CrowdScience

Today, up to 3 billion people around the world play video games, from candy based mobile puzzles to virtual battlegrounds filled with weapons. Many people have turned to gaming during the pandemic as a way of staying connected – but what does science really say about the impact of gaming? Does playing violent video games lead to violence in the real world? Do brain training apps really work? How much gaming is too much – can videogames really be addictive? And how can videogames help us to explore difficult issues like death, grief and loss?Alex Lathbridge and Anand Jagatia look at the evidence and play some games along the way, speaking to psychologists, doctors and game designers about the power of video games to change us - for better or worse.With Adrian Hon, Professor Andrew Przybylski, Professor Pete Etchells, Professor Henrietta Bowden-Jones and Dr Sabine Harrer

Reduce, Reuse, Recycle. It’s a well-known phrase that we all try and follow in our day to day lives. But are our current recycling habits the best they can be? It’s a hot topic at Crowdscience - multiple listeners have contacted Crowdscience with questions about the ins and outs of recycling. We follow one listener’s food waste to a processing plant to investigate whether or not it could be processed in our own homes. But aside from the food waste, what about the containers it comes in? We investigate if food containers really need to be cleaned before we put them in recycling bins, or if that just wastes water.Recycling processes differ all over the world, so we hear from reporter Chhavi Sachdev in Mumbai, India, who follows her plastic waste to find out how plastic sorting and recycling is a whole economy of its own.But new technologies have meant that biodegradable and bioderived plastics are starting to appear in our packaging, and one Crowdscience listener wants to know which is better for the environment – traditional plastic that has been recycled, or bioplastic and compostable alternatives? And looking to the future, could we ever recycle our plastic waste at home and use 3D printers to make useful things out of our own waste?Marnie Chesterton delves into these questions with Circular Economy Project Manager Dr Rhiannon Hunt of Manchester Metropolitan University, to discover the details of recycling and unearth how we can make our own recycling as efficient as possible. With Dave Atkins, reporter Chhavi Sachdev and Dr Rhiannon Hunt. Presented by Marnie Chesterton and Produced by Hannah Fisher for the BBC World Service.[Image credit; Getty Images]

One CrowdScience listener finds herself unconcerned about much of the world’s problems, it leaves her wondering: am I a psychopath?Inspired by a previous episode on empathy, this listener asked is it true that psychopaths don’t empathise and what are the character traits of psychopathy? Marnie Chesterton talks with a diagnosed pro-social psychopath to find out. She also pays a visit to the Netherlands Institute for Neuroscience and gets into an MRI scanner to discover what is happening in her brain when she empathises.Studies suggest around 1 percent of the general population exhibit traits associated with psychopathy and that rises to 3-4 percent in the world of business. But is this really the case?Why is there so much stigma associated with psychopathy and do psychopaths even exist or is it just a convenient term to label those whose emotional range sits outside of the “norm”? Presented by Marnie Chesterton and produced by Caroline Steel for the BBC World Service.Guests: Julia Shaw Jim Fallon Valeria Gazzola Kalliopi Ioumpa[Image credit: Getty Images]

Anyone who has ever taken the Christmas lights out of the cupboard, only to discover they’re hopelessly tangled, will sympathise with this week’s listener Eric. He has a 45m garden hose that always seems to snarl up and snag when he waters his garden, and he wonders what he’s doing wrong? Marnie starts by discovering the important difference between tangles and knots, as she scales a cliff with an experienced climber who explains the way you tie rope is a matter of life and death. Physicists are also fascinated in how string becomes jumbled up and one man has even won an IgNobel award for his work in this field. Doug E Smith discovered that if you put a piece of string in a box then spin it around, its length, thickness and how long you shake the box for, all determine whether it will tie itself up. Not only that, the more the string becomes twisted, the more likely it is to cross over itself and become impossible to untangle.While tangles might be annoying in hair or cables, they’re also a fundamental part of human life. Our DNA is constantly folding itself to fit inside tiny spaces – there are two metres of the stuff inside every cell, where it’s packed down tightly, before it must untangle and duplicate for those cells to divide. It does this with the help of specific enzymes, and when the process goes wrong it leads to cell death. But scientists are also studying molecular tangles that might benefit us humans, and creating nano-sized knots that can be turned into nets or meshes with incredible properties. Producer: Ilan Goodman Presenter: Marnie Chesterton

Standing takes less energy than walking, so why does it feel more tiring? At least, it does for CrowdScience listener Nina. She can march for hours without getting tired, but her legs and feet get achy after just a short time standing still.It’s one of three walking-themed questions CrowdScience is tackling this week. Taking inspiration from our active listeners, Marnie Chesterton walks up a hill with Caroline Williams, author of a new book about why humans are designed to move. We find out how our whole system – body and brain – works better when we’re walking, compared to standing still. We’re probably set up this way because of our evolutionary history: hunting and gathering needed us to be ‘cognitively engaged endurance athletes’.We stop for a break.. but is it true that we shouldn’t sit down to rest during a walk? Our listener Sarah is a keen hillwalker but likes to take the weight off her feet every now and again. Her hillwalking friends disapprove, saying she should rest on her feet. Is this a myth CrowdScience can bust?And finally a question from listener Matteo: is walking or running better for your health? Numerous studies show significant benefits to both forms of exercise, but in the end, the best kind of exercise is the one you’re motivated to do.With Caroline Williams, Dr François-Xavier Li, Professor Dick Greene and Professor Duck-Chul Lee.

Food. For all of us it is a basic necessity and for those lucky enough, it is something we spend a lot of time planning and enjoying. CrowdScience listeners certainly have a lot of food related questions; in this buffet of an episode Marnie Chesterton opens the fridge door to pick the tastiest. Starting with the seemingly simple question of what makes us feel hungry, and ending in outer-space, Marnie investigates flavour, nutrition and digestion. After a year when watching TV has become a core activity for many people stuck in their homes, one listener wants us to find out if eating food whilst watching the TV affects our perception of taste. We then journey to the skies and ask if it is true that food tastes blander on aeroplanes, what does that mean for astronauts’ mealtimes? Back on earth, Marnie explores whether humans are the only animals that season their food.Tuck in your napkins and prepare to feast on a smorgasbord of scientific snacks. Presented by Marnie Chesterton and Produced by Melanie Brown and Hannah Fisher for the BBC World Service. Guests: Professor Charles Spence Dr Kristine Beaulieu Mr. Takashi Funahashi Ruben Meerman Chef Jozef Youseff

It took a while before it was officially recognised as a major symptom of Covid-19, but loss of smell has affected up to 60 percent of people who have had the virus. And for a significant portion, smell continues to be an issue for weeks or months after their recovery. So what’s going on and how can you get your sense of smell back? We tend to think of our sense of smell as something universal – if it smells bad to me, it probably does to you but that is not the case for CrowdScience listener Annabel, who wonders why things other people love to sniff, she finds disgusting. Anand Jagatia investigates the science of smell, gets up close to the world’s smelliest plant and finds out if smell training can help those with long-term issues after Covid. Contributors Ellie Byondin, supervisor of the Princess of Wales Conservatory at London’s Kew Gardens Thomas Hummel, University of Dresden Carl Philpott, from the UK’s Norwich Medical School Sissel Tolaas, artist and smell historian based in Berlin Noam Sobel, Weizmann institute of sciencePresented by Anand Jagatia and Produced by Marijke Peters for the BBC World Service

Scales don’t come planet-sized, so answering a question from David in Ghana may require some ingenuity, after all, calculating the weight of the Earth is a huge task. Using a set of weighing scales and a 400 year-old equation, Marnie Chesterton attempts to find out just how much the Earth weighs and is it getting heavier or lighter over time? But how would a planet gain or lose mass? Which tips the scales: meteorites falling from space or gases constantly escaping from our atmosphere? And does the answer have any implications for the future of Earth? Could the atmosphere eventually run out? Contributors: Anuradha TK, former project director at ISRO Matt Genge, geologist at Imperial College London Jon Larsen, researcher at the University of Oslo Anjali Tripathi, astrophysicist Ethan Seigel, journalist and astrophysicistPresented by Marnie Chesterton. Produced by Caroline Steel for the BBC World Service.[Image: Earth on scales. Credit: Getty Images]

They say life is sweet. Well that’s certainly the case for CrowdScience listener Trevor in Poland who wonders why he can’t stop reaching for the cookie jar. He grew up drinking fruit juice with added sugar but wonders whether his genes could be as important as his environment when it comes to his sweet tooth, especially since his wife seem to be satisfied with mainly savoury snacks. The World Health Organisation says added sugar should constitute a maximum of 5% of our daily energy intake because it can contribute to diabetes, heart disease and obesity. But that’s tricky when you consider it’s now in everything from salad dressings, to savoury sauces.Manufacturers have been promoting sugar alternatives for decades but recreating the unique taste and feel of it in the mouth are a challenge. Marnie Chesterton gets to try a brand new innovation – a so-called ‘rare’ sugar that has 70 percent of the sweetness but almost none of the calories. In nature, allulose is found in figs, but one producer has discovered a way to make it in the lab. Does it taste as good as it claims? Whilst switching to alternative sugars and sweeteners may reduce the calories, some researchers claim that tasting sweetness, wherever it comes from, can disrupt the body’s mechanism for regulating blood-sugar levels, increasing the risk for conditions like diabetes.Presented by Marnie Chesterton and produced by Marijke Peters for the BBC World Service

It's a topic that's taboo in many cultures, yet it's also something nearly every woman experiences – on average upwards of 400 times throughout her life: menstruation. Responding to a flood of questions from our CrowdScience listeners, Marnie Chesterton seeks to unpack how periods affect women physically, mentally and societally. Why did humans evolve to have periods when fewer than two percent of mammals share our experience of menstrual cycles? Is it really a good use of our limited energy reserves? What can the little Egyptian spiny mouse teach us about PMS symptoms? We hear why periods may reduce the number of faulty embryos that implant and how more menstrual cycles may even increase our chances of developing certain types of cancer. Finally, as the number of periods a woman has over the course of her life has more than quadrupled since the pre-industrial era, Marnie asks: Do we really still need to have them? Contributors: Dr Nadia Bellofiore, Hudson Institute of Medical Research at Monash University Dr Deena Emera, Buck Institute Lameck Kiula, Jambo for Development Sally King, Menstrual Matters & King's College London Dr Diana Mansour, New Croft Centre & Newcastle UniversityPresented by Marnie Chesterton Produced by Sam Baker and Melanie Brown for the BBC World Service

As millions more of us move to live in densely populated cities, we almost inevitably face living in closer proximity to our neighbours. Neighbour noise can certainly be a source of annoyance – but could it even be damaging to our health? Increasing evidence suggests that unwanted noise can cause sleep deprivation, distraction and annoyance, as presenter Anand Jagatia finds out. He discovers that noise annoyance has a small but significant impact on our wider health – including our cardiovascular system – but that annoyance is not necessarily down to sound alone. Factors such as perception of the neighbourhood and relationships with our neighbours also play a part. CrowdScience has examined living with unwanted noises before, and we revisit our trip to the acoustics lab at the University of Salford in Manchester, UK. Here, we meet the researchers and engineers investigating the best ways to make our homes more pleasant for our ears whilst still maintaining the ‘buzz’ of city life. Contributors:Contributors: Professor Charlotte Clark, St George’s University of London Professor Trevor Cox, University of Salford Manchester Professor Bill Davies, University of Salford Manchester Dr Mags Adams, University of Central Lancashire (formerly University of Salford Manchester, at time of recording)Produced by Jen Whyntie and presented by Anand Jagatia for the BBC World Service.

You are a star. Literally. You are a carbon-based life form and those atoms of carbon in the molecules that make up your cells were formed by a nuclear fusion reaction at the heart of long dead stars. That goes for the oxygen in your lungs too. And the red blood cells that carry that oxygen to your tissues? They contain haemoglobin, and nestled at the heart of each molecule is an element (iron) formed by a supernova - the fiery explosion at the death of a star. Your body is a walking, thinking museum of some of the most violent events in the universe. This, as CrowdScience host Marnie Chesterton discovers, isn’t as special as it sounds. All of the stuff on the earth - the elements that make clouds and mountains and mobile phones – they all have an origin story. CrowdScience tells that story, starting with the big bang and ending with physicists, creating new elements in the lab. Find out the age of the elements and the distance they have travelled to make their current home on earth. Interviewees: Dr Dorota Grabowska, Professor Andrea Sella, Dr Chris Pearson, Dr Jacklyn Gates (Photo: Neutron star. Credit: Getty Images)

There are over 400,000 species of plant on earth, they’re on every continent including Antarctica. But humans only regularly eat about 200 species globally, with the vast majority of our nutrition coming from just three species. Many of the fruits, leaves and tubers that other plants grow are packed full of toxins that are poisonous to us, and would make us very ill if we ate them. But could we take out the poisons and create new, edible crops? That’s what CrowdScience listener Marija wants to know.Crowdscience dives into this topic, and uncovers the that many crops are poisonous, and why so few plants are eaten globally. Host Anand Jagatia finds that even the modern scientific processes of crop breeding are very slow. But science can now engineer plants at the genetic level by adding, silencing or removing specific genes. This ‘genetic modification’ is hugely controversial but can be highly effective. Anand finds a man who has spent decades making cotton seeds edible by removing the poisons they naturally produce in their seeds. This GM crop could help fend-off starvation. But sometimes introducing poisons can be as important as removing them, as we find in the genetically modified ‘BT eggplants’ in Bangladesh. The new gene makes the vegetable toxic to a major insect pest, so they are much easier to grow. But GM crops are not the perfect solution. They have problems of gene escape, can increase the use of environmentally damaging herbicide, and can be open to monopolisation. In some countries, particularly in Europe, GM crops are hugely controversial. Anand finds out whether these concerns stand up to science and looks at the counterpoint in developing countries in Africa, South Asia and elsewhere, where local farmers like Patience Koku in Nigeria have little time for some of the concerns around GM, particularly as they see poor harvests, poverty and starvation as the more pressing problems. Contributors: Professor Sandra Knapp, The Natural History Museum in London Professor Julie King, Nottingham University Professor Keerti Rathore, Texas A&M University Dr Yousuf Akhond, Bangladesh Agricultural Research Institute Professor Matthew Cobb, University of Manchester Patience Koku, Nigerian Farmer and member of the Global Farmer’s Network Alliance for Science Produced by Rory Galloway and presented by Anand Jagatia for the BBC World Service.Image: Farmer with Fruits. Credit: Arif Hossain, Farming Future Bangladesh.

Have you taken classes to learn a new sport or musical instrument or a language? It’s hard work! Why is it that as children we effortlessly absorb new skills and we don’t as adults? That’s what 50-something listener Gary Grief wondered about playing guitar. Do you need to play more frequently as an adult to attain the same level of expertise? Does the 10,000-hours theory still apply? Presenter and budding tabla-player Anand Jagatia embarks on a musical journey to discover what neuroscience can tell us about muscle memory and learning. Do musicians and sportsmen share the same challenges? By understanding what’s happening in the brain, can we learn how to learn better? With tabla-teacher Satvinder Sehmbey, neuroscientist Dr Jessica Grahn, viola-player Dr Molly Gebrian and sports scientist Prof Yannis Pitsiladis. Presented by Anand Jagatia Produced by Dom Byrne for the BBC World Service[Image: Adult and Child learning Piano. Credit: Getty Images]

When eating a blackberry one day, CrowdScience listener Charles got a tiny seed stuck in his teeth. That got him wondering: why are seeds the size they are? Why does a blackberry have dozens of tiny pips, while a peach has one huge stone right in the middle?Plant seeds have been around for hundreds of millions of years, so they’ve had plenty of time to shapeshift into wildly different forms: from dust-like orchid seeds to giant coconuts. This evolution has been a long and intricate dance with wind, water and animals; we ask how different kinds of seeds might respond to today’s environmental threats and rapidly changing ecosystems.And we go in search of the world’s biggest seed, the coco de mer: native to just two remote islands in the Indian Ocean and weighing up to 18kg, how did this seed evolve to be so much bigger than any other? With Professor Angela Moles, Dr Si-Chong Chen, Marc Jean-Baptiste, Dr Frauke Fleischer-Dogley and Dr Wolfgang Stuppy.Presented by Marnie Chesterton Produced by Cathy Edwards for the BBC World Service[Photo: Different sized fruit seeds. Credit: Getty Images]

Most of us don’t like to dwell on our toilet habits, but this week Crowdscience has gone down the drain to discover what wastewater can tell us about our health.It’s been more than a year since scientists across the globe started to track the spread of Covid-19, with help from home test results and hospital data. Marnie Chesterton investigates the latest tool in their arsenal: sewage. Listener Kevin has heard how human waste can be monitored to check for virus levels, and wants to know if it can also be used to stop the disease in its tracks? Although the coronavirus has been discovered in people’s poo, so far there’s little indication it’s actually being spread through the water system. But by taking regular samples from different parts of cities, authorities are now able to accurately predict a local peak weeks before the population shows signs of sickness, then take immediate measures to alert them. In Detroit we hear how environmental engineer Professor Irene Xagoraraki used this method to detect a rare strain of Herpes which doctors didn’t even know was a potential problem. Marnie also talks to Professor Nick Thomson from the Wellcome Sanger Institute, who sequenced the genome of the bacteria that causes cholera, to understand how it has crisscrossed the globe. He discovered that the pandemic currently devastating Yemen actually originated in Asia. It’s a discovery that has changed how the WHO is thinking about this killer disease and could have important implications for vaccination programmes. But our effluent can also pose environmental problems, and Professor Andrew Johnson from the UK’s Centre for Ecology and Hydrology explains there are now as many as 300,000 chemicals that could threaten natural habitats. While authorities try to test each one individually, he’s concerned they may have different effects when they mix in wastewater, and current monitoring systems don’t take this into account. Not only that, but some of these substances contain silver nanoparticles, which Professor Juliane Filser tells us stick around in soil for ever, threatening organisms and bacteria at the base of the food chain. Presented by Marnie Chesterton and Produced by Marijke Peters for the BBC World Service.[Image: Sewage outlets. Credit: Getty Images]

Grief is universal. It is something almost all of us will go through at some point. And it is something that the people we love will experience when we die.Grief can be all consuming, it can make everyday tasks like getting out of bed, feel impossible. Which makes listener Oliver from Australia wonder - what is the point? It doesn’t bring what we lost, back.Why have we evolved to be so affected by loss? Be it the death of a loved one, the end of a relationship or the loss of a job. Does it serve any purpose? Or perhaps it is just the price we pay for being a social species with such strong connections.Image: Families Mourn Victims of The Tamaulipas Massacre in Tuilelén, Guatemala Photo by Josue Decavele/Getty ImagesProduced by Caroline Steel and presented by Marnie Chesterton for BBC World Service.

Gossip often has negative connotations, but does it get a bad rap? Might it serve a useful function and should we think of gossiping as an advanced social skill rather than a personality defect? CrowdScience listener Jayogi thinks it might be useful, and has asked CrowdScience to dig into the reasons why we find it so hard to resist salacious stories.Presenter Datshiane Navanayagam meets a scientist who views gossip as a key evolutionary adaption - as humans started to live in bigger cooperative groups, gossiping was a way of bonding and establishing acceptable group behaviour as well as cementing reputations of trustworthiness.Datshiane heads to the local park to catch some real gossiping in action and finds out that whilst people like to gossip they don’t consider themselves gossipers. Datshi asks a team of scientists what information we are most keen to share and glean in these interactions and if there is such a thing as ‘good’ and ‘bad’ gossip. She hears that in some group settings – like in the workplace - gossip can enhance cooperation and limit free-riders, but that it can also have a more self-serving dark side. Datshiane finds out if our stone-age gossipy minds are fit to operate in the world of mass communication and social media – is our fixation on celebrities related to our being hard wired to gossip?Presenter: Datshiane Navanayagam Producer: Melanie Brown[Image: Gossiping people. Credit: Getty Images]

If a tree falls in a forest, and no-one is there to hear it, does it make a sound? This is an age-old debate that listener Richard and his family have been arguing about for years. Can CrowdScience settle it once and for all? Caroline Steel speaks to experts in hearing, biology, philosophy, physics and sound design, which takes her to some unexpected places.Professor Stefan Bleek is an expert in psychoacoustics who says that sounds only exist in our heads. Dr Eleanor Knox and Dr Bryan Roberts are philosophers that make her question if anything exists outside our own perception. Professor Lilach Hadany wonders if it’s limited to humans and animals - could other plants hear the falling tree too? And Mat Eric Hart is a sound designer who says that sound is subjective – it’s always tangled up with our own interpretations.Things get truly weird as we delve into the strange implications of quantum physics. If there is such a thing as reality, doesn’t it change when we’re there to observe it? Does the tree even fall if we aren’t there?Presenter: Caroline Steel Producer: Anand Jagatia(Image: Fallen Tree. Credit: Getty Images)

Animals experience all the colds, stomach pains, headaches, parasites, and general illnesses that humans do. But unlike us, animals can’t just grab a painkiller off the shelf at the supermarket to cure it. They don’t have a pharmacy to browse… or at least, not the sort that we’d recognise. Listener Andrew Chen got in touch to ask whether animals use any kind of medicine themselves. After all, our own drugs largely come from the plants and minerals found in wild habitats. So perhaps animals themselves are using medicines they find in nature. Presenter Anand Jagatia speaks with the primate researcher who stumbled across a chimp chewing on a bitter leaf 35 years ago, Professor Mike Huffman, whose observations opened up a whole new field of research. We discover why plants contain the medicinal compounds they do, and how butterflies with brains no bigger than a pin-head are still able to select and use medicine to protect their young. We think of medicine as a human invention - but it turns out that we’ve learnt a lot of what we know from copying the birds, bugs and beasts.Presented by Anand Jagatia Produced by Rory Galloway Image: Chimp eating. Credit: Getty Images

The space industry, with its fuel-burning rockets, requirements for mined metals and inevitable production of space junk, is not currently renowned for its environmental credentials. Can space exploration ever be truly environmentally friendly? Presenter Marnie Chesterton answers a selection of listeners’ questions on the topic of space environmentalism. She starts by examining the carbon footprint of spaceship manufacturing here on Earth, and asking whether reusable rocket ships such as Space X or Virgin Galactic offer a green route for commuting or tourism in low Earth orbit. Just beyond our atmosphere, space junk and space debris are multiplying at an exponential rate, jeopardising our communications and mapping satellites, and even putting our access to the wider solar system at risk. As more probes and landers head to the Moon and Mars, what plans are in place to deal with space debris far beyond Earth? Presented by Marnie Chesterton Produced by Jen Whyntie for the BBC World Service[Image: Space Junk. Credit: Getty Images]

This week CrowdScience investigates the information superhighway connecting mind with body. The Vagus nerve is part of our parasympathetic nervous system, delivering information from all our major organs to the brain stem, and stimulating it can help us switch off our fight or flight response and calm us down. But listener Mags wants to know what science says about its impact on our general wellbeing? Marnie Chesterton learns some deep breathing techniques and discovers how the length of our exhale is closely linked to our heart rate, all of which is important for developing something called vagal tone. Cold water immersion also said to stimulate the Vagus, so Marnie braves a freezing shower, only to discover she needs to get her face wet but keep the rest of her body dry, to avoid what scientists called autonomic conflict, which is when your stress response and calming response are both switched on by the same event. Activating both arms of the nervous system in this way can lead to serious heart problems in some people. New research into the gut-brain axis has shown that the Vagus nerve may be responsible for transporting the so-called happy hormone serotonin, which could have important implications for the treatment of depression. And innovations in electrical stimulation of this nerve means implanted devices may soon be used to treat inflammatory conditions like arthritis. Presented by Marnie Chesterton and produced by Marijke Peters for the BBC World Service Contributors: Dr Lucy Kaufmann, Adjunct Professor of Neurology, NYUMike Tipton, Professor of Human and Applied Physiology, University of Porstmouth Mark Genovese, Emeritus Professor of Medicine, Stanford University Dr Karen-Anne McVey Neufeld, Brain Body Institute, McMaster University[Image credit: Getty Images)

The sudden agony of stubbing a toe or burning a finger can make even the most polite among us swear our heads off. It’s like a reflex, a quick-release valve for the shock. But why do expletives give us such a sense of relief? Why does it sometimes feel so good to swear?We set out to explore the science of swearing, prompted by a question from our listener Gadi. Psychological studies have shown bad language can relieve pain, or even make us stronger; we test out these theories for ourselves, and try to figure out why certain words are charged with such physical power.We don’t just use strong words in shock or anger, either. They can help us to bond with others, to express joy, solidarity, or creativity. And although people curse all over the world, it’s not quite the same everywhere. We hear what people like to swear about in different countries, and whether swearing in a second language can ever be quite so satisfying.Presented by Anand Jagatia Produced by Cathy Edwards for the BBC World Service(Photo: Woman swearing. Credit: Getty Images)

Listener Paula from Kenya is a computer scientist, she can’t help but notice the inequality in her workplace. With only 1 in 10 countries having female heads of state, there is no doubt that men are in charge. Paula wants to know if there is any scientific underpinning to this inequality? Perhaps it can be explained by our brains and bodies? Or does evolution weigh in? Or maybe it is all down to society and the way we raise our boys and girls. The toys and ideals we give our children must surely have an impact. And most importantly, if we want a world run by men and women equally, how can we get there? We hear how Iceland became the most gender equal country in the world. Presented by Marnie Chesterton. Produced by Caroline Steel for the BBC World Service[Image: Men in board room. Credit: Getty Images]

It’s the stuff of fairy tales – a beautiful cottage, with windows, chimney and floorboards … and supported by a living growing tree. CrowdScience listener Jack wants to know why living houses aren’t a common sight when they could contribute to leafier cities with cleaner air. The UK has an impressive collection of treehouses, but they remain in the realm of novelty, for good reasons. Architects are used to materials like concrete and steel changing over time, but a house built around a living tree needs another level of flexibility in its design. That doesn’t mean it’s impossible and CrowdScience hears about a project in the Ethiopian capital Addis Ababa, where architect Ahadu Abaineh made a three-storey, supported by 4 living Eucalyptus trees as a natural foundation.Host Marnie Chesterton meets some of the global treehouse building fraternity, including builder of over 200 structures, Takashi Kobayashi, who adapts his houses to the Japanese weather. In Oregon, USA, Michael Garnier has built an entire village of treehouses for his “Treesort”. He’s developed better ways of building , including the Tree Attachment Bolt, which holds the weight of the house while minimising damage to the tree.Professor Mitchell Joachim from Terreform One explains the wild potential of living architecture, a movement which looks at organic ways of building. He’s currently building a prototype living house, by shaping willow saplings onto a scaffold that will become a home, built of live trees.Photo Credit: Ahadu Abaineh

Do you find your bearings quickly or are you easily disorientated? Do your friends trust you with the directions in a new city? Finding our way in the physical world – whether that’s around a building or a city - is an important everyday capability, one that has been integral to human survival. This week CrowdScience listeners want to know whether some people are ‘naturally’ better at navigating, so presenter Marnie Chesterton sets her compass and journeys into the human brain. Accompanied by psychologists and neuroscientists Marnie learns how humans perceive their environment, recall routes and orientate themselves in unfamiliar spaces. We ask are some navigational strategies better than others?Marnie also hears that the country you live in might be a good predictor of your navigation skills and how growing up in the countryside may give you an wayfaring advantage. But is our navigational ability down to biology or experience, and can we improve it? With much of our modern map use being delegated to smartphones, Marnie explores what implications an over-reliance on GPS technology might have for our brain health.Presenter: Marnie Chesterton Producer: Melanie Brown(Photo:Lost man with map. Credit: Getty Images)

Could being happier help us fight infectious disease?As the world embarks on a mass vaccination programme to protect populations from Covid-19, Crowdscience asks whether our mood has any impact on our immune systems. In other words, could being happier help us fight infectious diseases? Marnie Chesterton explores how our mental wellbeing can impact our physical health and hears that stress and anxiety make it harder for our natural defence systems to kick in – a field known as psychoneuroimmunology. Professor Kavita Vedhara from the University of Nottingham explains flu jabs are less successful in patients with chronic stress. So scientists are coming up with non-pharmacological ways to improve vaccine efficiency. We investigate the idea that watching a short feel-good video before receiving the inoculation could lead to increased production of antibodies to a virus. And talk to Professor Richard Davidson who says mindfulness reduces stress and makes vaccines more effective.[Image: Happy couple wearing masks. Credit: Getty Images]

When planning to have a baby, women are expected to give up everything from smoking to alcohol, even soft cheese. But the other half of fertility comes from the sperm, usually provided by a man. So should men also give up their vices to improve the quality of their sperm, and their chances of conception? That’s what Listener Stuart in Australia wants to know. He emailed CrowdScience after he and his wife had been trying to have a second child for two years. He gave up alcohol, and coffee, but wants to know if there is any hard science to back up the idea that this would improve his fertility. To find out, presenter Anand Jagatia speaks with Professor Allan Pacey, a scientist who specialises in the study of male fertility and sperm. He discovers that male subfertility accounts for 50% the problems with getting pregnant. And we’re far from alone. Sperm is a remarkably diverse, but also fragile cell. Across the animal kingdom, different species have problems with male fertility, but have adapted novel ways to improve their chances of reaching the egg. Men often struggle to speak about their fertility, and reporter Chhavi Sachdev tells Anand the impact this has on couples in India who struggle to conceive, or don’t want to. She speaks with fertility specialist Professor Nirmal Kumar Lohiya about how this reticence to speak about fertility is changing. Viruses from Mumps to HIV have long been known to target the delicate sperm production cells in the testicles. Dr Krutika Kuppalli tells Anand why, and what we know about the possible impact of SARS CoV-2 on male fertility.Professor Allan Pacey gives Anand and Stuart some advice for what to do while trying to conceive - don’t wear tight underwear - and get used to talking about your swimmers or even getting them checked out. Contributors: Professor Allan Pacey - Andrologist at the University of Sheffield in the UK. Dr Nicolla Hemmings, expert on bird sperm, Royal Society Dorothy Hodgkin Research Fellow at the University of Sheffield, UK. Professor Nirmal Kumar Lohiya, Fertility specialist and co-developer of RISUG male contraceptive, University of Rajasthan, India Dr Krutika Kuppalli, Assistant Professor at the Medical University of South Carolina, USA Chhavi Sachdev, Reporter and presenter for CrowdSciencePresented by Anand Jagatia, Produced by Rory Galloway(Image: Sperm cells Credit: Getty images)

Covid-19 has prompted a cleaning frenzy. CrowdScience listener William works as a personal trainer in a gym, and while cleaning’s always been part of his job, it’s now taken over much of his working day. He’s constantly wiping down equipment and doing regular deep cleans, and he reckons he can sanitize his hands 40 times in one shift.This kind of routine might strike a chord with many of us, and it’s certainly vital to take hygiene seriously during times of pandemic.But could there be any downsides to all this extra cleaning? There’s a whole world of microbes out there: some, like SARS-CoV-2, make us sick, but others are essential for our health. A rich microbiome is linked to a healthy immune system, while ‘good’ microbes help keep ‘bad’ ones at bay. And what about the chemicals in cleaning products – do they have any unintended consequences for our health?CrowdScience turns to the experts to ask whether our supercharged hygiene routines could damage our immune systems, or promote the spread of superbugs. And we hear why, as long as we have a good diet, plenty of fresh air, and ideally a furry pet, we don’t need to worry too much about being too clean. Presented by Marnie Chesterton Produced by Cathy Edwards for the BBC World Service(Photo credit: Getty Images)

When it comes to speed, humans have got nothing on cheetahs - or greyhounds, kangaroos or zebras for that matter. It’s over long distances we really come into our own: when running for hours or even days, our body structure and excellent sweating skills make us able to outpace much faster mammals.But what are the limits of human endurance? Can we run ever further and faster, and what’s the best diet to fuel such ambitions?This week’s questions come from two CrowdScience listeners in Japan who already know a fair bit about stamina, having run several marathons and long-distance triathlons between them. We head to Greece, legendary birthplace of the marathon, to witness an even more arduous challenge: hundreds of athletes following in the footsteps of the ancient Greek messenger Pheidippides, to run an astonishing 246km across the country. The ever-so-slightly less fit CrowdScience team do our best to keep up, and try to discover the secrets of these runners’ incredible endurance.Presenter: Marnie Chesterton Producer: Cathy Edwards(Photo: a runner in the Spartathlon ultramarathon, with kind permission from the International Spartathlon Association)

One of the more surprising consequences of the pandemic has been the trend for people wanting to move out of cities and back to the countryside. Not everyone has that privilege of course, but undoubtedly for some living in urban areas during lockdown, the lack of access to green spaces took its toll on their mental health and physical well-being. Now, with renewed hope of a global vaccine roll-out, ensuring more people have better access to nature is more important than ever, especially in cities of glass, steel and concrete. Italian CrowdScience listener Enrica loves nothing better than walking along the verdant riverbank near her home after a hard week at work. But is this activity doing more than making her feel good? Is it having an actual effect on her health? Presenter Anand Jagatia meets Enrica and visits a radical scheme in the city of Milan, where officials have been working hard to increase urban green features and have committed to planting 3 million trees and building twenty new parks by 2030.One such idea is the innovative Bosco Verticale - or vertical forest, planted up the side of two high rises apartment blocks. Amongst other benefits It’s hoped it could provide cooling microclimates to reduce the dangers of summer heat, and improve resident’s mental health.Produced by Jennifer Whyntie. First broadcast October 2019.(Photo: Tree lined "tunnel" in the English countryside of West Sussex. Credit: Getty Images)

As regular listeners may recall, CrowdScience has delved into the strange world of fungi before, as we dug down into the forest floor to reveal how plants and trees are connected to the vast mycelial network known as the “wood wide web”. But what makes this network possible and how might it have evolved? Fungi are incredibly clever, or at least , it appears that they’re capable of displaying complex behaviour that gives them the appearance of intelligence. In this episode, we speak to fungal ecologist and author of a new book, Merlin Sheldrake, about fungal “brains”, the evolution of magic mushrooms and zombie insects – the astonishing way certain fungi can take over the bodies of ants and wasps in order to sow their spores above ground.Presented by Anand Jagatia Produced by Rami Tzabar for the BBC World Service.Image: Getty Images

At Christmas, is there a better gift than knowledge? CrowdScience has cooked up its own version of 'secret Santa', with members of the team setting one another the challenge of answering surprising questions from all over the world. Are humans the only animals to exercise? Can you get colder than absolute zero? Why are sounds louder at night? When it comes to food dropped on the floor, is there such thing as the "three second rule"? And, does honey really have healing properties? Producers and presenters from the CrowdScience team speak to all manner of experts, from zoologists through to material scientists, to find the answers. Presenter: Marnie Chesterton Producer: Caroline Steel

CrowdScience listener Simon has a problem. He’s always bumping into things, dropping tools and knocking stuff over. And he’s sick of it. He wants to know what is going on. Was he born like this? Or is it contagious? And most importantly, can he do anything about it, or is he going to be the proverbial ‘bull in a china shop’ for the rest of his life?Host Anand Jagatia gets on the case, investigating the complex coordination needed for the simplest movements, like throwing a ball and catching it. With help from Dr Andrew Green, an exercise physiologist from Johannesburg University, he delves into our secret “sixth sense”, proprioception, which helps us locate our limbs without looking. Anand discovers that an easy task, like kicking a football, needs multiple parts of the brain to coordinate in order to work smoothly. Assistant Professor Jessica Bernard from Texas AMU studies the brain, particularly the cerebellum, a part that controls smooth movements. Dr Bernard explains how tiny glitches and larger lesions in different parts of the brain can make us clumsy in different ways. And how we use our thinking powers to stay balanced; a reason why, as your memory goes with old age, you’re more prone to falling over.Our listener is not alone. Around the world, there is an under- diagnosed condition that affects millions of us. Developmental Coordination Disorder (DCD), also known as dyspraxia is a motor coordination condition that affects 5% of the global population. As Professor Amanda Kirby from the University of South Wales and CEO of Do-It solutions explains, if you can’t tie shoelaces, catch a ball and your handwriting is awful, there’s a chance that you have DCD. There’s a large genetic component, so you are likely to come from a clumsy family.There’s no cure for DCD/Dyspraxia but all of us are capable of becoming better at a chosen task, and there’s a common pathway to mastery, whether that’s bike mechanics or open heart surgery. Professor Roger Kneebone is the author of Becoming Expert, and he talks to Simon about possible solutions to clumsiness, including accepting and living with it. [Image: Man slipping on banana. Credit: Getty Images]

The space between stars is usually measured in light years, but this makes it less easy to acknowledge the true scale of the distance. Even the closest star system to Earth, Proxima Centauri, is 4.2 light years or 40.13 trillion kilometres from Earth. If we are ever going to bridge the gap between the stars, we will have to have some very fast spaceships, with extremely reliable, long-lasting technology on board. So does science allow for these spacecraft to exist? That’s what listener Allan wants to know, and to find out, Presenter Anand Jagatia speaks with Tracy Drain, a systems engineer at NASA JPL responsible for overseeing the development and missions of multiple unmanned interplanetary probes including some around Jupiter and Mars. She tells us the challenges involved with simply keeping our spacecraft working for the long-haul.Even if we can overcome issues of wear and tear over time, powering a ship to other star systems will not be easy. Today’s chemical rockets are too inefficient for the job, so we speak with Rachel Moloney, a researcher in electric propulsion to ask if this relatively new technology could power ships through interstellar space. Faster than light travel is the solution most often found in Science Fiction, but it goes against Einstein’s laws of relativity. Is there a way around it? Theoretical physicist Professor Miguel Alcubierre thinks there may be, and he describes the way a spaceship may be able to create a bubble of spacetime around itself to move faster than light without breaking these fixed laws. But there’s a catch... Contributors: Tracy Drain – Systems Engineer - NASA Jet Propulsion Lab, California, USA Rachel Moloney – Researcher in Electrical Propulsion - Surrey Space Centre, UK Professor Samuel Tisherman – Surgeon – University of Maryland school of Medicine, USA Dr John Bradford – President & CTO of SpaceWorks, USA Professor Miguel Alcubierre – Theoretical physicist known for the ‘Alcubierre Warp Drive’ – National University of Mexico Presented by Anand Jagatia Produced by Rory Galloway [Image: Speceship. Credit: Getty Images]

From dumping raw sewage into rivers to littering the streets with our trash, humans don’t have a great track record when it comes to dealing with our waste. It’s something that CrowdScience listener and civil engineer Marc has noticed: he wonders if humans are particularly prone to messing up our surroundings, while other species are instinctively more hygienic and well-organised.Are we, by nature, really less clean and tidy than other animals? Farming and technology have allowed us to live more densely and generate more rubbish - maybe our cleaning instincts just aren’t up to the vast quantities of waste we spew out? CrowdScience digs into the past to see if early human rubbish heaps can turn up any answers. We follow a sewer down to the River Thames to hear about The Great Stink of Victorian London; turn to ants for housekeeping inspiration; and find out how to raise hygiene standards by tapping into our feelings of disgust and our desire to follow rules.Presented by Marnie Chesterton and produced by Cathy Edwards for the BBC World Service.[Image: Man on beach with rubbish. Credit: Getty Images]

This year, dramatic wildfires wreaked havoc across the globe from Australia to Siberia. CrowdScience listener Melissa wants to know the extent to which climate change is a factor in blazes that appear to be increasing in both frequency and intensity.Presenter Anand Jagatia hears how scientists use alternative worlds in computer models, to understand the role that global warming plays. After Siberia’s hottest ever year on record, he discovers the impact of increasing temperatures on boreal forests – and how they could help release huge stocks of carbon that has been stored in the soil. But is there anything we can do to prevent this happening? He visits the UK’s Peak District region, where conservationists are re-wilding a massive area with a special species of moss, which may offer a solution to an increase in infernos.Presented by Anand Jagatia and Produced by Melanie Brown for the BBC World Service. [Image: Forest Fire. Credit: Getty Images]

Every year, Western Afghanistan is hit with a fierce 120-day wind, and listener Hamid wants to know what causes this phenomenon? He’s from the city of Herat, where what starts as a gentle breeze in the morning can pick up to become a dangerous gale just a few hours later, devastating buildings and causing power outages. The BBC’s Abdullah Elham in Kabul tells us the country has plenty of other ‘friendly’ wind but this one is considered ‘fierce’. CrowdScience talks to Professor Amir Aghakouchak to discover more about the phenomenon, and learns about the pollution problems Herat’s summer storm causes in neighbouring Iran. But it’s not all bad news. Professor Lorraine Remer explains how NASA used satellites to map how wind transport Saharan sand almost half way round the world, fertilising the Amazon rainforest. Presented by Marnie Chesterton and produced by Marijke Peters for the BBC World Service[Photo: Tree in wind in desert. Credit: Getty Images]

We all feel pain on a regular basis; when we stub a toe, break a bone or even experience heartbreak. Bebeto from Cameroon wants to know how to cope with a pain in his wrist that just won’t go away. Does a positive mindset help? Or perhaps meditation? Marnie Chesterton speaks to psychologists and neuroscientists to find the answers. We hear from two people with very different experiences of pain. Lucy has fibromyalgia and experiences pain all over her body every day. While Stephen has a rare genetic condition which means he doesn’t feel physical pain at all. But they both argue that pain shouldn’t always be unwanted. Perhaps we need to embrace and accept our pain in order to beat it. Presented by Marnie Chesterton. Produced by Caroline Steel for the BBC World Service[Image: Man in pain. Credit: Getty Images]

CrowdScience listeners come in all shapes, sizes and ages. This episode is dedicated to our younger listeners who, as we’ve learned before, are experts at asking those superficially obvious questions that for parents, are anything but easy to answer. To start off with, Sylvia, asks why elephants are so big? As we hear from our expert – mammals were at one time, much larger – so perhaps the question should be, why aren’t they bigger? We investigate what drives body size in the animal kingdom.Presenter Marnie Chesterton, together with our ‘cub’ reporter Arlo, goes in search of the most brilliant scientific minds to respond to a slew of other queries. Shambhavi, from Singapore wonders why humans have five digits on each hand? And Benni from California asks why dogs don’t get sick when they drink from muddy puddles? Do dogs have some amazing ability to fight off viruses and bugs?Beyond the confines of our planet, we’ve also got a question from Olivia, from Sydney, Australia, who regularly contemplates the universe: what is the biggest object in it she wonders? Marnie and her experts do their best to solve these mysteries.Presented by Marnie Chesterton, produced by Dom Byrne for the BBC World Service. Image: Getty Images

We’ve probably all got a friend who sings along wildly out of tune - or maybe you are that person. But why are some of us apparently tone deaf, while others can hold a melody? Can you train yourself to sing in tune, or is it mostly down to raw talent?These musical questions, from CrowdScience listeners Jenny and Anastasia, certainly struck a chord with us. Anastasia loves to sing but her friends tell her she’s off-key - or that “a bear trod on her ear,” as they say in her native Russia. Is it possible for her to improve her singing voice, and what are the best ways of going about it?Both musicians and scientists help us tackle these questions, and explain what’s going on in our ears, brains and throats when we try to sing the right notes. We learn about congenital amusia, a condition which makes it almost impossible to tell if you’re in tune or not, and attempt to tease out the relative influence of our genes and our environment when it comes to musical ability.Presented by Marijke Peters and produced by Cathy Edwards for the BBC World Service.Image: Child Singing. Credit: Getty Images

All living things are related to each other, from elephants to algae, e-coli to humans like us. Within our cells we hold genetic information in the form of DNA or RNA. But despite viruses sharing these molecules, many scientists don't consider them to be 'life'. Viruses cannot reproduce on their own, but some can insert their DNA into a host to pass genes sideways through the branching tree of life. As a result, viruses’ relationship with life is.... complex. Two of our listeners had viruses on the mind, so they sent in the same question to CrowdScience. Senan from Singapore and Melvin from South Africa want to know how viruses began to see if this can tell us whether they shared a common ancestor with humans. To dig into this complexity Marnie Chesterton speaks with an expert on Koala genetics – Dr Rachael Tarlinton. Koalas are in the middle of tackling a retroviruses, a type of virus that plants DNA into our cells as a reproduction strategy. Her research could reveal why humans life has so much viral DNA within our genomes. Marnie speaks with a computational biologist Professor Gustavo Caetano-Anolles, who has found a new way to trace the family tree for billions of years using proteins common to all life on earth, and speaks with Professor Chantal Abergel who paints a picture of how viruses went from being the losers of evolution, to being highly successful parasites of cells. If you have a question for CrowdScience, please email: [email protected] by Rory Galloway Presented by Marnie Chesterton Contributors: Dr Chelsey Spriggs - Postdoctoral fellow at the University of Michigan in the USA Dr Rachael Tarlinton - Associate Professor at the University of Nottingham in the UK Professor Gustavo Caetano-Anolles - The University of Illinois in Urbana Champagne, USA Professor Chantal Abergel - Aix Marseille Université in France Graeme Dick - Head Keeper, Longleat Zoo and Safari Park, UK

Curious CrowdScience listeners have suddenly been struck by the oddity of their behaviours. Elise ponders why she blushes. Thankfully, listener David is a vascular surgeon and knows a thing or two about blushing, as he performs operations on people debilitated by constant red-dening. He has some answers for us, but asks why did blushing evolve?In the past, red cheeks have been linked to necrophilia, repressed cannibalism, and even a de-sire for men to experience menstruation! Thankfully, research has come a long way since then, as blushing experts Peter de Jong and Corine Dijk explain. Scientists believe that it evolved as a nonverbal signal to show someone you’re sorry or that you care about what they think. This would have important for our survival in the group, en-suring we didn’t get into a fight or get kicked out the group. Anand Jagatia gets to grips with blushing and other bodily behaviours – including a question from Thai listener Nitcha who wonders why we yawn as well as a question from Mohamed in Ghana and Biana in Trinidad and Tobago who both asked why people scratch their heads when they think. To answer these questions, Anand’s joined by yawning researcher Andrew Gallup and Sophie Scott as well as body language expert Blanca Cobb. Produced by Graihagh Jackson for the BBC World Service.

Crowdscience solves a range of listeners’ cosmic mysteries, from the reason we only ever see one side of the moon, to why planets spin, and discover the answer can be found in the formation of the solar system. We talk to astronomer Dr Carolin Crawford to understand how stars are made, and investigate the art of astronomy with journalist Jo Marchant, hearing how the ancient Greeks came up with a zodiac long before the invention of a telescope, revealing an intimate relationship between humans and the night sky.Presenter: Marnie Chesterton Producer: Marijke Peters [Image: The Solar System. Credit: Getty Images]

Why am I embarrassed to be naked? Chumbuzzo in Zambia wonders. And what would happen if we ditched our clothes and embraced nudity? Presenter Anand Jagatia and Producer Caroline Steel spend the day naked with other naturists to see if they can shift their embarrassment. Maybe there are good evolutionary reasons to cover up or perhaps we are contributing to inequality and negative body image by hiding our real selves? Marnie Chesterton explores different cultural attitudes to nudity and finds out about the science behind embarrassment. Clothes optional. Presented by Marnie Chesterton. Produced by Caroline Steel for the BBC World Service

Many of us willingly subject ourselves to pain and irritation by eating chilli. CrowdScience listener Tina wonders what’s driving this apparent masochism: why does ‘feeling the burn’ make so many of us feel so good?It’s just one of several tasty questions we tuck into in this episode. Also on the menu is stew: why does it taste better the next day? Listener Helen’s local delicacy is Welsh cawl, a meat and vegetable concoction. Tradition dictates it should be eaten the day after it’s made, but is there any science behind this?And we finish the meal with cheese. Listener Leander asks what makes some cheeses blue, some hard and crumbly, and some run all over your fridge. How is milk transformed into such radically different end products?Presented by Marnie Chesterton and Alex Lathbridge Produced by Cathy Edwards, Marnie Chesterton and Alex Lathbridge for the BBC World Service.[Photo:Woman eating red Chilli Pepper. Credit: Getty Images]

What does science say about controlling urination, and other bodily functions? We tackle three queries about peeing triggers, pooing positions and missing sweat. This episode CrowdScience presenter Marnie Chesterton poses some of the best listener follow-up questions that have landed in our inbox to a panel of experts.Listener Samuel in Ghana is wondering why watery sounds seem to induce urination. Producer Melanie Brown heads out to survey whether this is the case for individuals in an actual crowd at a public fountain in London. And urologist and trustee of the International Continence Society Marcus Drake talks Marnie through how he uses the sound of running water during his work as a hospital doctor helping patients with common but distressing peeing issues, and the limitations of research into this question.And he’s not the only listener who wants us to dig deeper into topics we’ve explored on the show before. Anna in Tokyo also got in touch after hearing our show about toilets, to ask if there is a toilet design that is most ‘natural’ for our health. Gastroenterologist Anton Emmanuel explains why small changes in people’s posture whilst pooing can have a significant impact on their quality of life.Finally, listeners Stelle, James and Joel emailed [email protected] after hearing Marnie investigate hyperhidrosis: Sweating too much. They and their relatives experience the opposite:

If you’re one of the millions of people who used lockdown to try something new like baking sourdough bread, you may well be wondering what’s happening chemically inside your loaf, especially if the end result keeps changing. Well, you’re not alone. Listeners Soheil and Sean are both keen bakers but want to know more about the thing that makes bread rise: yeast. What is yeast? Where does it come from and can you catch it? And how hard is it to ‘make’ yourself? Soon after lockdown took effect, commercial supplies of the stuff disappeared from supermarket shelves across the globe. The shortage also affected brewers the world over. A big fan of yeast in most of its forms, Marnie Chesterton took on the challenge of creating her own. She talks to the brewers who hunt rare strains to create the perfect beer, and hears from the biologist who says these amazing microbes, used for thousands of years, could be used to make food production more sustainable. And she discovers how this simple ingredient could be instrumental in the fight against climate change. Presented by Marnie Chesterton and Produced by Marijke Peters for the BBC World Service.

Squelching into the science of slime, Chhavi Sachdev seeks to find out why it took so long for listener Helen Tyson to remove slime from her fingers, after she picked up a tiny slug while gardening. This unfortunate and hugely repulsive experience set Helen to wonder what it is about the structure of slug slime that makes it gloopy, so she sent Chhavi to meet with slug slime expert Professor Andrew Smith who reveals how the complex molecular structure of this pervasive fluid makes it so difficult to scrub off.Slime is used by all sorts of creatures including the Giant African Land snail, which invaded India by hitching a ride on imported timber. But invasive species biologist Dr TV Sajeev reveals that these snails are themselves giving a lift to another meningitis-causing parasite that can infect people. Chhavi looks for these massive molluscs in her own garden in Mumbai. Marine biologist Helen Scales describes how animals can use slime for catching food, mating, defence, or even transportation, and Chhavi speaks with Dr Adam Celiz who has been inspired by this slimy adaptability to create a tool that can provide new cells to replace damaged heart cells after a cardiac arrest. Slugs, snails and even fish keep a variety of useful chemicals in their slime. Some make them taste bitter, and others numb the mouth of predators, but they may also prevent the animals from contracting infections. Dr Sarah Pitt has investigated these compounds in the slimy mucus of a garden snail and discovered an antibiotic that is brand new to science. Slime is pretty disgusting, but it’s also completely fascinating. Presented by Chhavi Sachdev Produced by Rory Galloway (Photo: Slugs Mating. Credit: Getty Images)

Anyone else had their flight cancelled? The COVID 19 pandemic has had a huge impact on air travel – air traffic in 2020 is expected to be down 50 per cent on last year. But beyond the obvious disruption to business and people’s lives, how might the quieter skies affect our weather and climate? One curious listener, Jeroen Wijnands, who lives next to Schiphol airport in the Netherlands, noticed how there were fewer clouds and barely any rainfall since the flights dropped off. Could airplanes affect our local weather? Also, did we learn anything from another occasion when airplanes were grounded, during the post-9/11 shutdown? How will the current period impact our future climate? Marnie Chesterton investigates this question and discovers some of the surprising effects that grounded aircraft are having: on cloud formation, forecasting and climate change. Presenter: Marnie Chesterton, Producer: Dom Byrne[Photo:Commercial airplane parking at the airport. Credit: Getty Images]