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How big is a rainbow?
CrowdScience
Nov 28, 2025

When listener Sakura’s husband came home from his morning walk in Cambridgeshire, UK, he told her about a massive rainbow he’d seen. But when he showed her a picture, she didn’t think it was particularly large. So how big is a rainbow really? Are they always the same size? And if some are bigger than others, is there a limit?

To find the answers, presenter Marnie Chesterton meets independent rainbow expert Philip Laven in a pitch-black studio to simulate how a rainbow is formed. He demonstrates how they are created by sunlight, reflecting and refracting in millions of little water droplets.

But what does that mean for their size? Raymond Lee, retired professor from the US Naval academy, says that rainbows are not objects and don’t have a linear size, just a specific angular size that’s relative to the person seeing it. But Marnie doesn’t give up so easily – some rainbows still look bigger than others.

In her journey to discover other ways to size up a rainbow, Marnie hears from Australian aerial photographer Colin Leonhardt who stunned the world with a beautiful picture. Next, assistant professor Ping Wah Li from The Chinese University of Hong Kong explains why it’s possible to come across more than one rainbow at a time.

And finally, atmospheric scientist Harald Edens shares another way to consider size, as well as how much he struggles to explain the complexity of rainbows to his four-year old daughter.

Presenter: Marnie Chesterton

Producer: Florian Bohr

Editor: Ben Motley

Photo: Rainbow of Dreams - stock photo stock photo Credit: Laurent Fox via Getty Images)

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Jun 5, 2026
Do plants have personalities?

CrowdScience listener George is showing Alex Lathbridge around a small, dark, and extremely hot shed, just outside the city of Accra in Ghana. Inside are row after row of shelves, stacked high with bulging grow-bags. And out of some of them, gorgeous cascades of oyster mushrooms are bursting into bloom.

We’re on George’s mushroom farm, and he’s noticed something interesting. Even though the conditions in his grow-shed are tightly controlled – they have exactly the same food, water, and light as each other – nevertheless, they respond differently. Some are more vigorous than others, some bloom quicker, others last longer, and some are more tolerant when the conditions change. And this got George wondering. Could ‘brainless’ lifeforms like mushrooms, and plants, have different ‘personalities’? Do they experience the world differently, and live their lives differently from each other? Alex Lathbridge is on the case.

He visits the PGRRI, the Plant Genetic Resources Research Centre, for a quick lesson on genetic variation in the plant world. Plants are all different at the genetic level, and it’s those differences which can result in a tastier fruit, or a hardier crop. But would we call traits like these personality?

In the Minimal Intelligence Lab in the University of Murcia in Spain, Paco Calvo thinks that we absolutely should. He studies plant intelligence, and points Alex to a whole host of examples of plants being smart in ways which might surprise you. Each one is an individual, and if we can only slow down enough to appreciate them properly, we’d be able to understand them better too.

Back in Ghana, Alex meets plant physiologist Dr Acheampong Atta-Boateng, in the beautiful grounds of Aburi Botanical Gardens, to meet some of these plants for himself. And he discovers that there’s a whole world of smart, resilient, and resourceful little organisms in the plant world, full of personality, if you know where to look. Who needs a brain!?

Presenter: Alex Lathbridge

Producer: Emily Knight

Editor: Ben Motley

(Photo: Drawing of a face and smiling eyes on a sunflower flower - stock photo- Credit: Jose A. Bernat Bacete via Getty Images)


29min 16sec


May 22, 2026
Why am I an introvert?

CrowdScience listener Daniel in Accra, Ghana is an introvert. Or at least, he thinks he is. And he’s worried that his preference for quiet spaces and lower social interaction might be holding him back in life. But what is introversion really? How do introverts and extroverts see the world differently? And is it better to be one or the other?

Presenter Alex Lathbridge spends his working days talking to interesting people like Daniel. He loves meeting people, and talking to them too, yet he also thinks that deep down, he might be an introvert. To understand how and why people come to be introverted or extraverted, and what’s happening in the brain, he pays a visit to neuroscientist Dr Thomas Tagoe from the University of Ghana Medical school, for a peek inside the mind. Turns out, introverts aren’t shy, and definitely aren’t anti-social either, despite what people might assume. The difference is more about how we process stimulation, and at what point we find it all a bit too much to process. Although sometimes it might feel like the world is built for the extraverts out there, Thomas offers some reassurance. There are huge benefits to being introverted too, and there’s room in the world for all the different personality types to thrive.

But how about in the workplace? Daniel is worried that his introversion could be holding him back at work. He feels like being good at your job is not always enough – you need to be able to network, charm people, and “work the room” if you want to succeed. So, Alex heads for the Methodist University of Ghana to meet Professor William Baah-Boateng, who has studied the effect of all the different personality types on their performance in the workplace. Is there a place for the introverts of this work to make their mark?

Presenter: Alex Lathbridge

Producer: Emily Knight

Editor: Ben Motley 

(Photo:A view of a woman's eye looking through a hole in some colorful paper-Stock Photo - Credit:PeopleImages via Getty Images)


26min 28sec


How big is a rainbow?

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