In Our Time: Science

Melvyn Bragg and guests discuss how scientists sought to understand the properties of gases and the relationship between pressure and volume, and what that search unlocked. Newton theorised that there were static particles in gases that pushed against each other all the harder when volume decreased, hence the increase in pressure. Those who argued that molecules moved, and hit each other, were discredited until James Maxwell and Ludwig Boltzmann used statistics to support this kinetic theory. Ideas about atoms developed in tandem with this, and it came as a surprise to scientists in C20th that the molecules underpinning the theory actually existed and were not simply thought experiments. The image above is of Ludwig Boltzmann from a lithograph by Rudolf Fenzl, 1898 With Steven Bramwell Professor of Physics at University College London Isobel Falconer Reader in History of Mathematics at the University of St Andrews and Ted Forgan Emeritus Professor of Physics at the University of Birmingham Producer: Simon Tillotson

Melvyn Bragg and guests discuss theories about the origins of teeth in vertebrates, and what we can learn from sharks in particular and their ancestors. Great white sharks can produce up to 100,000 teeth in their lifetimes. For humans, it is closer to a mere 50 and most of those have to last from childhood. Looking back half a billion years, though, the ancestors of sharks and humans had no teeth in their mouths at all, nor jaws. They were armoured fish, sucking in their food. The theory is that either their tooth-like scales began to appear in mouths as teeth, or some of their taste buds became harder. If we knew more about that, and why sharks can regenerate their teeth, then we might learn how humans could grow new teeth in later lives. With Gareth Fraser Assistant Professor in Biology at the University of Florida Zerina Johanson Merit Researcher in the Department of Earth Sciences at the Natural History Museum and Philip Donoghue Professor of Palaeobiology at the University of Bristol Producer: Simon Tillotson

Melvyn Bragg and guests discuss how members of the same species send each other invisible chemical signals to influence the way they behave. Pheromones are used by species across the animal kingdom in a variety of ways, such as laying trails to be followed, to raise the alarm, to scatter from predators, to signal dominance and to enhance attractiveness and, in honey bees, even direct development into queen or worker. The image above is of male and female ladybirds that have clustered together in response to pheromones. With Tristram Wyatt Senior Research Fellow at the Department of Zoology at the University of Oxford Jane Hurst William Prescott Professor of Animal Science at the University of Liverpool and Francis Ratnieks Professor of Apiculture and Head of the Laboratory of Apiculture and Social Insects at the University of Sussex Producer: Simon Tillotson

Melvyn Bragg and guests discuss the remarkable achievement of Aristotle (384-322BC) in the realm of biological investigation, for which he has been called the originator of the scientific study of life. Known mainly as a philosopher and the tutor for Alexander the Great, who reportedly sent him animal specimens from his conquests, Aristotle examined a wide range of life forms while by the Sea of Marmara and then on the island of Lesbos. Some ideas, such as the the spontaneous generation of flies, did not survive later scrutiny, yet his influence was extraordinary and his work was unequalled until the early modern period. The image above is of the egg and embryo of a dogfish, one of the animals Aristotle described accurately as he recorded their development. With Armand Leroi Professor of Evolutionary Development Biology at Imperial College London Myrto Hatzimichali Lecturer in Classics at the University of Cambridge And Sophia Connell Lecturer in Philosophy at Birkbeck, University of London Producer: Simon Tillotson

Melvyn Bragg and guests discuss the ideas and life of one of the greatest mathematicians of the 20th century, Emmy Noether. Noether’s Theorem is regarded as one of the most important mathematical theorems, influencing the evolution of modern physics. Born in 1882 in Bavaria, Noether studied mathematics at a time when women were generally denied the chance to pursue academic careers and, to get round objections, she spent four years lecturing under a male colleague’s name. In the 1930s she faced further objections to her teaching, as she was Jewish, and she left for the USA when the Nazis came to power. Her innovative ideas were to become widely recognised and she is now considered to be one of the founders of modern algebra. With Colva Roney Dougal Professor of Pure Mathematics at the University of St Andrews David Berman Professor in Theoretical Physics at Queen Mary, University of London Elizabeth Mansfield Professor of Mathematics at the University of Kent Producer: Simon Tillotson