Everyone has fears – but what makes a fear become a phobia? Why are some people scared of spiders (arachnophobia), buttons (koumpounophobia), or the colour yellow (xanthophobia)? Or why are others are scared of situations, like small spaces (claustrophobia), empty rooms (kenophobia) or heights (acrophobia)?

This is a question which has been bothering Crowdscience listener Scott, who has a phobia of bridges. He gets anxious and panicky when driving over bridges and is scared he’ll lose control of the car. It’s also a question that struck a chord with presenter Caroline Steel. She is claustrophobic, particularly in lifts, steering clear of them at all costs and even once climbing nine flights of stairs in crutches to avoid using the lift.

But where do these phobias come from and why do some people have them and not others? To investigate, Caroline speaks to experts to discover where phobias come from, why we have them and how they develop. And she visits a psychologist to learn about different types of treatment for phobias, and to receive treatment herself in the hope that one day, maybe she’ll be able to take the lift instead of the stairs.

Contributors:

Professor Paul Salkovskis, Director, Oxford Centre for Psychological Health, UK

Presenter: Caroline Steel

(Image: Person sitting on high up bridge. Credit: ljubaphoto / Getty Images)

CrowdScience listener Leo gets stressed when his young children start screaming at the same time in the middle of the night. He wants to know why we haven’t evolved to deal with the stress more effectively. The challenges of bringing up a family are nothing new and we don’t face the same dangers as our ancestors, so why do we still react as if it’s a life-threatening emergency? Caroline Steel finds out what stress is for, what it does to us and whether we have in fact evolved to manage it.

Contributors:

Tashfia Ahmed, biomedical engineer, post-doctoral researcher, City University, London

Presenter: Caroline Steel

(Image: Frustrated father holds baby in his arms. Credit: Jamie Grill / Getty Images)

Many of us are worried about the environment, but the aim of living in a truly sustainable way is hard to pin down. Do we all need to stop buying things? Is it down to governments to make the changes for us? Is there somewhere in the world painting a picture of the end goal?

It’s a question that has bothered CrowdScience listener Cate for 20 years! She’s worried we’re not doing enough for the environment and just wants a clear scenario of what it might look like to live sustainably, in a way that could work for all eight billion of us on the planet.

It’s a big question, so this week presenter Caroline Steel has teamed up with her friend and colleague Graihagh Jackson from The Climate Question podcast to answer it.

They head to the remote Danish island of Bornholm in the Baltic Sea, which is aiming to go carbon neutral by 2025 and zero waste by 2032. How are they going about it and could this be replicated elsewhere? We visit a ground-breaking project turning nappies into compost, meet a glassblower making tableware out of wasted insulin vials, and find out how pig waste can power homes.

This edition of CrowdScience hones in on Bornholm’s zero waste goal. Will the island make it?

Listen to The Climate Question’s look at the island’s quest to go carbon neutral here: BBC World Service - The Climate Question, Going carbon neutral - lessons from Denmark - www.bbc.co.uk/programmes/w3ct5bkg (Available from 3rd September)

Presenters: Caroline Steel and Graihagh Jackson

(Image: Dr David Christensen, Project Manager at BOFA, Bornholm’s waste authority with presenter Caroline Steel in front of a giant mound of waste bound for the island’s incinerator. The incinerator will be shut down in 2032 when the island aims to be zero waste. Credit: Sophie Eastaugh)

For hundreds of millions of years insects controlled the skies. Before birds, bats and pterodactyls, insects were the only creatures that had evolved the ability to fly: a miracle of physics and physiology requiring their bodies to act in coordinated ballet.

This week three separate CrowdScience listeners have been asking questions about the flight of butterflies and moths. How do they move so erratically, yet land so precisely? What makes such tiny insects such accurate flyers?

Presenter Anand Jagatia -- not the biggest fan of either butterflies or moths -- visits Butterfly Paradise at London Zoo to meet keeper Mark Tansley. Anand tries to get over his aversion by immersing himself in fluttering creatures.

He then meets insect flight expert Sanjay Sane to learn the hidden mechanics behind their aeronautical skills: the vortexes of air generated by their wings and the complex muscle architecture inside their torsos. Next, aerospace engineer Amy Lang explains how the scales on their wings reduce air resistance by clever manipulation of the air and how this function trades off against other uses of the scales: for colour, for keeping dry, and much more.

All of these abilities are put to the test during the incredible global migrations that some butterflies undertake. Gerard Talavera tells Anand how he turned previous thinking about butterfly migration across Africa on its head.

Presenter: Anand Jagatia

(Photo: Crowdscience presenter Anand Jagatia crouches next to a butterfly. Credit: Phil Sansom)

How do you think about the internet? What does the word conjuror up? Maybe a cloud? Or the flashing router in the corner of your front room? Or this magic power that connects over 5 billion people on all the continents of this planet? Most of us don’t think of it at all, beyond whether we can connect our phones to it.

CrowdScience listener Simon has been thinking and wants to know how much it weighs. Which means trying to work out what counts as the internet. If it is purely the electrons that form those tikitok videos and cat memes, then you might be surprised to hear that you could lift of the internet with 1 finger. But presenters Caroline Steel and Marnie Chesterton argue that there might be more, which sends them on a journey.

They meet Andrew Blum, the author of the book Tubes – Behind the Scenes at the Internet, about his journey to trace the physical internet. And enlist vital help from cable-loving analyst Lane Burdette at Telegeography, who maps the internet.

To find those cables under the oceans, they travel to Porthcurno, once an uninhabited valley in rural Cornwall, now home to the Museum of Global Communications thanks to its status as a hub in the modern map of worldwide communications. With the museum’s Susan Heritage-Tilley, they compare original telegraph cables and modern fibre optics.

The team also head to a remote Canadian post office, so correspondent Meral Jamal can intercept folk picking up their satellite internet receivers, and ask to weigh them. A seemingly innocuous question becomes the quest for everything that connects us, and its weight!

Producer: Marnie Chesterton

(Image: Scales with data worlds and symbols interspersed throughout. Credit: Getty Images)

Dogs have been our best animal buddy for thousands of years. They’ve helped us out in countless ways from hunting alongside us to guiding us as service dogs. Talk to any pet owner and they’ll tell you how much joy their dog brings them. But you’ll also probably hear about vets bills, muddy footprints, or chewed up slippers. There are plenty of claims about the ways in which dogs might benefit our physical and mental health -- but how strong is the evidence?

This week on CrowdScience, listeners Jason and Finn in Guernsey want to know if there’s any real evidence that our furry friends can benefit our health and wellbeing.

Join Anand Jagatia as he enlists the help of his own pup, Stella, to explore the evidence. He uncovers the profound effects that service dogs can have on the mental health of military veterans in the US. Anand ponders the strangely unique relationship between humans and dogs and we learn about the surprising ways that about growing up with a pet dog can impact your health.

Presenter: Anand Jagatia

Contributors:

(Photo: Jack Russell leaping into the air trying to catch a ball. Credit: Brighton Dog Photography/Getty Images)

Imagine spending six months of every year living in total shade. That’s what life is like for residents of the Norwegian town of Rjukan, set so low in a valley that they see no direct sunshine at all from October to March.

Marnie Chesterton heads there to hear about an ingenious solution: giant mirrors that beam rays down into the town square, where locals gather to feel the reflected heat.

The man behind the project was motivated by a need for winter sun – but how much difference does it really make to our health and happiness? That’s the question posed by this week’s CrowdScience listener Michael, who has noticed living in the rainy Australian city of Melbourne is taking its toll.

Many pensioners claim sunshine relieves achiness as well as conditions like arthritis but one of the biggest scientific studies found temperature has no real impact on reported pain levels, while factors like air pressure and humidity may play a role.

When it comes to our mood, it seems that spending time outside is more important than feeling the heat. The optimum temperature for wellbeing is around a cool 19 degrees centigrade, while excessive warm weather has been linked to an increase in violence and crime.

You can watch a visualisation of this episode on YouTube: Is the 'sunshine cure' a real thing? - CrowdScience, BBC World Service podcast - YouTube

Producer: Marijke Peters

Contributors:

Dr Anna Beukenhorst, University of Manchester

(Photo: Young woman enjoying sunset. Credit: Muriel De Seze/Getty Images)

Imagine spending six months of every year living in total shade. That’s what life is like for residents of the Norwegian town of Rjukan, set so low in a valley that they see no direct sunshine at all from October to March. Marnie Chesterton heads there to hear about an ingenious solution: giant mirrors that beam rays down into the town square, where locals gather to feel the reflected heat. The man behind the project was motivated by a need for winter sun – but how much difference does it really make to our health and happiness? That’s the question posed by this week’s CrowdScience listener Michael, who has noticed living in the rainy Australian city of Melbourne is taking its toll. Many pensioners claim sunshine relieves achiness as well as conditions like arthritis but one of the biggest scientific studies found temperature actually has no impact on reported pain levels, while factors like air pressure and humidity may play a role. When it comes to our mood, it seems that spending time outside is more important than feeling the heat and the optimum temperature for wellbeing is around a cool 19 degrees centigrade, while excessive warm weather has been linked to an increase in violence and crime.

Contributors:

(Image: Man with smoke coming out of ears. Credit: Getty Images)

CrowdScience investigates the link between music and emotion to try and understand why certain songs can have such a profound impact on our mood.

From breakup songs to upbeat holiday hits, many of us have made playlists that reflect how we feel, whether that’s down in the dumps or high as a kite. This week CrowdScience investigates the link between music and emotion to try and understand why certain songs can have such a profound impact on our mood.

Presenter Anand Jagatia is surprised to learn that newborn babies are more likely to fall asleep when listening to fast tempo happy tunes than soothing sad lullabies, which may be because they’re attuned to multiple auditory stimuli after months in the womb.

But later in life we actually seek out sad songs to make us feel better. The so-called ‘sadness paradox’ has been studied for many centuries. But what is it about melancholy music that might be good for us?

Some scientists believe more empathetic people enjoy listening to these types of tune because they elicit a feeling of compassion towards others, which can be rewarding.

A film composer tells us how scoring suspense isn’t simply about minor or major chords, or even what instruments you use – it all comes down to keeping the audience guessing about what’s coming next.

(Photo: young woman listening to headphones looking sad. Credit: Getty Images)

Presenter: Anand Jagatia

Contributors:

Alex Heffes

“I’m bored!” We can all relate to the uncomfortable - and at times unbearable - feeling of boredom. But what is it? Why does it happen? And could this frustrating, thumb-twiddling experience actually serve some evolutionary purpose?

CrowdScience listener Brian started wondering this over a particularly uninspiring bowl of washing up and it’s ended with presenter Marnie Chesterton going on a blessedly un-boring tour through the science and psychology of tedium.

She finds out why some people are more affected than others, why boredom is the key to discovery and innovation and how we can all start improving our lives by embracing those mind-numbing moments.

(Photo: Bored kids on a park bench. Credit: Getty Images)

Presenter: Marnie Chesterton

Contributors: