299 episodes

Explorations in the world of science.

Discovery BBC

    • Science
    • 4.1, 7 Ratings

Explorations in the world of science.

    Helium

    Helium

    Andrea Sella, Professor of Inorganic Chemistry at University College London, celebrates the art and science of the chemical elements. Today he looks at helium.

    Helium is a finite resource here on Earth and many branches of science need it. Doctors need it to run MRI machines to diagnose tumours and engineers test rockets for leaks with it.

    The story of helium starts with a solar eclipse in 1868. The event had many astronomers' eyes fixed on the sun. Two astronomers, nearly simultaneous and independently, made the same observation; a strange light with an unusual wavelength coming from the sun. It turned out to be the first sighting of extra-terrestrial helium. It would take decades for helium to be discovered on Earth and longer still for its worth to be recognised.

    As its ability to make things float and inability to burn became apparent, the US military started hoarding it for their floating blimps. But they soon realised that it is very hard to store an element that is so light that it can escape the Earth's gravitational pull. As we empty our last reserves of the periodic table's most notorious escape artist – is the future of helium balloons, often used to mark special events, up in the air?

    • 26 min
    The Evidence: Covid 19: Sub-Saharan Africa and Testing

    The Evidence: Covid 19: Sub-Saharan Africa and Testing

    Claudia Hammond and a panel of international experts look at the latest research into Covid-19, the disease caused by the new coronavirus which is sweeping through the world. As the disease spreads how is sub-Saharan Africa handling the pandemic? We also look at tests – how accurate are they? Should we be testing ourselves at home? On the panel are Folasade Ogunsola, Professor of Clinical Microbiology at the University of Lagos in Nigeria, Ravi Gupta, Professor of Microbiology at the University of Cambridge’s Department of Medicine, Matthew Fox, Professor of Epidemiology and Public Health at Boston University and Dr Margaret Harris, a Spokesperson at the World Health Organisation.

    The Evidence is produced in association with Wellcome Collection. Producers: Geraldine Fitzgerald and Caroline Steel Editor: Deborah Cohen

    • 49 min
    Aluminium and strontium

    Aluminium and strontium

    Andrea Sella, Professor of Inorganic Chemistry at University College London, celebrates the art and science of the chemical elements. Today he looks at aluminium and strontium, elements that give us visual treats.

    At the time of Emperor Napoleon the Third in 19th century France aluminium was more valuable than gold and silver. The Emperor liked the metal so much he had his cutlery made out of it. But once a cheaper way was discovered to extract aluminium it began to be used for all kinds of objects, from aeroplanes to coffee pots. Andrea talks to Professor Mark Miodownik at the Institute of Making at UCL about why aluminium is such a useful material, from keeping crisps crisp to the tinsel on our Christmas trees. And he talks about the lightness of bicycles made from aluminium with Keith Noronha, of Reynolds Technology.

    Strontium is the 15th most common element in the earth yet we really only come into contact with it in fireworks. It gives us the deep red colour we admire in a pyrotechnics display. Andrea meets Mike Sansom of Brighton Fireworks who explains how a firework is constructed and reveals the chemical mix that creates the bright red flashes.

    Professor Thomas Klapötke of the Ludwig-Maximilians University in Munich talks about his search for a substitute for strontium in fireworks and about how the element can get into our bones. Rupert Cole at the Science Museum in London shows Andrea how Humphry Davy was the first to extract strontium from rocks found in Scotland.

    And Janet Montgomery, Professor of Archaeology at Durham University, explains how strontium traces have revealed that our Neolithic ancestors moved around much more than was previously thought. Nearly half the people buried around Stonehenge in Southern England were born in places with different rocks from those under Salisbury Plain in Southern England.

    Picture: Fireworks, credit: rzelich/Getty Images

    • 26 min
    Gold and silver

    Gold and silver

    Andrea Sella, Professor of Inorganic Chemistry at University College London, celebrates the art and science of chemical elements. In this episode he looks at two elements we have valued for millennia – gold and silver.

    Nina Gilbey at the London Jewellery Workshop teaches him how to work the metal and make a silver ring, and Rupert Cole, Curator of Chemistry at the Science Museum, shows him the handiwork of silversmiths who fashioned an elaborate microscope for King George the Third and a silver thimble that was used (with some zinc and a few drops of an acid) to generate an electric current that was sent through a transatlantic telegraph cable in 1866. And Andrea finds out about silver's anti-bacterial properties from Jean-Yves Maillard, Professor of Pharmaceutical Microbiology at Cardiff University.

    For the Egyptians gold was the ultimate symbol of wealth, power and eternal life. For this reason they buried their Pharaohs with extraordinary amounts of gold artefacts. As a noble metal, gold doesn’t tarnish which added to its status and association with the sun god Ra and the afterlife. Andrea talks to Professor Marcos Martinon-Torres of Cambridge University at an exhibition of Tutankhamun’s riches, and to Professor Lynne Macaskie of Birmingham University about ways to recycle gold from our electronic waste using bacteria. The method offers a greener way to satisfy our lust for gold.

    Picture: Gold and silver bracelets, Credit: krfletch/Getty Images

    • 27 min
    The Evidence: Covid 19: ending lockdowns

    The Evidence: Covid 19: ending lockdowns

    Claudia Hammond and her panel of scientists and doctors analyse the latest science on the coronavirus and answer the audience’s questions on the impact of the pandemic.

    Dr Lucy van Dorp of UCL explores the genetics of the virus and what they can tell us about how far it’s spread and how is it evolving. Can we be sure that vaccines being developed now will still work in the future? Professor Guy Thwaites of the Oxford University Clinical Research Unit in Vietnam explains how the country has succeeding in keeping its cases so low. Professor David Heymann of the London School of Hygiene and Tropical Medicine and Professor Ngaire Woods, of the Blavatnik School of Government at Oxford University, tackle the question that people all around the world are wondering right now – how does a country safely emerge from lockdown without seeing a surge in cases?

    And Professor Lisa Cooper of Johns Hopkins University in Baltimore and family doctor and Director of the Shuri Network, Dr Shera Chok, discuss why black and other ethnic minorities in the US and UK seem to be so disproportionately impacted by Covid 19.

    The Evidence is produced in association with Wellcome Collection.

    Producers: Geraldine Fitzgerald and Caroline Steel
    Editor: Deborah Cohen

    • 50 min
    Science of Dad

    Science of Dad

    Whilst most men become fathers, and men make up roughly half the parental population, the vast majority of scientific research has focused on the mother.

    But studies have started to reveal the impact of fatherhood on both dads themselves and on their children. We're seeing how fathers play a crucial role in children's behaviour, happiness, and even cognitive skills.

    Oscar Duke, a doctor, new dad and author of How To Be A Dad, discovers how pregnancy, birth and childcare affect the father, bringing about profound physiological and hormonal changes. Only 5% of mammal fathers invest in their offspring, and human males have evolved to undergo key changes when their children are born.

    Involved fathers can expect their levels of the 'love hormone' oxytocin to rise, nature's way of helping parents bond with their children. At birth, a dad's testosterone levels dramatically fall, increasing affection and responsiveness, and discouraging polygamy.

    With more fathers taking on a hands-on role in bringing up their children, how can these new discoveries about the science of dad help support them, and inform social and healthcare policies?

    Presented by Dr Oscar Duke and produced by Melanie Brown and Cathy Edwards

    • 27 min

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