Albert Einstein visual arts exhibition


This is a video about a 2008 exhibition in the Lakenhal and Boerhaave museums in Leiden, the Netherlands about the Kamerlingh Onnes family. Some people in that family were physicists (with a special interest in cold temperatures), some were visual artists.

Albert Einstein, 1920 drawing by Harm Kamerlingh Onnes

Translated from NOS TV in the Netherlands:

Albert Einstein in Leiden museum

Today, 19:23

Leiden artist Harm Kamerlingh Onnes (1893-1985) has portrayed twenty renowned scholars in the years when they visited his uncle, the Nobel Prize winner Heike Kamerlingh Onnes. Among them was Albert Einstein. Boerhaave Museum in Leiden has now acquired these sketches and drawings. The majority was not known until now.

Harm was in 1920 and 1921 also regularly found in the laboratory of his uncle Heike, who was doing research on absolute zero temperature (-273 ° C). He made portraits and recorded how his uncle and staff were busy with their experiments.

Houseguests

The physicist Heike Kamerlingh Onnes received the Nobel Prize in 1913. In his Leiden home, Huize ter Wetering at the Galgewater, at that time many foreign guests visited.

The house was a meeting place for scholars and artists, including Marie Curie, Albert Einstein and Niels Bohr. They met there Dutch artists like Jan Toorop, Albert Verwey and Carel Lion Cachet.

Exhibition

The collection of drawings is from the estate of a son of Harm Kamerlingh Onnes. A selection will be on show from 21 February until 26 April at the Museum Boerhaave in Leiden. About the family of scientists and artists an accompanying booklet has been published with the title Koude, kunst, Kamerlingh Onnes [Cold, art, Kamerlingh Onnes], written by Dirk van Delft.

See also here. And here.

How hummingbirds hover, new research


This video from the USA says about itself:

Realistic aerodynamic simulation reveals how hummingbirds hover

21 November 2014

The most detailed aerodynamic simulation of hummingbird flight conducted to date demonstrates that it achieves its aerobatic abilities through a unique set of aerodynamic forces more closely aligned to those found in flying insects than in other birds. The simulation was produced by Vanderbilt engineers working with a biologist from the University of North Carolina at Chapel Hill.

From Wildlife Extra:

Secret behind hummingbird aerobatic feats discovered

Just how tiny hummingbird[s] can hover in front of a flower before darting to another has always puzzled scientists.

But new research shows that this ability is more closely related to those found in flying insects than to other birds.

A three-dimensional aerodynamic simulation demonstrated that the tiny birds make use of unsteady airflow mechanisms to generate invisible vortices of air that produce the lift they need to hover and flit from flower to flower.

When a bird pulls its wings forward and down, tiny vortices form over the leading and trailing edges and then merge into a single large vortex, forming a low-pressure area that provides lift. The tiny hummingbird[s] further enhance the amount of lift they produce by pitching up their wings (rotate them along the long axis) as they flap.

However, unlike most birds, hummingbirds are also able to generate lift on the upstroke by inverting their wings. As the leading edge begins moving backwards, the wing beneath it rotates around so the top of the wing becomes the bottom and bottom becomes the top. This allows the wing to form a leading edge vortex as it moves backward generating positive lift.

Although hummingbirds are much larger than flying insects and stir up the air more violently as they move, the way that they fly is more closely related to insects than it is to other birds, according to the researchers. Insects like dragonflies, houseflies and mosquitoes can also hover and dart forward and back and side to side.

The new realistic simulation (see film above) demonstrates that the tiny birds make use of unsteady airflow mechanisms, generating invisible vortices of air that produce the lift they need to hover and flit from flower to flower.

‘European Union blames migratory birds unfairly for bird flu’


This video is called Physics of Bird Migration.

Translated from NOS TV in the Netherlands:

Migratory birds are an easy scapegoat

Tuesday 18 Nov 2014, 20:47 (Update: 18-11-14, 21:02)

Prominent scientists doubt that the latest variant of avian influenza is brought to Western Europe by migratory birds. The theory of the spread by migratory birds was yesterday published more or less as an established fact by poultry experts of the European Commission.

According to Henk van der Jeugd of the Dutch Institute of Ecology (NIOO-KNAW) in Wageningen there is still too little known to draw conclusions. “Migratory birds are an easy scapegoat,” he says. “If migratory birds brought the virus, then we would have to find it in wild birds in the vicinity of the affected captive bird business.” But that has not been done yet.

He thinks the facts should be investigated thoroughly. “Otherwise no effective measures can be taken.” …

Mallards

Because migratory birds were designated as disseminators of the virus, according to Van der Jeugd other possibilities were neglected. For example, migratory birds may become infected by native birds, instead of the other way round.

Last month a NIOO study about ducks in the Netherlands showed that migratory wild mallards here get a mild form of bird flu from native ducks, which have the virus, but do not themselves become ill.

See also here.

Galileo Galilei and the beginning of physics


This video says about itself:

Galileo (1975) – Joseph Losey (1)

This bio-film is based on Bertold Brecht‘s play about Galileo Galilei, the 17th century Italian who laid the foundations of modern science. Galileo made himself one of the world’s first telescopes and discovered the moons of Jupiter.

He supported Copernicus’ theory that the Earth revolved around the Sun. This brought him in conflict with the Catholic Church. By threatening him with torture, the Church forced him to recant his views in front of a tribunal, and sentenced him to house arrest. However, Galileo’s trials and theories inspired others like Newton and Kepler to prove that the Earth was not the centre of the Universe. Some years ago, the Pope accepted that Earth does revolve around the Sun and issued a rare apology for what the Church had done to Galileo, i.e., the Catholic Church recanted.

By Henry Allan and Bryan Dyne:

The beginning of modern physics

9 September 2014

Renaissance Genius: Galileo Galilei and His Legacy to Modern Science, David Whitehouse, Sterling, 2009 (US $24.95)

This volume is a welcome contribution to the study of the Italian Renaissance, written by the British archeologist David Whitehouse. It gives a comprehensive view of the world of the Italian Renaissance at a time when ideas, discoveries and new inventions accelerated the clash of science with the medieval institution of the Roman Catholic Church. The book’s primary focus is the life and work of Galileo Galilei (1564-1642), whose persecution by the Church reflects the tribulations of most of the progressive thinkers of the time.

The book was published to coincide with the 400th anniversary of the year when Galileo turned his significantly improved version of the telescope to the night skies and began to draw the phases of the moon. It is lavishly illustrated with paintings, photographs, and illustrations that depict the time in which Galileo lived, his life, friends, colleagues, adversaries and persecutors.

As Renaissance Genius shows, this was the time of the Inquisition and its imprisonment, torture, and heinous executions of those deemed “heretics.” This included anyone who challenged existing church doctrine, particularly those developing the new techniques of observation, experimentation and the combination of the two with mathematics. Among those persecuted were Giordano Bruno, Antonio de Dominis and Galileo himself.Galileo Galilei

Vincenzo Galilei, Galileo‘s father, was a mathematician and music theorist who challenged traditional beliefs in the infallibility of Greek philosophic thought backed by both church and state. He found, for example, that the practical application of experimentation disproved long-held beliefs of the ancient Greek philosopher Pythagoras on musical interval and pitch between two strings. Pythagoras had held that in the tuning of strings, the weights used to stretch the strings, the tension must be doubled. It turned out that in practice, the tension had to be quadrupled, not doubled, to produce a tone an octave higher. As Whitehouse explains:

“It is hard to underestimate the importance of this moment in Galileo’s life. He and his father had found a new harmony; a new set of mathematical laws that correlated the note produced by a string to its tension, and had done so by experiment. They had not looked up the answer in either an ancient Greek treatise nor sought the advice of some musical authority. This was the start of modern science: They had carried out an experiment and asked a question of nature itself. It was revolutionary. Vincenzo’s actions had unfolded the course of his son’s life in experimental physics.”

Later in life, Galileo would use experimental techniques to show that objects fall towards the Earth at the same rate, regardless of mass. That some objects seem to fall slower is because of air resistance, not a property of the objects themselves. This challenged the Aristotelian principle that claimed that heavier objects fall faster than lighter ones. The most famous of these experiments was done at the Leaning Tower of Pisa, when he released two identically shaped spheres of different masses from the top of the tower. The spheres, one of 100 pounds and the other only one pound, hit the ground at the same time.

Nearly 400 years later, astronaut David Scott of Apollo 15, carried out a similar experiment on the surface of the moon, releasing a feather and a metal hammer. Both struck the lunar surface at the same time. “Galileo was correct,” exclaimed Scott.

This video is called APOLLO 15 Hammer and Feather.

Galileo’s achievements also involve a number of inventions related to other fields of science. He developed the thermoscope, the predecessor of the thermometer, which was the first attempt to measure heat. The Venetian Senate awarded him a patent for a water-lifting machine used in irrigation that only used one horse. A friend in the tool-making trades helped Galileo develop a simple compass that could be used to gauge the distance and height of a target as well as measure the angle of elevation of a cannon’s barrel. While Galileo did not invent the telescope, which was first built in the Netherlands in 1608, he is credited with increasing the magnification by 20 to 30 times using advanced lens-crafting techniques.

His interest in telescopes was sparked in 1604 when a new “star” appeared in the constellation Ophiuchus. This followed an earlier appearance of a new star in 1572 that was studied by the Danish astronomer Tycho Brahe. Such occurrences challenged the long-held notion of both the Aristotelians and the Church that the heavens are perfect and unchanging. Always being one to pursue observations, Galileo sought a way to study the night sky in greater detail.

One of Galileo's early telescopes at the Museum of the History of Science in Florence, Italy

With his telescope, he began to paint the different phases of the moon and its observable dark and light spots. He showed the moon to his patron, the Duke of Tuscany, who was delighted. Galileo then observed the Pleiades star cluster, as well as the planet Jupiter. Through these observations, he discovered the four largest moons of Jupiter – Io, Callisto, Europa and Ganymede, and provided the first evidence of objects orbiting a body other than the Earth. This was the proof Galileo needed to become a fervent advocate of the Copernican model of the cosmos.

A similar realization was made during Galileo’s study of the phases of Venus, repeating in much greater detail observations done by Copernicus. After recording the pattern of sunlight reflected from Venus’ atmosphere, he realized that the only way such patterns could occur is if both Venus and Earth revolved around the Sun. Galileo published a book on his observations, which circulated throughout Europe.

Included in his observations were the recording of sunspots. By aiming the telescope at the Sun and letting the light pass through the telescope onto a white background, Galileo was able to sketch out the positions of sunspots and determine that such imperfections on the Sun both existed and changed with time. Both this observation and the experimental evidence that the Earth is not the center of the universe incurred the wrath of the Church.

Galileo before the Holy Office, painted by Joseph-Nicolas Robert-Fleury

Both the Greek philosopher Aristotle and the Vatican considered the sun a perfect and unblemished sphere. The stars themselves were seen as divinities, contributing to the growth of astrology. It was argued by church supporters that the observed sunspots must be satellites of the sun and not “imperfections” in its surface. Galileo stated that not only were sunspots on the surface of the sun, they changed their shapes, and both originated and dissolved on that sphere. This could only lead to one conclusion: the sun was not a perfect sphere.

Galileo’s popularity and a newly established science academy in Rome ensured the continued publication of his works and a certain defense against the Church and other professional enemies. However, the issue of sunspots became the spark for an open clerical attack upon Galileo.

The story of how this debate unfolded is but one example of how the church and its privileged office-holders used the Bible to defame scientists like Galileo. Galileo himself believed that nothing that was discovered in any way conflicted with Scripture and quoted an ecclesiastical historian, Cardinal Baronius (1538-1607), who had commented: “The Holy Ghost intended to teach us how to go to heaven, not how the heavens go.” This clever riposte did not save him. As Whitehouse points out:

“In his innate conservatism, Cardinal Bellarmine saw the Copernican universe as threatening to the social order. To him and to much of the Church’s upper echelon, the science of the matter was beyond their understanding — and in many cases their interest. They cared more for the administration and the preservation of Papal power than they did for getting astronomical facts right.”

In the end, Galileo was told by Bellarmine and the head of the Inquisition, Cardinal Agostino Oreggi, that Copernicus’ views were wrong and he was not to support them. Furthermore, he was ordered not to teach or defend Copernican theory in any way, either in his writings or verbally.

After Bellarmine and Pope Paul V died, Galileo still harbored great hopes that the new Pope, Urban VIII, his former friend Maffeo Barberini, would prove when elected to be much better than his predecessors. This was an illusion. He was summoned before an even more hostile Inquisition than the first time.

While Whitehouse speculates that for Barberini, being Pope “had gone to his head,” the more fundamental truth is, as he observed earlier, that the Church hierarchy as a whole viewed “the Copernican universe as threatening to the social order.” The Pope, no matter his individual origins, was bound by his place in medieval society to defend the status quo.

The reproductions in Whitehouse’s book of paintings and illustrations depicting book burnings, the burnings at the stake for heresy, and the humiliations endured by thousands at the hands of the Inquisition reinforce this point.

Renaissance Genius depicts how Galileo’s defense of the Copernican system and the subsequent discoveries by Kepler, Rene Descartes, and Isaac Newton not only established the beginnings of physics, but also led to the advances for science that have resulted in the modern space program, including the space probe named after Galileo and the Hubble space telescope, the most extraordinary advance in the technology which Galileo pioneered.

Whitehouse sums up the Galilean revolution by providing us with a very human portrait of the man, the history of his times and Galileo’s indispensable role in the advancement and popularization of science for humankind.

Richard Feynman’s physics lectures on the Internet


This video from the USA is called Richard Feynman – The.Character of Physical Law – Part 1 The Law of Gravitation (full version) — An Example of Physical Law.

Lecture 2: The Relation of Mathematics and Physics.

Lecture 3: The Great Conservation Principles.

Lecture 4: Symmetry in Physical Law.

Lecture 5: The Distinction of Past and Future.

Lecture 6: Probability and Uncertainty — The Quantum Mechanical View of Nature.

Lecture 7: Seeking New Laws.

By Robbie Gonzalez today:

You Can Now Access All Of Richard Feynman’s Physics Lectures For Free

The lectures of Nobel Prize winning physicist Richard Feynman were legendary. Footage of these lectures does exist, but they are most famously preserved in The Feynman Lectures. The three-volume set may be the most popular collection of physics books ever written, and now you can access it online, in its entirety, for free.

The complete online edition of The Feynman Lectures on Physics has been made available in HTML 5 through a collaboration between Caltech (where Feyman first delivered these talks, in the early 1960s) and The Feynman Lectures Website. The online edition is “high quality up-to-date copy of Feynman’s legendary lectures,” and, thanks to the implementation of scalable vector graphics, “has been designed for ease of reading on devices of any size or shape; text, figures and equations can all be zoomed without degradation.”

Volume I deals mainly with mechanics, radiation and heat; Volume II with electromagnetism and matter; and Volume III with quantum mechanics.

Go. Have fun.

Starling murmurations, new research


This video is about a starling murmuration in Britain.

From Science:

How bird flocks are like liquid helium

By Marcus Woo

27 July 2014 1:00 pm

A flock of starlings flies as one, a spectacular display in which each bird flits about as if in a well-choreographed dance. Everyone seems to know exactly when and where to turn. Now, for the first time, researchers have measured how that knowledge moves through the flock—a behavior that mirrors certain quantum phenomena of liquid helium.

“This is one of the first studies that gets to the details of how groups move in unison,” says David Sumpter of Uppsala University in Sweden, who was not part of the study.

The remarkable accord with which starling flocks fly has long puzzled researchers and bird watchers alike. In the 1930s, the ornithologist Edmund Selous even suggested that the birds cooperate via telepathy. Researchers have since turned to more scientifically sound ideas, using mathematical models.

In the 1990s, physicist Tamás Vicsek of Eötvös Loránd University in Budapest came up with one of the more successful models, which is based on the principle that each bird flies in the same direction as its neighbors. If a bird angles right, the ones next to it will turn to stay aligned. Although this model reproduces many features well—how a flock swiftly aligns itself from a random arrangement, for example—a team of researchers from Italy and Argentina has now discovered that it doesn’t accurately describe in detail how flocks turn.

In their new study, the team, led by physicists Andrea Cavagna and Asja Jelic of the Institute for Complex Systems in Rome, used high-speed cameras to film starlings—which are common in Rome and form spectacular flocks—flying near a local train station. Using tracking software on the recorded video, the team could pinpoint when and where individuals decide to turn, information that enabled them to follow how the decision sweeps through the flock. The tracking data showed that the message to turn started from a handful of birds and swept through the flock at a constant speed between 20 and 40 meters per second. That means that for a group of 400 birds, it takes just a little more than a half-second for the whole flock to turn.

“It’s a real tour de force of measurement,” says Sriram Ramaswamy of the Tata Institute of Fundamental Research’s Centre for Interdisciplinary Sciences in Hyderabad, India, who wasn’t part of the research.

The fact that the information telling each bird to turn moves at a constant speed contradicts the Vicsek model, Cavagna says. That model predicts that the information dissipates, he explains. If it were correct, not all the birds would get the message to turn in time, and the flock wouldn’t be able to fly as one.

The team proposes that instead of copying the direction in which a neighbor flies, a bird copies how sharply a neighbor turns. The researchers derived a mathematical description of how a turn moves through the flock. They assumed each bird had a property called spin, similar to the spins of elementary particles in physics. By matching one another’s spin, the birds conserved the total spin of the flock. As a result of that conservation, the equations showed that the information telling birds to change direction travels through the flock at a constant speed—exactly as the researchers observed. It’s this constant speed that enables everyone to turn in near-unison, the team reports online today in Nature Physics.

The new model also predicts that information travels faster if the flock is well aligned—something else the team observed, Cavagna says. Other models don’t predict or explain that relationship. “This could be the evolutionary drive to have an ordered flock,” he says, because the birds would be able to maneuver more rapidly and elude potential predators, among other things.

Interestingly, Cavagna adds, the new model is mathematically identical to the equations that describe superfluid helium. When helium is cooled close to absolute zero, it becomes a liquid with no viscosity at all, as dictated by the laws of quantum physics. Every atom in the superfluid is in the same quantum state, exhibiting a cohesion that’s mathematically similar to a starling flock.

The similarities are an example of how deep principles in physics and math apply to many physical systems, Cavagna says. Indeed, the theory could apply to other types of group behavior, such as fish schools or assemblages of moving cells, Sumpter says.

Other models, such as the Vicsek model or others that treat the flock as a sort of fluid, probably still describe flock behavior over longer time and length scales, Ramaswamy says. But it’s notable that the new model, which is still based on relatively simple principles, can accurately reproduce behavior at shorter scales. “I think that’s cool,” he says. “That’s an achievement, really.”

Sumpter agrees. “It’s kind of reassuring we don’t need to think about the telepathic explanation,” he says.

See also here.