In the week of the solstice – the shortest or longest day of the year depending on your latitude - Unexpected Elements brings you tales of darkness and light.

We hear about the dark history of sensory deprivation studies and why up until now, we’ve been in the dark about light’s role in the fairly fundamental process of evaporation.

We’ll be shining a light on the darkest oceans, meeting the fantastical creatures who can turn their bodies into flashlights.

Our Under the Radar story this week also comes from the sea as we discover how fish skin is helping to treat burn victims in Brazil.

We have an Ask the Unexpected question about why we don’t sneeze when we’re asleep, and more of your emails and voicenotes about obscure sports, tunnel living and earworms.

We even find time to wonder why the Brazil nut isn’t called the Bolivia nut.

Presenter: Marnie Chesterton, with Camilla Mota and Chhavi Sachdev

Producer: Ben Motley, with Dan Welsh