo-yos are energy-converting machines. The working of yo-yos therefore involves the constant changes of energy from one kind to another.

When held in our hands, a yo-yo has potential energy as it is held high above the floor. When we release the yo-yo, the potential energy is converted to kinetic energy gradually. By the time a spinning yo-yo is at the bottom of the string, it converts all the potential energy it originally held to kinetic energy.

A tug is all it takes

When it climbs back up the spring, it does the reverse, converting kinetic energy to potential energy. While this is similar to a pendulum bob, what makes it different and keeps it going is the fact that we can keep giving it more energy to play around with. By tugging at the string that we are holding, a yo-yo can be kept moving along the string for a considerable amount of time, stopping eventually due to friction and air resistance.

Despite being played with through much of history, yo-yos really exploded in popularity in the 20th Century. And that happened when it was mass-produced and marketed heavily in the U.S., leading to widespread adoption and usage throughout the world.

The first recorded reference to any type of yo-yo in the U.S. came only in 1866, when Ohio tinkerers James Haven and Charles Hettrich came up with a design improvement. Their patent on November 20, 1866 has an image of a whirlgig and mentions "a new and useful bandelore" (whirlgig and bandelore are other names of yo-yo).

This patent is important not only because yo-yos were making their official foray into the U.S., but also for a couple of other reasons. For one, it was the first time rim-weighting was employed to maintain momentum as the patent "marginal swell... exercises the function of a flywheel". Secondly, it also showed that patents can be used to protect design improvements in toys.

Flores calls it yo-yo

A little over half a century after this, Pedro Flores, a Filipino man, sold hand-carved yo-yos in California and staged demonstrations to show how they worked in the 1920s. In fact, it was Flores who trademarked the name "yo-yo", which is Tagalog for "come come" (Tagalog forms the basis of the national language of the Philippines).

American Donald Duncan was impressed by what he saw Flores doing, and he bought the trademark and even piggybacked on the business model. Apart from having people to demonstrate the toys, Duncan also sponsored contests to garner more interest in the product. By promising greater circulation of newspapers in exchange for free ads for these contests, Duncan set about a new marketing idea in motion. The idea's success meant that Duncan's yo-yos were soon a household name.

In the decades that followed, the Duncan Company dominated the yo-yo industry. In the 1960s, millions of these toys were sold on a yearly basis in the U.S. alone. By 1985, yo-yos became one of the first toys to reach space as it was one of the 11 toys taken into orbit by the Discovery space shuttle. Throughout its long and storied history, yo-yos have thus enjoyed a lot of popularity while also having periods of hibernation - ups and downs similar to how the toy functions.

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What was the Centaur project?

The Centaur upper stage rocket is a family of high-energy rockets that has played a pivotal role in advancing global communications and furthering our knowledge of space. November 27, 1963 is an important day in its history as it marked the first in-flight burn of a liquid hydrogen/ liquid oxygen engine.

When we speak about successful space missions, we generally talk about the results they delivered - the satellites that now orbit the Earth or the probes that gathered invaluable data from other planets. There's a lot of work and plenty of factors, however, that goes into reaching that point. One of them is the upper stage rocket that boosts satellites into orbit and propels probes into space.

Among upper stage rockets, Centaur is a significant achievement as it has served as America's workhorse in space and has been involved in many success stories. Used for over 100 unmanned launches, Centaur has expanded the frontiers of space and revolutionised communication.

Where it all began

Centaur’s beginnings predate even the existence of NASA as the U.S. Air Force studied a proposal from General Dynamics/ Astronautics Corp. to develop a new booster stage in 1957. With the space race between the U.S. and the Soviet Union heating up during this period, the idea was to give the country an edge, providing a means of orbiting heavy payloads in a very short time.

In 1958, the year NASA was established, Centaur became an official hardware programme with the Air Force as its assigned development authority. While the heaviest Soviet satellite orbiting the Earth at this time was the 1,360-kg Sputnik III, the U.S. had plans for boosting payloads to up to 3,850 kg. They planned to achieve this using Centaur, which was to have a new propulsion system using liquid hydrogen, mixed with liquid oxygen.

By July 1959, Centaur moved from the jurisdiction of the Department of Defense to NASA. Centaurs planned schedule of testing and operation, however, proved too optimistic, as there were a mountain of problems, failures, and delays to overcome.

Silverstein provides the silver lining

In 1962, American engineer Abe Silverstein put his hand up and convinced NASA that his Lewis Research Center could debug the Centaur and manage its problems. Once the entire responsibility was assigned to Lewis under Silverstein, the Lewis engineers got to work, perfecting the booster, while carrying out complex research and development to ensure Centaurs reliability. The fact that Lewis had been involved in pioneering work on high-energy liquid propellants for rockets helped, as this meant that most engineers working with Centaur were already aware of safely handling the liquid hydrogen/ liquid oxygen cryogenic fuels that it used.

The original Centaur rocket measured 30 feet long and 10 feet in diameter. As it used very cold propellants (liquid oxygen at-297 degrees Fahrenheit and liquid hydrogen at -420 degrees Fahrenheit), its tanks required special construction. A doubled walled bulkhead not only served as a heat barrier, but also separated the two compartments containing liquid hydrogen and liquid oxygen. Made of stainless steel less than 200ths of an inch thick, the tank was extremely thin and light-weight even once pressurised.

Following successful assembly, inspection, and shipping to Cape Canaveral, engineers and technicians perform testing procedures that can last weeks. A special tiger team uses a checklist to go through it all once again in the days leading up to any launch, before putting the rocket into start condition for the flight.

Go Centaur!

On November 27, 1963, one such launch took place. While it only carried a dummy payload that was put into orbit, it was a significant milestone. This was NASA's first successful launch of the Atlas Centaur, proving the compatibility of the Atlas rocket with the upper stage Centaur. Additionally, it had the first in-flight burn of a liquid hydrogen/liquid oxygen engine, showing that these could be safely fired in space. In the decades that followed, there were many more successes for Centaur and a few mishaps too. Centaur was involved in sending the unmanned Surveyor spacecraft, which collected data on the moon's surface and paved the way for the Apollo missions. Along with Atlas and Titan boosters, Centaur featured as the upper for probes and flybys to all other planets in our solar system.

It didn't stop there as Centaur also launched orbiting observatories that help expand our knowledge about the universe, peering at space beyond our solar system. Centaur was also involved in launching various satellites into geosynchronous orbits that have changed the face of communication on our planet. While its name might not be often mentioned along with successful missions, Centaur continues to be a workhorse that serves its purpose.

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What was invented in 1888 by George Eastman?

On September 4, 1888, American inventor George Eastman received a patent for "new and useful improvements" in cameras. On that same day, Eastman also registered the trademark for the name Kodak, a word now synonymous with photography.

What do you, or anyone for that matter, do when you need to capture a moment? You pick up a smartphone, open the camera app, try to best fit the moment you are capturing inside the frame, and tap on the button on the screen to click a photograph. It is as simple as that. With more and more people carrying smartphones these days and with even the basic models boasting a decent camera, amateur photography has been revolutionised like never before.

The first such massive change that promoted amateur photography on a large scale came about in 1888 with the advent of the first Kodak camera. A simple box camera pre-loaded with a 100-exposure roll of film, it made photography less cumbersome than ever before. The man who made it possible was American inventor George Eastman.

Born in 1854 in upstate New York, Eastman had humble beginnings. His father's death meant that he had to drop out of high school while still a teenager in order to support his family. Starting out as a messenger boy earning $3 a week, he went on to be hired as a junior clerk earning $15 a week at the Rochester Savings Bank in 1874.

The trip that didn't happen

It was in that same year that he was drawn towards photography. When he made travel plans, a colleague suggested that Eastman record his trip using a "photographic  outfit”. Even though he eventually didn't make the trip, Eastman had purchased the "outfit and described it as "a pack-horse load”.

Apart from the fact that the camera was heavy and needed a tripod, Eastman would have also had to carry a tent and loads of equipment to develop the photographs if he had gone on the trip. Soon, Eastman was obsessed with the idea of making photography easier.

A company is born

Still holding on to his job at the bank, Eastman spent countless evenings and nights toiling away towards a solution. Realising that wet plates definitely weren't the way forward, Eastman invented and patented a dry plate formula. He went into the photographic business on a full-time basis, and the Eastman Dry Plate and Film Company was born.

More innovations followed as he began to look for new exposure methods. In order to replace the glass plates, he first came up with a light-sensitive, gelatin-coated paper that could be rolled onto a holder.

In 1888, Eastman introduced the first Kodak camera, which proved to be the first successful roll-film hand camera that came in a compact box with 100 exposures' worth of film. As the paper proved problematic, Eastman, along with young research chemist Henry  Reichenbach, experimented further until they hit upon the possibility of flexible rolls of sensitised celluloid. At around the same time, another American Hannibal Goodwin independently arrived at celluloid-based camera films, resulting in lengthy patent wars between the parties that was belatedly settled in Goodwin's favour.

On September 4, 1888, just months after the public release of the camera, Eastman received a patent for "new and useful improvements" in cameras. That very day. Eastman also registered the trademark for the Kodak name.

"We do the rest"

Bolstered by the introduction of the film rolls, the Kodak cameras became a runaway success. An advertising campaign was introduced with the slogan "You press the button, we do the rest." This was exactly how things panned out as users sent the entire camera back to the manufacturer for developing, printing, and reloading once the film was entirely used up.

Quick to spot an opportunity, Eastman changed the name of his company from Eastman Dry Plate and Film Company to Eastman Kodak Company in 1892. By the time he died aged Eastman Kodak dominated the industry in the U.S. and across the world. It still remains one of the best recognised names in the field, with the word Kodak becoming synonymous to photography.

Apart from being an inventor and innovator, Eastman was also far ahead of his time in various other ways. As a philanthropist, Eastman gave away much of the fortune that he created while still alive to many beneficiaries, including universities. As a businessman, he was among the first to introduce profit sharing as an incentive to employees. But then, he will forever be remembered as the one who placed the power of photography within the grasp of anyone who could just press a button. That button is now more accessible than ever before.

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Who was the father of popular science fiction?

English writer H.G Well is considered one of the great fathers of science fiction, for developing and popularising the genre. Let us look at his novella The Invisible Man and see what makes it relevant today.

About the author

Herbert George Wells one of the fathers of modern science fiction (sci-fi) was born on September 21, 1866, in Bromley. England. He was the youngest of four children of Joseph (Joe) Wells, a gardener and cricketer-turned-shopkeeper, and his wife Sarah.

Wells had been a voracious reader from a very early age. When a broken leg immobilised him at the age of seven, the adventures his paperbound friends offered became his favourite pastime. By the time he was 13. he had already finished his first literary work The Desert Daisy, all the while excelling in school But growing up in a financially impoverished household he had to stop his formal education at the age of 14 and was employed (with his two elder brothers) to become an assistant to a draper and contribute to his family's income. When he was fired by his first employer, he became an assistant to a chemist. This was followed by an apprenticeship under another draper, till he won a scholarship to study biology at the Normal School of Science in London at the age of 18. There he met T.H. Huxley, a vocal supporter of Darwinism and a person who will instil a love for zoology and set him up for the next stage of his life.

In school, he dedicated most of his time to literature and politics. It was during this phase of his life that he started writing in the genre we identify as science fiction and wrote The Chronic Argonauts, a story that would later turn into one of his most celebrated books, The Time Machine (1895).

The scientific romance

The Time Machine was the first example of what Wells called scientific romance. This was a blend of serious social and scientific commentary intricately woven with a fast pace entertaining page-turner. These scientific romances laid the foundation for the modem sci-fi genre.

What makes it a classic?

The individual and the society

The end of the novella reveals that Griffin is an albino, who was shunned by his fellows in university because he looked different. It is this rejection and society's inability to look past his physical difference to the intelligent man within, that has instigated his turn to the bad side.

Griffin's story can also be seen as a parable that educates the readers to debate the role society plays in creating the evils that plague it.


Jamaican-born Canadian speculative fiction writer Nalo Hopkinson defines sci-fi as "that branch of literature that deals with the consequence of humanity's use of tools for manipulating nature". In Griffin's case, this need to manipulate oneself physically stems from the bitterness and cruelty he faced growing up and stands as a metaphor for how insubstantial and worthless people have made him feel of his appearance.

The story's resolution with the death of the invisible man can also be seen as moral symbolising the detriments of using science and technology for selfish means instead of the betterment of the world.

The art of education

The hallmark of Well's 50-year writing career is the lesson his stories entail. He would always say that he recognised himself as a teacher and a journalist before an artist. According to him, the function of art was to educate and enrich the lives of the people it comes in contact with.

Professor Simon James from the Department of English Studies at Durham University says that "Education is Well's panacea (universal cure) for the social divisions that he sees in the world he inhabits. It's about seeing the world in an informed way that allows you to address it and fix it and try to make it better." Well's use of sci-fi to address anxieties of the world regarding the extraordinary development of technology, to reflect on the nature and essence of humanity, and explore how we understand each other, is what makes him stand out from his peers as the indispensable proponent of the genre.

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What did Wilhelm Roentgen discover that helped with surgery?

Discovered in 1895 by German physicist Wilhelm Roentgen, X-ray revolutionised the fields of physics and medicine.

An X-ray is a kind of electromagnetic radiation that can travel at the speed of light (299.792 km per second) and pass through most substances including wood, tin foil, books and even concrete blocks that ordinary light cannot penetrate. It was discovered in 1895 by German physicist Wilhelm Roentgen.

Roentgen was experimenting with cathode rays, when he noticed that the fluorescent screen had begun to glow although no light was falling on it. He realised that it was due to an invisible ray. He called it X-ray because he did not really know what it was. Later, his colleague named it Roentgen ray.

The discovery of X-rays revolutionised the fields of physics and medicine.

As it can make internal structures of the body visible, X-rays are used to detect bone fractures, dental cavities, tumours, etc.

The flip side of the X-ray is that it can cause biological, chemical and physical changes in substances. It can damage the living tissues of plants and animals if it is absorbed by them. In human beings, an X-ray overdose may produce cancer, skin burns, a reduction of blood supply and other serious conditions.

Today we have a wide range of medical imaging techniques to create visual representations of the internal body. These include CT (computed tomography) scans, MRI (magnetic resonance imaging) and ultrasound.

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