"Could you make a machine to make it rain in minutes?" asks listener Alexander from Hampshire, aged 12. For this series, with lockdown learning in mind, Drs Rutherford and Fry are investigating scientific mysteries for students of all ages. Rutherford and Fry dive into the clouded story of weather modification.

And then for the technology itself. Mark Miodownik, scientist and author of Liquid: The Delightful and Dangerous Substances The Flow Through Our Lives, reveals that a technique called cloud seeding has almost certainly been tried in different places around the world for decades. But, whilst it’s supposed to induce showers and even clear the way for sunny spells, the results aren’t always reliable. And even if we can make it rain, Liz explains why messing with the weather may be at our peril.

First broadcast on BBC Radio 4 in 2020.

"Why do our tummies rumble - and when they do, does it always mean we are hungry?" asks listener James, aged 12. For this series, with lockdown learning in mind, Drs Rutherford and Fry are investigating scientific mysteries for students of all ages. To get to the bottom of this noisy problem, the doctors tune in to our guts.

Geneticist Giles Yeo studies food intake and obesity. He explains the wavy workings of our digestive system, and how those audible rumbles are a sign that digestion is taking place – a phenomenon thought to be onomatopoeically named 'borborygmi' by the ancient Greeks, and explored further in the gruesome 19th century experiments of surgeon William Beaumont.

However, tuning in to the gut’s sounds can tell us more than whether we need a snack. Family doctor Margaret McCartney takes us through the process of how and why she and her medical colleagues may use a stethoscope to listen to your abdomen for both particular noises and silence.

Microbiologist Barry Marshall has taken medical listening one step further in his Noisy Guts Project. Inspired by microphones used to listen for termites hiding in walls, the Nobel Prize-winning scientist is trialling an acoustic belt, which could be worn to help diagnose and treat Irritable Bowel Syndrome.

Presenters: Hannah Fry, Adam Rutherford

First broadcast on BBC Radio 4 in 2020.

Rutherford & Fry are back with longer duration episodes brought to you from slightly shouty socially distanced studio and bedroom settings.

"What are wormholes and do they really exist?" asks Manlee-Fidel Spence, aged 12. In this exotic episode, the doctors investigate how wormholes would work.

Cosmologist Andrew Pontzen explains why wormholes could allow you to travel through time as well as space. And physicist Jim AlKhalili outlines the infinite problems this could generate.

When it comes to wormholes and time travel, many science fiction stories have married solid science and successful storytelling, as Jennifer Oullette describes, but others really have defied the laws of physics. Jim also reveals why some quantum physicists now think that wormholes could be everywhere. But don't expect to jump back to 1955 any time soon.

Presenters: Hannah Fry, Adam Rutherford

First broadcast on BBC Radio 4 in 2020.

Two cold callers feature in this episode. Jennifer Langston from Ontario in Canada sent this message to [email protected]:

"My husband has just taken up cold water swimming and he'll swim in temperatures as low as 6 degrees Celsius. I worry that it's too cold for him, but he claims that 'swimming in cold water is good for you', which drives me bonkers. Can you tell us if there is any scientific proof behind this?”

Adam takes a trip to his local lido and asks the locals why they get a kick out of a chilly winter dip. Meanwhile, Hannah calls the Antarctic to talk to meteorologist Richard Warren about the perils of a frozen beard.

Our second cold caller, Sarah Dudley, asks why women get cold feet in bed. Thermal physiologist Heather Massey is on hand with the answer.

But when it comes to the natural world, other animals are masters of sub-zero living. Frozen Planet producer Kathryn Jeffs, from the BBC's Natural History Unit, explains why polar bears are perfectly designed for the Arctic. And we discover why Paddington Bear is better suited to Peru.

Presenters: Hannah Fry, Adam Rutherford

First broadcast on BBC Radio 4 in 2020.

“I suppose a cold is called a cold because we catch it in the winter," writes Alison Evans from St Albans. "But why is it that we get more colds in winter than in the summer?”

This week's Cold Case is all about the common cold, a set of symptoms caused by hundreds of different strains of cold and flu viruses.

Adam uncovers the stinky history of infectious disease with medical historian Claire Jones.

Virologists Jonathan Ball and Wendy Barclay describe how spiky viruses lock on to our cells, but why many of the symptoms of a common cold are due to our own body's overreaction.

Plus, we delve into the science of sneezing with nose doctor Carl Philpott.

Presenters: Adam Rutherford, Hannah Fry

"My question is about something I became aware of at a young age," explains Samantha Richter from Cambridgeshire.

"I was sitting on the carpet at school, being read a story by the teacher. My hair felt as though it was standing on end as waves of a tingly sensation washed over my head. I subsequently found certain scenes in films had this effect, when actors were talking softly, or someone was having their hair brushed."

"Then, a few years ago, I discovered that there is a name for the tingles, it's called ASMR. My question is, what is ASMR, and why do we experience it?"

In this episode, we explore the world of Autonomous Sensory Meridian Response. It's a trend which has risen quickly on YouTube, with devoted subscribers following their favourite 'ASMRtists' whose videos receive millions of plays.

Hannah speaks to Dr Nick Davis, who published the very first research paper on the phenomenon in 2015. And Adam is put to the test by Dr Giulia Poerio, to see if he is susceptible to the sensation of ASMR. Are there any proven benefits for devoted fans, or is it just a YouTube fad?

We've concocted our very own Curious recordings so you can find out if your brain begins to tingle. You'll find them in our normal podstream, where you can enjoy Adam and Hannah crafting a very ASMRy cocktail for your listening pleasure.

Presenters: Hannah Fry, Adam Rutherford

First broadcast on BBC Radio 4 in 2020.

Adam Rutherford concocts an Old Fashioned. First listen to our episode on ASMR, then grab some headphones and let Adam mix you a cocktail.

Hannah Fry mixes a mojito. This ASMR recording accompanies the episode of The Curious Cases of Rutherford and Fry on the science of ASMR.

Two questions about love and heartbreak in this episode for our Valentine's special edition.

Jessica Glasco, aged 29, wrote in to ask about the power of love and how it affects our brain.

Hannah tracks down Dr Helen Fisher, who conducted some of the first MRI studies on love by putting besotted couples into the brain scanner.

Adam talks to broadcaster Claudia Hammond, author of Emotional Rollercoaster, to find out how psychologists have grappled with the messy business of love. And we hear why a small furry vole was thought to hold the answer to the mystery of monogamy.

Our second question concerns the pain of heartbreak - why does our heart ache? Can emotional hurt cause physical pain? On call is our very own agony aunt, Irene Tracey, Prof of Pain Research.

Presenters: Hannah Fry, Adam Rutherford

First broadcast on BBC Radio 4 in 2020.