#lawrence bragg

[ri-science]

PhD student Sarah Madden dug through our collections to learn more about the history of crystallography. Read about her experience below.

I’m a PhD student working in cancer research at the University of Cambridge, and currently work as the Media and Communications Assistant at the Royal Institution. 

One of my favourite days of my time here was getting to look through the archives with the Ri’s lovely curator of collections, Charlotte. Being the self-confessed crystallography geek that I am, Charlotte was kind enough to let me look through the history of X-ray crystallography.

X-ray crystallography is the process of growing crystals of a compound, and then analysing them with X-rays to work out the compound’s structure.

William Henry Bragg and his son, William Lawrence Bragg, were the ‘Fathers’ of X-ray crystallography. Both served as Directors of the Davy-Faraday Research Laboratory at the Royal Institution.

They came up with Bragg’s law, which allows crystallographers to work out the structure of a compound.

We do this by looking at the diffraction pattern generated by by sending X-rays through crystals of the compound with unknown structure.

Lawrence Bragg constantly wrote letters to his father to ask for help with his research, many of which are stored in the Royal Institution’s archives. The father and son team were awarded the Nobel Prize for Chemistry in 1915. Lawrence was only 25 at the time and was withdrawn from the front line where he was serving as an officer during World War 1.

The collection at the Royal Institution includes a host of Lawrence’s belongings, including his Nobel prize diploma, his photographs of crystal diffraction patterns and his notebook with Bragg’s law written in it.

Watch our full ‘Understanding Crystallography’ video

Learn more about the science and history of crystallography

Follow Sarah on Twitter to see what she gets up to at the Ri and back in her lab at Cambridge: @TheGingerSci

[ri-science]

Double refraction of light through crystalline structures, demonstrated by Sir Lawrence Bragg in 1965.

If you look through glass at some writing, you’ll be able to see it clearly, as normal. But if you look through a clear crystal, like calcite, you’ll see two overlapping images. This is because of the crystal structure.

When light enters water or glass, it slows down uniformly. When it enters a crystal, with it’s very regular pattern, the light is affected differently in two different directions, rather than uniformly in all directions. As a result, the light will split into two beams, travelling at different speeds. This difference in speed means the beams bend, or refract, differently, resulting in two distinct images.

Here, Bragg rotates a polarised sheet above the crystal to reveal only one orientation at a time, showing each image separately in turn:

Watch the full film, with dozens more demonstrations, on the Ri Archives YouTube channel.

[oupacademic]

On the Shelves in Oxford this week are three new science Very Short Introductions!

In Crystallography: A Very Short Introduction by A.M. Glazer introduces the field of crystallography, and explains its basic concepts. 

Computer Science: A Very Short Introduction discusses the core principles of computer science and Introduces the essential idea of automatic computation in the form of the Turing machine. 

James Binney shows how the field of astrophysics has expanded rapidly in the past century and introduces the physics of phenomena such as supernovae in Astrophysics: A Very Short Introduction.

Photos by Yasmin Coonjah for Oxford University Press

[brianbrownnet]

A new article has been published on www.brianbrown.net

New Post has been published on http://www.brianbrown.net/2014/10/11/pakistans-malala-yousafzai-survives-shooting-by-taliban-becomes-youngest/

Pakistan's Malala Yousafzai survives shooting by Taliban, becomes youngest ...

OSLO – Pakistani teenager Malala Yousafzai, who was shot in the head by the Taliban in 2012 for advocating girls’ right to education, and Indian children’s right activist Kailash Satyarthi won the 2014 Nobel Peace Prize on Friday.

With the prize, Yousafzai, 17, becomes the youngest Nobel Prize winner, eclipsing Australian-born British scientist Lawrence Bragg, who was 25 when he shared the Physics Prize with his father in 1915.

Satyarthi and Yousafzai were picked for their struggle against the suppression of children and young people, and for the right of all children to education, the Norwegian Nobel Committee said.

“The Nobel Committee regards it as an important point for a Hindu and a Muslim, an Indian and a Pakistani, to join in a common struggle for education and against extremism,” said Thorbjoern Jagland, the head of the Norwegian Nobel Committee.

“It has been calculated that there are 168 million child laborers around the world today,” Jagland said. “In 2000 the figure was 78 million higher. The world has come closer to the goal of eliminating child labor.”

Satyarthi has headed various forms of peaceful protests and demonstrations, focusing on the exploitation of children for financial gain.

Yousafzai was attacked in 2012 on a school bus in the Swat Valley in northwest Pakistan by masked gunmen as a punishment for a blog that she started writing for the BBC’s Urdu service as an 11-year-old to campaign against the Taliban’s efforts to deny women an education.

Unable to return to Pakistan after her recovery, Yousafzai moved to Britain, setting up the Malala Fund and supporting local education advocacy groups with a focus on Pakistan, Nigeria, Jordan, Syria and Kenya.

The prize, worth about $1.1 million, will be presented in Oslo on Dec. 10, the anniversary of the death of Swedish industrialist Alfred Nobel, who founded the award in his 1895 will.

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