Curious Cases Folgen

"Do we know what causes déjà vu?" asks Floyd Kitchen from Queenstown in New Zealand. Drs Rutherford and Fry investigate this familiar feeling by speaking to world-leading reseacher Chris Moulin from the University of Grenoble in France and memory expert Catherine Loveday from Westminster University. Plus, they find out why early investigations classed déjà vu as a type of paranormal phenomenon.For most of us, it's a fleetingly strange experience, but for some people it can become a serious problem. Lisa from Hulme in Manchester started experiencing déjà vu when she was 22 with episodes that could last all day. The origin of her déjà vu has been the key to helping psychologists investigate its cause.Presenters: Hannah Fry, Adam Rutherford Producer: Michelle Martin.

"What happens to the human voice as we age? If I hear a voice on the radio, I can guess roughly how old they are. But singer's voices seem to stay relatively unchanged as they age. Why is this?" All these questions were sent to curiouscases@bbc.co.uk by Jonathan Crain from Long Island in New York.The Doctors discover how the human voice is produced and listen to how our voice sounds when it emerges from our vocal cords. Acoustic engineer Trevor Cox, author of 'Now You're Talking', explains why German and French babies have a different accent. And neuroscientist Sophie Scott describes what happens when boys' voices break, and why a similar thing can happen to women during the menopause.Finally, our voices often change dramatically in later life, as demonstrated by impressionist Duncan Wisbey from Radio 4's Dead Ringers. Expect cameos from David Attenborough, Dumbledore and Paul McCartney.Presenters: Hannah Fry, Adam Rutherford Producer: Michelle Martin.

"What is the fifth dimension?" asks Lena Komaier-Peeters from East Sussex.Proving the existence of extra dimensions, beyond our 3D universe, is one of the most exciting and controversial areas in modern physics. Hannah and Adam head to CERN, the scientific cathedral for quantum weirdness, to try and find them.Theoretical physicist Rakhi Mahbubani explains why we think that dimensions beyond our own might exist. Adam meets Sam Harper, who has spent 14 years hunting for an elusive particle called the 'graviton', which could provide a portal to these extra dimensions. But if they exist, where have these extra dimensions been hiding? Sean Carroll from Caltech explains various ideas that have been dreamt up by physicists, from minuscule hidden planes to gigantic parallel worlds.Producer: Michelle Martin Presenters: Hannah Fry, Adam Rutherford.