Cover art for podcast Discovery


299 EpisodesProduced by BBC World ServiceWebsite

Explorations in the world of science.


How do you make the perfect cup of tea?

A story of sorrow and comfort today, as Doctors Adam Rutherford and Hannah Fry investigate two mysteries sent in by listeners.

The Psychic Tear
Edith Calman challenges our scientific sleuths to answer the following question:
“What is it about extreme pain, emotional shock or the sight of a three-year-old stumbling their way through an off-key rendition of Away in a Manger that makes the brain send messages to the lacrimal glands to chuck out water?"

Hannah discovers how the eye produces tears, with the help of Dr Nick Knight. Broadcaster Claudia Hammond, author of Emotional Rollercoaster, describes why Darwin experimented on his children until they cried. And, Adam watches a tearjerker to take part in a psychological study, but ends up getting angry instead.

The Tea Leaf Mystery
The team examine how to make the perfect cup of British tea, in response to Fred Rickaby from North Carolina:
"When we are preparing a cup of tea and the cup contains nothing but hot, brewed tea we need to add milk and sugar. My wife always adds the sugar first, stirs the cup to make sure it is dissolved and then add the milk. So, is that an optimum strategy for adding milk and sugar to a cup of tea?"

Adam consults Prof Andrea Sella from University College London about the chemistry of tea. Hannah visits a tea factory in Kent where Master Blender Alex Probyn teaches her an unusual method for tasting tea.

They conclude with the most important question: should you add the milk first or last? And, can tea professionals really tell the difference?

If you have any everyday mysteries for the team to investigate using the power of science, please email

Producer: Michelle Martin

Image: A woman holds a cup of tea, Credit: Thinkstock

Educational emoji reaction


Interesting emoji reaction


Funny emoji reaction


Agree emoji reaction


Love emoji reaction


Wow emoji reaction


Are you the creator of this podcast?

Verify your account

and pick the featured episodes for your show.

Listen to Discovery


A free podcast app for iPhone and Android

  • User-created playlists and collections
  • Download episodes while on WiFi to listen without using mobile data
  • Stream podcast episodes without waiting for a download
  • Queue episodes to create a personal continuous playlist
RadioPublic on iOS and Android
Or by RSS
RSS feed

Connect with listeners

Podcasters use the RadioPublic listener relationship platform to build lasting connections with fans

Yes, let's begin connecting
Browser window

Find new listeners

  • A dedicated website for your podcast
  • Web embed players designed to convert visitors to listeners in the RadioPublic apps for iPhone and Android
Clicking mouse cursor

Understand your audience

  • Capture listener activity with affinity scores
  • Measure your promotional campaigns and integrate with Google and Facebook analytics
Graph of increasing value

Engage your fanbase

  • Deliver timely Calls To Action, including email acquistion for your mailing list
  • Share exactly the right moment in an episode via text, email, and social media
Icon of cellphone with money

Make money

  • Tip and transfer funds directly to podcastsers
  • Earn money for qualified plays in the RadioPublic apps with Paid Listens