Dr Sheila Willis is a forensic scientist who was Director General of Forensic Science Ireland for many years.

She has spent her life using science to help solve cases, working on crime scenes and then analysing material in the lab, and presenting scientific evidence in court.

It’s a complicated business. Forensic science relies on powerful technology, such as DNA analysis, but it cannot be that alone - it’s also about human judgement, logical reasoning and asking the right questions.

It is these fundamentals of forensic science that Sheila has fought for through her long career and what she fears may be becoming lost from the field now.

We find out what happens when the two very different worlds of science and the law clash in the courtroom. How to walk the line of presenting scientific evidence where there is pressure to be definitive where often science cannot be - and what this part of the job has in common with food packaging.

And what makes a good forensic scientist?

We’ll turn the studio at London’s Broadcasting House into a live crime scene to see if host Professor Jim Al-Khalili would be any good as a forensic investigator…

Professor Charles Godfray, Director of the the Oxford Martin School tells Jim Al-Kahlili about the intricate world of population dynamics, and how a healthy obsession with parasitic wasps might help us solve some of humanity's biggest problems, from the fight against Malaria to sustainably feeding a global community of 9 billion people.

So we started farming this bird called chicken, and it spread around the world. But what does it actually TAKE to feed us the amount of chicken we want to consume?

100 years ago this was a scrawny, egg-laying bird, only good for a stew once her eggs ran out – no one ate chicken meat. Fast forward to today and it’s the most consumed protein on the planet. How did we come to eat it in the first place, and what are the consequences of producing chicken meat on the vast, industrial scales we now consume it?

Dr Chris van Tulleken uncovers the extraordinary accident of history that birthed a new industry, and changed the way we eat – and think about – meat forever.

One of the world’s large owls by length, the Great Grey Owl is an enigmatic predator of coniferous forests close to the Arctic tundra. It's most often seen hunting around dawn and dusk, when it perches silently at the edges of clearings. But as Prof Ben Garrod and Dr Jess French delve deep inside to understand its true secret to survival, they find the deep feathery coat belies a deceptively small head and body that‘s evolved unbelievably powerful abilities to silently detect and ambush unsuspecting prey.

Zoologist Ben Garrod and veterinary surgeon Jess French delve deep into some amazing internal anatomy to unravel the secrets to survival of some of nature’s iconic animals.

They begin with one of the rarities of the cat family – the cheetah, which at just under two metres long, is the world’s fastest land animal capable of reaching speeds of up to 70mph in three seconds. As Ben and Jess reveal, the body’s rear muscles, large heart and nostrils enable it to achieve record breaking accelerations. But over long distances, it risks total exhaustion and predation from larger carnivores and the risk of losing its valuable prey. We hear during the course of this intricate dissection, how it treads a fine line between speed and stamina in the quest for survival.

What do you get if you smash two hydrogen nuclei together? Helium and lots of energy – it's nuclear fusion!

Nuclear fusion is the power source of the sun and the stars. Physicists and engineers here on earth are trying to build reactors than can harness fusion power to provide limitless clean energy. But it’s tricky.

Rutherford and Fry are joined by Dr Melanie Windridge, plasma physicist and CEO of Fusion Energy Insights, who explains why the fourth state of matter – plasma – helps get fusion going, and why a Russian doughnut was a key breakthrough on the path to fusion power.

Dr Sharon Ann Holgate, author of Nuclear Fusion: The Race to Build a Mini Sun on Earth, helps our sleuths distinguish the more familiar nuclear fission (famous for powerful bombs) from the cleaner and much less radioactive nuclear fusion.

And plasma physicist Dr Arthur Turrell, describes the astonishing amount of investment and innovation going on to try and get fusion power working at a commercial scale.

Sneezes, wheezes, runny noses and red eyes - this episode is all about allergies.

An allergic reaction is when your immune system reacts to something harmless – like peanuts or pollen – as if it was a parasitic invader. It’s a case of biological mistaken identity.

Professor Judith Holloway from the University of Southampton guides our sleuths through the complex immune pathways that make allergies happen and tells the scary story of when she went into anaphylactic shock from a rogue chocolate bar.

Professor Adam Fox, a paediatric allergist at Evelina Children’s Hospital, helps the Drs distinguish intolerances or sensitivities – substantial swelling from a bee sting, for example - from genuine allergies. Hannah’s orange juice ‘allergy’ is exposed as a probable fraud!

Hannah and Adam explore why allergies are on the increase, and Professor Rick Maizels from the University of Glasgow shares his surprising research using parasitic worms to develop anti-allergy drugs!

Contributors: Professor Judith Holloway, Professor Adam Fox, Professor Rick Maizels

Pi is the ratio between a circle’s diameter and its circumference. Sounds dull – but pi turns out to have astonishing properties and crop up in places you would never expect. For a start, it goes on forever and never repeats, meaning it probably contains your name, date of birth, and the complete works of Shakespeare written in its digits.

Maths comedian Matt Parker stuns Adam with his ‘pie-endulum’ experiment, in which a chicken and mushroom pie is dangled 2.45m to form a pendulum which takes *exactly* 3.14 seconds per swing.

Mathematician Dr Vicky Neale explains how we can be sure that the number pi continues forever and never repeats - despite the fact we can never write down all its digits to check! She also makes the case that aliens would probably measure angles using pi because it’s a fundamental constant of the universe.

Nasa mission director Dr Marc Rayman drops in to explain how pi is used to navigate spacecraft around the solar system. And philosopher of physics Dr Eleanor Knox serves up some philoso-pi, revealing why some thinkers have found pi’s ubiquity so deeply mysterious.

Why are some smells so nasty and others so pleasant? Rutherford and Fry inhale the science of scent in this stinker of an episode.

Our sleuths kick off with a guided tour of the airborne molecules and chemical receptors that power the sense of smell. Armed with a stack of pungent mini-flasks, professor Matthew Cobb from the University of Manchester shows Hannah and Adam just how sensitive olfaction can be, and how our experience of some odours depends on our individual genetic make-up.

Dr Ann-Sophie Barwich from Indiana University reveals how most everyday smells are complex combinations of hundreds of odorants, and how the poo-scented molecule of indole turns up in some extremely surprising places.

With the help of a flavoured jellybean and some nose clips, Hannah experiences how smell is crucial to flavour, adding complexity and detail to the crude dimensions of taste.

Speaking of food, listener Brychan Davies is curious about garlic and asparagus: why do they make us whiff? Professor Barry Smith from the Centre for the Study of the Senses reveals it's down to sulphur-containing compounds, and tells the story of how a cunning scientist managed to figure out the puzzle of asparagus-scented urine.

Finally, another listener Lorena Busto Hurtado wants to know whether a person’s natural odour influences how much we like them. Barry Smith says yes - we may sniff each other out a bit like dogs - and cognitive neuroscientist Dr Rachel Herz points to evidence that bodily bouquet can even influence sexual attraction!

How do winds start and why do they stop? asks Georgina from the Isle of Wight. What's more, listener Chris Elshaw is suprised we get strong winds at all: why doesn't air just move smoothly between areas of high and low pressure? Why do we get sudden gusts and violent storms?

To tackle this breezy mystery, our curious duo don their anoraks and get windy with some weather experts.

Dr Simon Clark, a science Youtuber and author of Firmament, convinces Adam that air flow is really about the physics of fluids, which can all be captured by some nifty maths. The idea of pressure turns out to be key, so Hannah makes her own barometer out of a jar, a balloon and some chopsticks, and explains why a bag of crisps will expand as you walk up a mountain.

Professor Liz Bentley, Chief Executive of the Royal Meteorological Scoiety, reveals how the dynamics of a simple sea breeze – where air over land is heated more than air over water – illustrates the basic forces driving wind of all kinds.

Then everyone gets involved to help Adam understand the tricky Coriolis effect and why the rotation of the Earth makes winds bend and storms spin. And Professor John Turner from the British Antarctic Survey explains why the distinctive features of the coldest continent make its coastline the windiest place on earth.

DO WE HAVE YOUR ATTENTION?

Good! But how does that work!?

Our intrepid science sleuths explore why some things immediately catch your eye - or ear - while others slip by totally unnoticed. Even, on occasion, basketball bouncing gorillas.

Professor Polly Dalton, a psychologist who leads The Attention Lab at Royal Holloway University, shares her surprising research into ‘inattentional blindness’ - when you get so absorbed in a task you can miss striking and unusual things going on right in front of you.

Dr Gemma Briggs from the Open University reveals how this can have dangerous everyday consequences: you are four times more likely to have a crash if you talk on the phone while driving -even handsfree.

Drs Rutherford and Fry also hear from stroke survivor Thomas Canning, who developed the tendency to ignore everything on the left side of space, despite his vision being totally intact.

And Dr Tom Manly, from the University of Cambridge’s Cognition and Brain Sciences Unit, helps our sleuths unpack the neuroscience of this fascinating condition.

Chi Onwurah tells Jim Al-Khalili why she wanted to become a telecoms engineer and why engineering is a caring profession.

As a black, working class woman from a council estate in Newcastle, she was in a minority of one studying engineering at university in London and encountered terrible racism and sexism. She went on to build digital networks all over the world, the networks that make today's instant muli-media communications possible. And Chi built the first mobile phone network in Nigeria, when the country was without a reliable electricity supply. Today she is Shadow Minister for Science, Research and Innovation.

When Chi decided to go into politics, her engineering colleagues were not impressed. Why would anyone leave their noble profession to enter a chaotic, disreputable and dubiously useful non-profession, they asked. But, Chi believes, parliament desperately needs more scientists and engineers, not only to help us solve science-based problems but also to create technical jobs and build a strong economy.

Six and a half million dead. More than a hundred times that infected. The Covid-19 pandemic has wreaked havoc across the globe. But in the final months of the third year of this health crisis, some now claim it’s all over.

Scientists with key roles in the global response join Claudia Hammond to consider the evidence behind the declarations that the pandemic has finished and they set out how, officially, this global health crisis will be brought to an end.

They reject claims that the pandemic is over, but say the emergency phase of this global health crisis is coming to a close.

But only if countries remain vigilant and maintain pandemic preparedness.

If vaccines reach arms, if treatments are shared equally and if nations re-introduce public health measures like mask wearing and social distancing when the inevitable new waves (and potential new variants) emerge, the appalling loss of life we saw at the beginning of the pandemic, they tell Claudia, won’t be repeated.

There are stark warnings too that the dramatic global drop in the sequencing of virus samples (which enables us to see how the virus is evolving) is posing a serious risk.

We can’t react to a new threat, Claudia’s panel say, if you can’t see it. Sequencing, as well as testing, has fallen by 90% since January this year, from 100,000 weekly sequences ten months ago to less than 10,000 now. This severely limits the ability to track the known variants (currently 200 sub-lineages of the Omicron variant).

Produced in collaboration with Wellcome and recorded in front of a live audience in Wellcome’s Reading Room in London, Claudia’s expert panel includes Dr Maria Van Kerkhove, the World Health Organisation’s Technical Lead for Covid-19, Professor Salim Abdool Karim, co-chair of the south African Ministerial Advisory Committee on Covid-19 and a member of the Africa Task Force which oversees the African continent’s response to the virus and Professor Sir Jeremy Farrar, the Director of Wellcome and a former adviser to the UK government on its Covid response.

Presenter: Claudia Hammond Produced by: Fiona Hill and Maria Simons Studio Engineers: Giles Aspen and Emma Harth

Dr Chris van Tulleken is on a mission to find out what we’re eating, why, and who or what might be influencing our decisions. And he’s starting his quest to uncover food truths with the most eaten meat in the world, and one of the most numerous animals on our planet: chicken.

He’s recently been forced to confront a serious gap in his food knowledge - what happens before it gets to our plates - and has decided this, the world’s most popular meat, is an ideal starting point.

Chris’ initial investigations reveal the vast scale of modern chicken consumption; and how a once revered jungle fowl was manipulated to become a modern food success story, a fast-growing heavy-breasted beast to feed the masses.

Now, he's torn: is this a triumph of human ingenuity – or the creation of a monster?

Literature student turned neuroscientist, Prof David Eagleman, tells Jim Al-Khalili about his research on human perception and the wristband he created that enables deaf people to hear through their skin. Everything we see, taste, smell, touch and hear is created by a set of electro-chemical impulses in the dark recesses of our brain. Our brains look for patterns in these signals and attach meaning to them. So in future perhaps we could learn to ‘feel’ fluctuations in the stock market, see in infra-red or echo-locate like bats? Each brain creates its own unique truth and David believes, there are no real limits to what we humans can perceive.

Nobel Prize winning chemist Frances Arnold left home at 15 and went to school ‘only when she felt like it’. She disagreed with her parents about the Vietnam war and drove big yellow taxis in Pittsburgh to pay the rent. Decades later, after several changes of direction (from aerospace engineer to bio-tech pioneer), she invented a radical new approach to engineering enzymes. Rather than try to design industrial enzymes from scratch (which she considered to be an impossible task), Frances decided to let Nature do the work. ‘I breed enzymes like other people breed cats and dogs’ she says.

While some colleagues accused her of intellectual laziness, industry jumped on her ideas and used them in the manufacture of everything from laundry detergents to pharmaceuticals. She talks to Jim Al-Khalili about her journey from taxi driver to Nobel Prize, personal tragedy mid-life and why advising the White House is much harder than doing scientific research.

Who could forget the beginning of 2020, when a ‘mysterious viral pneumonia’ emerged in the Chinese city of Wuhan. Soon, other countries were affected and deaths around the world began to climb. Perhaps most alarmingly of all, there were no proven treatments to help prevent those deaths.

As the World Health Organisation declared the Covid-19 outbreak a pandemic, and the UK and the rest of the world braced itself for what was to come, doctor and drug-trial designer Martin Landray had his mind on a solution, devising the protocol, or blueprint, for the world’s largest drug trial for Covid-19.

As Professor of Medicine and Epidemiology at Oxford University, Martin was perfectly positioned to jump, delivering what became known as the RECOVERY Trial. The trial was tasked to deliver clarity amid the predicted chaos of the pandemic and galvanised every acute NHS hospital in the UK. Within its first one hundred days, it had yielded three major discoveries and it has transformed Covid-19 treatment worldwide, already saving over a million lives. Sir Martin Landray was recently knighted for this work and RECOVERY’s legacy lives on, not just for Covid. Martin plans to revolutionise drug trials for other diseases too.

In the third and final part of our series How Covid Changed Science, Devi Sridhar Professor of Global Health at Edinburgh University looks at the legacy and lessons of the pandemic for scientific research. Tackling the virus became a global issue, but many have pointed out the inequality of both resources and effort in the response. Going forward do we need to be directing research more towards improving health and disease surveillance in less wealthy parts of the world, would investing there help prevent future pandemics?

In the second of our series How Covid Changed Science, Devi Sridhar, Professor of Global Health at Edinburgh University looks at the scientific messaging. Just how do you explain to both politicians and the public that a growing global pandemic is likely to kill many people, and unprecedented measures such as a nationwide lockdown are needed to prevent even more deaths. What information should be imparted and how?

Similarly how to address the clamour for information on the development of vaccines and other potential treatments when there often wasn’t clarity? And with the rise of misinformation how did individual scientists who became the subject of conspiracy theories cope with being targeted?

In this programme we hear from scientists and politicians directly involved with the pandemic response. For some the experience of explaining their often highly technical research to the general public was a daunting experience. For others it became a mission to answer the publics concerns and fears.

Until 2020 developing a new drug took at least 15 years. Scientists by and large competed with each other, were somewhat secretive about their research and only shared their data once publication was secured. And the public and the press had no interest in the various early phases of clinical trials. An incremental scientific step possibly on the road to somewhere was simply not newsworthy. Face masks were the preserves of hypochondriacs in the Far East, with no scientific evidence base for their use.

Now the findings of research are published as soon as they are ready. Often they are being openly discussed in social media before they have been peer reviewed. The speed of research, collaboration between science and industry, and public perception of science are areas that have undergone incredible and likely permanent change.

Devi Sridhar, Professor of Global Health at Edinburgh University hears from scientists in a variety of fields, whose working lives and practices have been affected, in some cases revolutionised by the pandemic.

If you look up into the night sky, there are around 7,000 active satellites orbiting the Earth. They’re part of our daily life – essential for things like the internet, the GPS in our cars and giving us weather reports. Seven thousand might not sound a lot in the infinite expanses of space. But the reality is that most satellites are found in a small slice of the solar system - called Lower Earth Orbit - and countries and satellite companies are planning to launch hundreds of thousands more in the next decade. So things are about to get crowded. In this week’s Discovery, Jane Chambers speaks to scientists, astronomers from the ALMA Observatory in Chile, space environmentalists and satellite companies like SpaceX about the benefits of this explosion in mega satellite constellations, as well as the unintended consequences to those who value a clear and unhindered view of the stars.

Picture: Radio Telescopes at ALMA Observatory in the north of Chile, Credit: Jane Chambers

Giles Yeo learns how to make a Thai green curry with Meera Sodha. This is a recipe without meat or prawns but with tofu and lots of vegetables. If we need to eat less meat and dairy to help prevent global warming- what difference will altering our diets make to our health. For a long time now people have been urged to cut down on red meat and processed foods but if you have been eating them all your life it takes an effort to develop new habits. Plant based products that can replace for example dairy milks, cheeses, sausages, burgers and meat based dishes such as lasagne can be helpful in making this transition but are they healthier?

In Plant Based Promises, Giles Yeo a foodie and academic at Cambridge University, asks how sustainable are commercial plant based products? This is a fast growing sector with a potential value of $162 billion by 2030. Giles travels to the Netherlands Food Valley to look at companies developing plant based alternatives and to find out what role they have to play in changing diets. And Giles designs his own plant based Yeo Deli range online but discovers that new markets are already causing shortages of alternative proteins, so what will the future look like?

In 2019 the Eat Lancet Commission set up specific targets for a healthy diet and sustainable food production. The aim was to keep global warming to within 1.5 degrees and to be able to feed the world’s 10 billion people by 2050. The Commission’s recommendations are best visualised as a plate of food, half fruits, vegetables and nuts and the other half whole grains, beans, legumes and pulses, plant oils and modest amounts of meat and dairy. Is there room on the plate for Giles Yeo Deli Baloney range.

In Plant Based Promises, foodie, researcher and broadcaster Giles Yeo looks at the science behind plant based diets and the increasing number of plant based products appearing in supermarkets and restaurants. The market for plant based products could be worth $162 billion in the next ten years and Giles asks how sustainable and healthy the products are and the role they play in decreasing the world's carbon footprint.

Globally food production accounts for about 30% of greenhouse gases. In the UK we eat over six times the amount of meat and more than twice the amount of dairy products recommended to prevent the global temperature increasing more than 1.5 degrees C, after which extreme weather events become more severe. But eating less meat and dairy means new protein sources from plants are needed and how easy or practical is it for people to change their diets? Veganuary, where people pledge to go vegan for the month of January show that people are willing to change what they eat for a variety of reasons including animal welfare, sustainability and health.

In programme one Giles, an expert on food intake looks at some of the foods being developed to replace animal based foods and looks at alternatives to the iconic cheeseburger. Giles meets biochemist Professor Pat Brown founder of Impossible Burgers, a Silicon Valley start up making burgers from genetically modified yeast to replicate the taste of meat.

But from high tech to the artisanal, sisters Rachel and Charlotte Stevens missed eating cheese so much they are now making cheese alternatives using traditional moulds, cultures and aging techniques while replacing dairy ingredients with nuts.

Dr Julia Ravey and Dr Ella Hubber both have a love of science, but it turns out there’s a lot they don’t know about some of the leading women at the front of the inventing game. In Unstoppable, Dr Julia and Dr Ella tell each other the hidden, world-shaping stories of the engineers, innovators and inventors they wish they’d known about when they were starting out as scientists. This week, the inventor whose incredible capacity to solve problems inspired today’s most popular period products.

Mary Beatrice Davidson Kenner – known as Beatrice – grew up in a family of inventors, creating her first invention at just six years old. And she didn’t stop there – she continued to invent throughout her adult life, including a new and improved sanitary pad in a time when there was still a big taboo around periods.

However, as an African American woman during a time of racial segregation, Beatrice faced injustice and discrimination when trying to get her inventions patented. But if anything, this spurred Beatrice on, and at one point in time she held the most patents of any African American woman.

Dr Julia and Dr Ella are joined by Professor Sharra Vostral and Ashleigh Coren as they tell Beatrice’s remarkable story.

Presenters: Dr Ella Hubber and Dr Julia Ravey Producers: Ella Hubber and Julia Ravey Assistant producer: Sophie Ormiston Production co-ordinator: Elisabeth Tuohy Editor: Holly Squire

The smaller the thing you look at, the bigger the microscope you need to use. That’s why the circular Large Hadron Collider at CERN, where they discovered the Higgs boson is 27 kilometres long, and its detectors tens of metres across. But to dig deeper still into the secrets of the Universe, they’re already talking about another machine 4 times bigger, to be built by the middle of the century. Roland Pease asks if it’s worth it.

Image: CMS Beampipe removal LS2 2019 (Credit: Maximilien Brice/CERN)

Episode 2: Lost in the Dark

Physics is getting a good understanding of atoms, but embarrassingly they’re only a minor part of the Universe. Far more of it is made of something heavy and dark, so-called dark matter. The scientists who discovered the Higgs boson ten years ago thought they’d also create dark matter in the underground atom smasher at CERN. But they haven’t seen it yet. Roland Pease joins them as they redouble their efforts at the upgraded Large Hadron Collider, and travels to Boulby Underground Laboratory inside Britain's deepest mine, where subterranean telescopes hope to see dark matter streaming through the Galaxy.

Image: CMS Beampipe removal LS2 2019 (Credit: Maximilien Brice/CERN)

The machine that discovered the Higgs Boson 10 years ago is about to restart after a massive upgrade, to dig deeper into the heart of matter and the nature of the Universe.

Roland Pease returns to CERN’s 27-kilometre Large Hadron Collider (LHC) dug deeper under the Swiss-French border to meet the scientists wondering why the Universe is the way it is. He hears why the Nobel-prize winning discovery of the “Higgs Particle” remains a cornerstone of the current understanding of the nature of matter; why the search for “dark matter” – 25% of the cosmos - is proving to be so hard; and CERN’s plans for an atom smasher 4 times as big to be running by the middle of the century.

Image: CMS Beampipe removal LS2 2019 (Credit: Maximilien Brice/CERN)

Ant-loving professor, Adam Hart, shares his passion for leaf cutting ants with Jim Al Khalili. Why do they put leaves in piles for other ants to pick up?

Talking at the Hay Festival, Adam describes the experiments he designed to test the intelligence of the hive mind. When does a waggle dance become a tremble dance? And how do the honey bees know when this moment should be?

We like the phrase ‘as busy as a bee’. In fact, bees spend a lot of time doing nothing at all, a sensible strategy from the point of view of natural selection.

And where does Adam stand on insect burgers?

Producer: Anna Buckley

When a person with severe anorexia nervosa refuses food, the very treatment they need to survive, is that refusal carefully considered and rational, as it can appear to those around them? Or is it really the illness that’s causing them to say ‘no’?

This is one of the thorny ethical dilemmas that Jacinta Tan has wrestled with over the course of her career. She is deeply curious about the mind, and has spent hundreds of hours sitting with people with anorexia nervosa, not persuading them to eat, rather listening to them talk about what’s going on in their minds and how the illness influences their decisions.

These rich internal worlds, that she has revealed, shape her work as a Child and Adolescent Psychiatrist at Oxford Health NHS Foundation Trust, where she treats people with eating disorders. The views of those with the condition and their families have been central to the recent government reviews of the Eating Disorder Services that she led in Scotland and Wales.

These conditions can be hugely challenging to treat. Jacinta Tan tells Jim al-Khalili how it's the art of medicine, as much as the science, that helps people recover.

Producer: Beth Eastwood

Pete Smith is very down to earth. Not least because he’s interested in soil and the vital role it plays in helping us to feed the world, mitigate climate change and maintain a rich diversity of species on planet earth. He was born in a pub and failed the 11+ exam (designed to identify bright children just like him) but he became a distinguished professor nonetheless. Tackling climate change in isolation is a mistake, he says. We need to consider all the challenges facing humanity and identify strategies that deliver benefits on all fronts: food security, bio-diversity and human development goals. He tells Jim Al-Khalili about his life and work and the urgent need for our degraded peat bogs to be restored. Peat bogs that have been drained (for grazing or to plant trees) add to our carbon emissions. Healthy peat bogs, however, are carbon sinks. Producer: Anna Buckley

The world is full of colour! But, listener Maya Crocombe wonders ‘how do we see colour and why are some people colour blind?’

Dr Rutherford and professor Fry set out to understand how special light-sensitive cells in our eyes start the process of colour perception, why people sometimes have very different experiences of colour and whether, in the end, colour is really just ‘in our heads’.

Dr Gabriele Jordan from Newcastle University explains why lots of men struggle to discriminate between certain colours and why there were lots of complaints from colour-blind viewers when Wales played Ireland at rugby.

Professor Anya Hurlbert, also from Newcastle University, tackles the most divisive of internet images: The Dress! Did you see it as blue-black or yellow-gold? Anya explains why people see it so differently, and why our ability to compensate for available light is so useful.

To see the Dunstanborough Castle illusion as described in the episode, check out the Gallery on this page and also on the Discovery homepage.

Mathematician Hannah Fry and geneticist Adam Rutherford investigate your everyday science queries. Today, they get stuck into two questions about tides. Lynn Godson wants to know why isn’t high tide at the same time at all points around the coast? Whilst Tim Mosedale asks, could we ever harness tidal power commercially? Did you think tides are caused by the pull of the Moon? And that they come in and out twice a day? Well, yes, that’s true but it turns out there’s so much more to it than that, especially here in the UK, which has the second largest tidal range in the world at the Severn Estuary near Bristol, coming in at an average of 15 metres (50ft in old money). But why should high and low tide times be so different even in places that are relatively close to each other?

The answer partly lies in something called bathymetry (which has more to do with baths than you might think – well basins at any rate). As for harnessing sea power, there are some ambitious projects currently in development and predictions that wave and tidal could make up as much as 15 percent of the UK’s energy needs in future. But how realistic is this and how do you ensure that your power generators can survive the rigours of the ocean – storms, saltwater and all those pesky barnacles?

To help answer these queries, Hannah and Adam are joined by Physicist and Oceanographer, Helen Czerski and Professor Deborah Greaves OBE, who heads up the COAST lab at the University of Plymouth which studies marine renewable energy technologies.

Today The Evidence goes green as Claudia Hammond and her panel of experts discuss plant power, how nature and the natural environment affect our mental health.

Produced in collaboration with Wellcome Collection and recorded in front of a live audience in the Reading Room at Wellcome Collection in London, the programme addresses that widely-held view, even intuition, that plants and nature directly impact on our emotional wellbeing.

As always, Claudia and her panel of experts are interested in the evidence behind such beliefs, and as they reveal, proving this link scientifically, is fiendishly difficult.

The evidence base is growing (especially studies which show being in nature improves your mood) and there is much emerging research which gives tantalising glimpses into exactly which elements in nature could help to produce that green feel-good factor (and which elements can actually make us feel worse).

On stage, a 25 year old semi-professional footballer shares how he first put his hands in the soil after the Grenfell Tower fire in North Kensington in London five years ago, when 72 people lost their lives and left his community traumatised.

Tayshan tells Claudia that nature saved him, and many others, as they planted seeds, re-claimed spaces and built new gardens in the aftermath of the tragedy. All children and young people, he says, should have access to the healing power of nature and he calls on the horticultural establishment to open its doors much wider to enable this to happen.

Beth Collier too, believes that nature should be a meaningful part of everyday life for all. The connection with nature, she says, is fundamental to healing mental distress. A psychotherapist and ethnographer, Beth founded Wild in the City to encourage those who live in urban environments, especially people of colour, to re-connect with nature.

Claudia’s other guests are Kathy Willis, former Director of Science at the Royal Botanic Gardens, Kew, now Professor of Biodiversity at the University of Oxford and author of a soon-to-be-published book called Prescribing Nature and Birgitta Gatersleben, Professor of Environmental Psychology at the University of Surrey and a leading researcher studying the relationship between the natural environment and human wellbeing.

Produced by: Fiona Hill and Maria Simons Studio Engineers: Duncan Hannant and Emma Harth

(Photo: Footpath through a forest Credit: Nik Taylor/UCG/Universal Images Group/Getty Images)

Why does human hair go grey and is it ever possible for it to go white overnight from shock? Hannah and Adam explore why hair goes grey, how much stressful life events and a lack of sleep can speed up the process. They hear from the pilot whose hair turned white after a flight where all 4 of his engines failed after flying through a volcanic ash cloud - was the shock responsible? They also uncover new research which has shown it's possible for greying hair to return to its natural colour and ask if this finding could be exploited to uncover a cosmetic way to reverse hair greying?

In her last year of high school, Olga González-Sanabria went on a field trip to the University of Puerto Rico’s school of engineering – and immediately knew that was what she wanted to do. She followed her passion and after university was recruited by Nasa, where she carried out instrumental work, without which we would not have the International Space Station.

As the very first Latina woman working in engineering at Nasa, Olga’s career has not always been an easy ride, but is filled with remarkable achievements. Dr Ella and Dr Julia tell her story, and Olga herself gives us a first-hand account of her life so far.

Presenters: Dr Ella Hubber and Dr Julia Ravey Producers: Ella Hubber and Julia Ravey Assistant producer: Sophie Ormiston Production co-ordinator: Elisabeth Tuohy Editor: Holly Squire

(Photo: Olga González-Sanabria. Credit: Nasa Glenn Research Center)

Two eyes, two arms, two legs - we are roughly symmetrical on the outside, but inside we are all over the place! We just have one heart, which is usually on the left, one liver on the right, one spleen and one appendix. "Why is that?" wonders listener Joanne.

Our science sleuths discover that being symmetrical down the middle - at least on the outside - is by far the most common body plan across the animal kingdom. Professor Sebastian Shimeld from the University of Oxford takes us on a journey into the deep evolutionary past, to uncover how two-sided body structures first emerged in ancient worm-like creatures, and why this layout eventually proved so useful for swimming, walking and flying.

Garden snails turn out to be a surprising exception – their shells coil in one direction and on just one side of their body. Professor Angus Davison from the University of Nottingham tells the tale of his international quest to find a romantic partner for Jeremy – a rare left-coiling snail who could only mate with another left-coiling snail!

Dr Daniel Grimes from the University of Oregon unfolds the delicate mechanisms by which an initially symmetrical embryo starts to develop differently down one side, and everyone puzzles over the mystery of the left-handed 'mirror molecules' - so called L-amino acids - which turn out to be the building blocks of every living organism. A curious case indeed!

We use wi-fi every day, but do you know how it works? “Is it waves and science or just some mystical magical force?” wonders listener Abby.

Well, our science sleuths are on the case. To help them navigate the strange realm of electromagnetic waves they are joined by Andrew Nix, Professor of Wireless Communication Systems from the University of Bristol. He explains why your wi-fi router won’t heat up your baked beans, but your microwave will.

Andrea Goldsmith, Professor of Electrical and Computer Engineering at Princeton University, also joins to reveal how these waves are crammed full of 0s and 1s- whether that's a pic of your pets or a video chat with pals.

And finally, how do you get the best wi-fi at home? Dr Rutherford, it turns out, has made some rookie errors. Listen out for our top tips so you don't make them too!

‘Why are teens prone to risky behaviour?’ asks Dr Mark Gallaway, ‘especially when with their friends?’ 13 year old Emma wonders why she’s chatty at school but antisocial when she gets home. And exasperated mum Michelle wants to know why her teens struggle to get out of bed in the morning.

Swirling hormones and growing bodies have a lot to answer for but, as Professor of Psychology from the University of Cambridge Sarah-Jayne Blakemore explains, there’s also a profound transformation going on in the brain.

Hannah and Adam discover how the adolescent brain is maturing and rewiring at the cellular level and why evolution might have primed teens to prefer their peers over their parents. Frances Jensen, Professor of Neurology at the University of Pennsylvania, tells us how all these brain changes can impact social relationships. And Dr Rachel Sharman, a sleep researcher from the University of Oxford, reports the surprising findings from her sleep study tracking 100 teenagers around the UK.

Ben Garrod and Jess French get under the skin of Mola mola the world's largest bony fish to unravel this bizarrely shaped predator's ability to swim to a huge range of depths.

Producer Adrian Washbourne

Ben Garrod and Jess French delve deep inside the predatory Burmese Python to examine its extraordinary body plan that enables it to catch, constrict and consume huge prey whole.

Producer Adrian Washbourne

Wild Inside embarks on something we hardly ever witness – a look inside some of nature’s most wondrous animals. Its a rare chance to delve deep into some enigmatic and very different wild animals – from a reptile, to a mammal to a fish – unravelling the intricate internal complexity inside three of the most amazing animals ever to evolve. What makes the ultimate predator? What are the keys to successful survival in an ever-changing environment? Whilst we’ve gained a lot by observing their behaviour from the outside, to truly understand these animals, we need to look at what’s on the inside too.

Ben Garrod, Professor of Evolutionary Biology and Science Engagement at the University of East Anglia, together with friend and expert veterinary surgeon Dr Jess French, open up and investigate what makes each of these animals unique. During each animal post mortem, they’re joined by experts in comparative anatomy, evolution and behaviour as they put these enigmatic animals under the knife. Along the way they reveal some unique adaptations which give each species a leg (or claw) up in surviving in the big wild world.

The series begins with one of the truly exotic loaners of the cat family – which at just over two metres long, covered with beautiful gold and black rosette markings, is pure jungle royalty - the greatest of the South American big cats - the Jaguar

Part 2: One of the largest predatory reptiles - the Burmese Python whose extraordinary singular body plan has enabled nearly 4000 species of snakes to succeed in inhabiting nearly every part of the planet,

Part 3 : The largest bony fish you might never have heard of – the bizarre looking Oceanic Sunfish which is being spotted increasingly in UK waters

Presenters: Prof Ben Garrod, Dr Jess French Producer: Adrian Washbourne

War and conflict turns lives upside down and millions of adults and children witness atrocities, lose loved ones and often lose their homes and even their countries. The psychological and emotional suffering can continue long after the immediate threat to their life has gone. One in every five people touched by war – that’s 20% - will have a mental health problem that needs help and one in twenty or 5% will be severely affected.

As the humanitarian crisis deepens in the Ukraine with millions under bombardment and ten million people forced from their homes, Claudia Hammond and her guests explore the evidence behind the mental health interventions that do take place around the world: do they work and are they reaching the people who need them?

Two Ukrainian psychiatrists tell Claudia about the psychological support they’re trying to coordinate for their traumatised fellow Ukrainians. Dr Iryna Frankova is also a psychologist and she’s chair of the ECNP Traumatic Stress Network and with colleagues she’s helped to launch a new downloadable chatbot which offers information and psychological first aid. Dr Orest Suvalo from the Institute of Mental Health at the Ukrainian Catholic University is in Lviv in the west of Ukraine and he’s been trying to coordinate care for fleeing citizens as they arrive at the city’s railway station.

Claudia’s panel includes Bill Yule, Emeritus Professor of Applied Child Psychiatry at Kings College, London, who pioneered evidence-based interventions for children caught up in war and trauma (he’s one of the founders of the Children and War Foundation set up in the 1990s during the wars in the Balkans); Professor Emily Holmes from the department of psychology at the University of Uppsala in Sweden who uses the power of mental imagery to reduce traumatic, intrusive memories or flashbacks (she’s been using these techniques to develop treatments for refugees who have fled war and conflict) and Dr Peter Ventevogel, psychiatrist and medical anthropologist and senior mental health officer with UNHCR, the refugee agency at the United Nations.

And Dr Kennedy Amone P’Olak, Professor of Psycho-traumatology at the University of Witwatersrand in South Africa joins from Uganda, where he’s tracked the mental health of hundreds of the children and young people who were abducted and recruited by the Lord’s Resistance Army in Northern Uganda.

Produced by: Fiona Hill and Maria Simons Studio Engineers: Phil Lander and Emma Harth

Steve Brusatte analyses the pace of evolutionary change and tries to answer big questions. Why did the dinosaurs die out and the mammals survive? How did dinosaurs evolve into birds? If you met a Velociraptor today you’d probably mistake it for a large flightless bird, says Steve. His intense interest in T. rex, Triceratops and all the other dinosaur species developed when he was a teenager and continues to this day. More recently, however, he’s focussed on the long history of mammals.

For hundreds of millions of years, our mammalian ancestors remained small. Most were mouse-sized. None were bigger than a badger. Steve studies how, when an asteroid collided with earth 66 million years ago, the mammals got lucky. All the big dinosaurs were wiped out and only the small ones with wings survived. (Birds are dinosaurs, by the way). Within half a million years, mammals of all shapes and sizes had taken over on planet earth. Sabre-toothed flesh eaters, cow-sized plant guzzlers and a host of other warm blooded placental animals evolved alongside the badger sized burrowers.

Steve talks to Jim Al-Khalili about his life and work, including the recent discovery of an incredibly well-preserved Pterosaur on the Isle of Skye, a place he likes to call Scotland’s Jurassic Park. Producer: Anna Buckley

Sir Shankar Balasubramanian is responsible for a revolution in medicine. The method he invented for reading, at speed, the unique genetic code that makes each one of us who we are, is ten million times faster than the technology that was used in the human genome project at the turn of the century. What’s more, it can be done much more cheaply than before and on a desktop machine. And it’s transforming healthcare, by helping us to understand the genetic basis of many diseases (particularly cancers) and to develop new diagnostic tests, medicines and personalised treatments. ‘ DNA has never failed to keep me excited and curious’ says Shankar, winner of the highly prestigious 2022 Breakthrough Prize in Life Sciences. He didn’t set out to create a game-changing technology or to make a lot of money. He just wanted to understand the DNA double helix in the greatest possible detail; to reveal how it worked, molecule by molecule. And he still rides a rickety old bicycle to work in Cambridge.

Image ©University of Cambridge

We look at wolves and the programme is a little different, because the predator we’re talking about is very much a predator of our imaginations. Wolves are the spirit of the wilderness, but they also symbolize the darker side of human nature, and many myths and legends surround the wolf from all around the world.

Our fear of the wolf may be primeval, but it is still very much alive and well. The idea that wolves could be reintroduced in Scotland led to headlines about the British Queen's pet corgis being eaten…

So today, as well as hearing about the real animals, we ask why wolves occupy this special place in our imagination, and whether the real and the imaginary overlap with Dr Elizabeth Dearnley, a folklorist and writer based in Edinburgh and Dr Giulia Bombieri from the Museum of Science in Trento, Giulia works with the Life WolfAlps project, tracking and protecting Italian wolves.

Presenter: Adam Hart Producer: Geraldine Fitzgerald

Picture credit: Giulia Bombieri

In a lab in 1950s Kolkata, Asima Chatterjee laboriously extracts chemicals from the Indian snakeroot plant. She knows she will have to send the products away – she does not have the money or resources to analyse them in India. But the tireless and uncompromising chemist perseveres, and her work paved the way for modern-day chemotherapy treatments.

Asima grew up in a time when it was uncommon for women in India to have an education, but went on to become a hugely influential figure in her field whose work is still repurposed and cited today. Dr Ella and Dr Julia take us through her inspirational journey, joined by Prof Sivapriya Kirubakaran and Dr Sarah O’Connor.

Producer/presenter: Dr Ella Hubber and Dr Julia Ravey Assistant producer: Sophie Ormiston Production co-ordinator: Elisabeth Tuohy Editor: Holly Squire

The army ant might be small enough to squash under foot but, make no mistake, it’s a formidable predator. When they club together in their thousands they are a force to be reckoned with. Picture a tiger, comprised of hundreds of thousands of tiny ant-sized units, prowling through the forest and you start to get the idea. They’ll take down anything in their path, from spiders and scorpions to chickens that can’t escape them. There are even grisly stories of African army ants attacking people. But this predator has its uses too - they can be used to stitch wounds and offer a house cleaning service too.

Dr Dino Martins, Executive Director of the Mpala Research Centre in Kenya, and Lecturer at Princeton University, and Daniel Kronauer, Associate Professor studying complex social evolution and behaviour at the Rockefeller University in New York.

Producer: Beth Eastwood Presenter: Professor Adam Hart

Photo credit: Daniel Kronauer

Adam Hart discovers why rattlesnakes make good mothers and how deadly their venom is. There are over 600 different species of venomous snakes around the world with fearsome fangs delivering deadly venoms. Up to a third of the world’s population lives in fear of snakes, but are these reptiles misunderstood? And while Adam living in the UK where there are very few snakes, finds them fascinating, we shouldn’t forget that an estimated 7,400 people every day are bitten by snakes, and somewhere between 220–380 people die as a result. That’s around 2.7 million cases of venomous snake bites, and between 80,000 and 140,000 deaths a year - mostly in poorer communities in the developing world. But with habitat loss and persecution rife, do snakes have more to fear from us than we do from them. Perhaps we should change from Tooth and Claw to to fangs and scales as we dive into the world of snakes with Dr Emily Taylor, Professor of Biological Sciences at California State Polytechnic State University - she’s a specialist in rattlesnakes and their maternal skills and Hiral Naik, the Africa programme manager for Save the Snakes currently studying for a PhD on snake behaviour at University of Witwatersrand

Picture credit: Hiral Naik

Today, Claudia Hammond and her panel of experts focus on what’s been called “the silent pandemic”, the threat to modern medicine of anti-microbial resistance or AMR.

Infections are increasingly resistant to live-saving drugs like antibiotics and many believe the very future of modern medicine is hanging in the balance.

In a series produced in collaboration with Wellcome Collection, this edition of The Evidence is recorded in front of a live audience in the Reading Room at Wellcome in London.

Just last month, a new global study covering 204 countries and territories published in The Lancet reveals the scale of AMR to human health. The number of lives lost is double previous estimates.

The latest data reveals 1.3 million deaths caused directly by resistant infections in just one year, 2019, and five million more deaths were linked with AMR.

The figures are shocking, especially because one in every five deaths were in children, under five years old, with the highest number of deaths in Western Sub-Saharan Africa.

But this is a pandemic that threatens everybody, wherever they live.

Everly Macario a public health researcher from Chicago in the United States shares her family’s story: the death of their 18 month old son, Simon, to a drug-resistant strain of the bacterial infection MRSA (Methicillin-resistant Staphylococcus aureus). The loss of Simon spurred Everly to campaign against the mis-use of antibiotics, particularly in agriculture and farming, which contributes to the rise in AMR.

Leaders in the global fight against AMR join Claudia to discuss the threat to human health and address the paradox that while AMR claims millions of lives, so many die each day because they can’t get access to basic, life-saving drugs like antibiotics.

And Wellcome Collection’s Research Development Lead, Ross Macfarlane, delves into the archives and shares the warning from the inventor of the first antibiotic, penicillin, Alexander Fleming as he accepted his Nobel Prize in 1945, that mis-use would lead to resistance developing.

The new super drug was destined to spawn the new super bug.

Claudia’s guests include the UK Special Envoy on AMR, Professor Dame Sally Davies; the World Health Organisation’s Assistant Director General for Anti-Microbial Resistance, Dr Hanan Balkhy; Senior Research Manager for Drug Resistant Infections at Wellcome, Dr Janet Midega and the Director of ReAct Africa, Dr Mirfin Mpundu.

Produced by: Fiona Hill, Anand Jagatia and Maria Simons Studio Engineers: Duncan Hannant and Emma Harth