After North Korean balloons delivered trash to South Korea, we explore balloons of all kinds, why they can be useful, and when they’re not.

Scientists have been using balloons for a long time, from pig bladders dropped from great heights, to Michael Faraday inventing the rubber balloon.

Floating through the air seems like a great, energy-efficient way to fly. So why isn’t the sky full of airships?

And party balloons are fun… but do we want to waste our precious helium on parties? What is this limited gas worth saving for?

Also, why you’re likely smarter than your grandparents were at your age, why snails climb up walls, and scientists looking at clouds from space.

Presenter: MarnieChestertonPanellists: Andrada Fiscutean, Meral JamalGuests: Prof Andrea Sella (University College London) and Prof Dave Hodgson (University of Exeter)Producer: Florian Bohr with Harrison Lewis, Julia Ravey and Noa Dowling