In the previous episode the team started investigating the following enquiry, sent in to [email protected]:

They considered cockatoos, chimpanzees and Hannah's dog, Molly, to discover that humans are unique, with just one in ten of us being left-handed.

Today, they look inside the left-handed brain. Some researchers point to a link between left-handedness and impairments like autism or dyslexia. Others claim that lefties are more creative and artistic.

So what's the truth? The team consults Professors Sophie Scott, Chris McManus and Dorothy Bishop to find out.

Presenter: Adam Rutherford & Hannah Fry

Neal Shepperson asks, "What determines left or right handedness and why are us lefties in the minority?"

When we started investigating this question it became clear that there were just too many scientific mysteries to squeeze into one episode. So there are two whole episodes devoted to this very Curious Case.

One in ten people are left-handed, but where does this ratio come from and when did it appear in our evolutionary past?

Hannah talks to primatologist Prof Linda Marchant from Miami University about Neanderthal teeth and termite fishing.

Adam consults handedness expert Prof Chris McManus from University College London. He's been trying to track down the genes responsible for whether we're right or left handed.

If you have any Curious Cases for the team to investigate please email [email protected]

Presenter: Adam Rutherford & Hannah Fry

"Can horses count?" asks retired primary school teacher, Lesley Marr.

Our scientific sleuths consider the case of Clever Hans, with a spectacular re-enactment of a 20th century spectacle. Plus, we hear from Dr Claudia Uller who has been conducting modern studies on equine counting.

Mathematician Prof Marcus Du Sautoy explains the basic concept of counting to Adam, and Hannah looks across the animal kingdom to find the cleverest mathematical creature.

If you have any questions you'd like the duo to investigate, please email [email protected]

Presenters: Hannah Fry, Adam Rutherford

Our science detectives answer the following perplexing problem, sent in by Hannah Monteith from Edinburgh in Scotland:

"How does leg hair know it has been cut? It doesn't seem to grow continuously but if you shave it, it somehow knows to grow back."

Hannah consults dermatologist Dr Susan Holmes, from the Hair Clinic at Southern General Hospital in Glasgow, to discover why the hairs on your legs don't grow as long as the hairs on your head.

Adam attempts to have a serious discussion about the evolutionary purpose of pubic hair with anatomist and broadcaster Prof Alice Roberts.

If you have a scientific mystery for the team to investigate, please email: [email protected]

Presenters: Hannah Fry, Adam Rutherford

Today the team study the heavens, thanks to listener Brian Passineau who wonders 'why everything in space tends to be circular or spherical?'

Hannah gazes at Jupiter at The Royal Observatory, Greenwich with Public Astronomer, Dr Marek Kukula.

Science writer, Philip Ball, explains how the astronomical obsession with celestial spheres came to an untidy end.

And physicist Dr Helen Czerski helps Adam on his quest to find the perfect natural sphere.

If you have a scientific mystery for the team to investigate, please email: [email protected]

Presenters: Hannah Fry, Adam Rutherford

Listener Edith Calman challenges our scientific sleuths to investigate the following conundrum:

'What is it about extreme pain, emotional shock or the sight of a three year old stumbling their way through an off-key rendition of 'Away in a Manger' that makes the brain send messages to the lacrimal glands to chuck out water?"

Hannah discovers how the eye produces tears, with the help of Dr Nick Knight.

Broadcaster Claudia Hammond, author of 'Emotional Rollercoaster', explains why Darwin experimented on his children until they cried.

Adam watches a tearjerker to take part in a psychological study, but ends up getting quite angry instead.

If you have any everyday mysteries you'd like the team to solve email: [email protected]

Presenters: Hannah Fry, Adam Rutherford

Today the team examine the chemistry of tea, in answer to the following question sent in by Fred Rickaby from North Carolina:

"When we are preparing a cup of tea and the cup contains nothing but hot, brewed tea we need to add milk and sugar. My wife always adds the sugar first, stirs the cup to make sure it is dissolved and then add the milk. So, is that an optimum strategy for adding milk and sugar to a cup of tea?”

Adam consults Prof Andrea Sella from University College London about the perfect formula for a cup of tea. Inside his tea factory in Kent, Master Blender Alex Probyn teaches Hannah an unusual method for tasting tea.

Most importantly, the duo discovers whether you should add milk first or last. But can tea professionals really tell the difference?

If you have any questions for Drs Rutherford & Fry to investigate send them to [email protected]

Presenters: Hannah Fry, Adam Rutherford

An unusual case today for science sleuths Hannah Fry and Adam Rutherford sent by Elisabeth Hill:

'Can we shoot garbage into the sun?'

The duo embark on an astronomical thought experiment to see how much it would cost to throw Hannah's daily rubbish into our stellar dustbin. From space elevators to solar sails, they explore the various options that could be used to send litter to the Sun.

Featuring space scientist Lucie Green and astrophysicist Andrew Pontzen.

If you have any everyday mysteries for the team to investigate using the power of science, please email: [email protected]

Presenters: Hannah Fry & Adam Rutherford

Science sleuths Hannah Fry and Adam Rutherford investigate the following question sent in by Philip Le Riche:

'Why do some people faint at the sight of blood, or a hypodermic needle, or even if they bash their funny bone? Does it serve any useful evolutionary purpose, or is just some kind of cerebral error condition?'

Adam is strapped onto a hospital tilt table in an attempt to make him blackout and Hannah receives an aromatic surprise.

Featuring consultant cardiologists Dr Nicholas Gall and Dr Adam Fitzpatrick and cardiac physiologist Shelley Dougherty.

If you have any scientific cases for the team to investigate please email: [email protected]

Presenters: Hannah Fry & Adam Rutherford

Drs Rutherford and Fry tackle a vexing case sent in by Daniel Sarano from New Jersey, who asks why people shout on their mobile phones in public.

Our science sleuths find the answer by delving into the inner workings of telephony with a tale of engineering rivalry, Victorian etiquette and early otolaryngology.

Featuring acoustic technologist Nick Zakarov and historian Greg Jenner, author of 'A Million Years in a Day: A Curious History of Daily Life.'

If you have any scientific cases for the team to investigate please email: [email protected]

Presenters: Hannah Fry & Adam Rutherford