Series 2, Episode 01: FLUSH AND FORGET
If you’re using the player above to listen to this episode, click here to open this page in a new browser window so you can visit the links below without losing your place.
In this episode, Steve discovers the greedy cup siphon hiding inside your loo, Matt delves into Joseph Bazalgette’s calculations for London’s sewer system and Helen teaches everyone how to flush a toilet, through the medium of song.
- 00:48 – Steve’s bit
- 11:48 – Helen’s bit
- 28.03 – Matt’s bit
This series is sponsored by Brilliant.org, the place to learn maths and science through interactive online lessons. Start your free trial at Brilliant.org/apoud, and the first 200 Unnecessary Detail listeners who sign up for annual membership will get 20% off on the same link.
If you’d like inbox updates about this podcast and our plans for future live shows, join our mailing list. If you’re into merch, DVDs, downloads or books check out the Spoken Nerd Shop. If songs are your thing, Helen has created a free album on Bandcamp with all the tracks from Series 1 and 2.
Corrections and clarifications:
- Listener Alex Purcell has pointed out another place where greedy cup siphons can be found… inside condensing boilers.
- Matthew has suggested Crossness Pumping Station in South East London as a great family day out – which Helen can confirm as she’s been there several times now. Book your guided tour or open day visit here! Or if you can’t visit, Tim Traveller takes you round it on YouTube, though obviously ignore the bit about how Bazalgette calculated those sewer diameters…
- If you want even more detail about what happens to London’s effluent after it leaves Bazalgette’s underground sewers, and whether low water use, biogas-generating toilets are the future, this Radio 4 documentary from Helen has plenty.
- If you enjoy touring sewers around the world, listener Oliver Tasche has suggested Cologne (check out the Chandelier Hall!) and listener Youenn Fenard recommends the “Musée des égouts de Paris“
- Mikael Glamheden emailed from Sweden with a very nicely designed seesaw-style toilet flush. It’s clear, intuitive and accessible. Well done, Swedish design! See below for a picture.
- Meanwhile, Jaimie Ritchie emailed us an utterly unintuitive toilet flush, as seen in the wild. Any clues about how this works, or confirmation about whether it’s even been installed properly or not, would be very welcome. Pics below!
And here’s a heap of Unnecessary Detail from this episode:
- A North American toilet flushing.
- A British toilet flushing.
- Steve’s video The Pythagorean Siphon Inside Your Washing Machine.
- Steve and Matt in I Made A Water Computer And It Actually Works.
- What is a Soxhlet extractor?
- Watch Helen’s song Oh My God I Don’t Know How To Flush A Toilet on YouTube.
- Lyrics and free download are here on Helen’s bandcamp page.
- If you have 15 minutes, listen to this BBC Radio 4 documentary that Helen about how the Victorians ruined toilets for everyone, forever.
- “Brits admit they don’t know how to flush a toilet“
- ISO symbol “To identify the control to flush the toilet after defecation“
- ISO symbol “To identify the control to flush the toilet with a small amount of water after urination” (both found for us by the brilliant @chellaquint)
- The Australian inventor of the dual flush toilet, Bruce Thompson.
- Original workings from “The Calculations Of Mr Bazalgette”, title page and page 24. See also the key calculation below.
- The Museum of London looks at Bazalgette’s original sewer designs.
- “The big clean-up of London’s sewage system is underway“
- Tideway: London’s Super Sewer.
A Podcast Of Unnecessary Detail is part of the Acast Creator Network. Thanks for listening!