After the end of a near 17-year legal battle between popstar Katy Perry and fashion designer Katie Perry, the Unexpected Elements team has been inspired to explore the question at the heart of the case – what's in a name?

First, we hear how marmosets use their calls as a way of naming which friend they’re talking to. Then, we discover why a phenomenon known as auditory pareidolia means you can’t necessarily believe your ears.

We're then joined by David Kaiser, professor of physics and history of science at the Massachusetts Institute of Technology, who explains just how hard it is to put physics into words.

Also, the disappearance of indigenous languages, the law for naming laws, and where did all our hair go?

All that, plus many more Unexpected Elements.

Presenter: Marnie Chesterton with Andrada Fiscutean and Michael Kaloki