Episodes

  • ELI5 Fire Extinguishers - why are they red in color?

    ELI5 Fire Extinguishers - why are they red in color?
    Feb 6 2026
    Why is most fire equipment red in color? What happens if you use the wrong class of extinguisher on a grease or metal fire? Could the future of firefighting be a "dubstep cannon" that uses sound waves to kill flames? ... we explain like I'm five Thank you to the r/explainlikeimfive community and in particular the following users whose questions and comments formed the basis of this discussion: jasonthefuzz, jebediah_johnson, rtpkickballer, audiblenod, markhunt1980, mpls_is_rivendell, dvn_rvthernot and dignitty. To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Join us on Twitter: https://www.twitter.com/eli5ThePodcast/ or send us an e-mail: ELI5ThePodcast@gmail.com
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    8 mins
  • ELI5 HRV - What is heart rate variability and why can a steady heartbeat be trouble?

    ELI5 HRV - What is heart rate variability and why can a steady heartbeat be trouble?
    Feb 2 2026
    Why does a perfectly steady heartbeat actually serve as a warning sign you should not ignore? If your heart is a drummer, why is a little bit of "bad timing" a good thing? How can your smartwatch tell you are stressed before you even feel it? Why does splashing cold water on your face trigger an ancient, "hidden" survival reflex? Why did Neil Armstrong’s heart race to 150 BPM while his co-pilot stayed totally calm? ... we explain like I'm five Thank you to the r/explainlikeimfive community and in particular the following users whose questions and comments formed the basis of this discussion: iacuriousguy1968, quesoqueso, elderberry2, spooky_fellow, swolemedic, uptowntwerk, narwhalondrugs and alternative-sea-6238 To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Join us on Twitter: https://www.twitter.com/eli5ThePodcast/ or send us an e-mail: ELI5ThePodcast@gmail.com
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    9 mins
  • ELI5 Palladium - more valuable than gold?

    ELI5 Palladium - more valuable than gold?
    Jan 16 2026
    Why is a metal you’ve probably never heard of often worth more than pure gold? Why are thieves risking jail just to steal one specific part from a Toyota Prius? What is the "Palladium at Night" satellite doing that no government will admit to owning? How did Ford lose a billion dollars by trying to hoard this "ghost" metal? Could this strange metal be the secret to "cold fusion" and unlimited power? ... we explain like I'm five Thank you to the r/explainlikeimfive community and in particular the following users whose questions and comments formed the basis of this discussion: tmwnn, jonathanrdt, audiblenod, iwillnevergetaname, tutul_, brokeneye3, cortcortkittycat and lwbdrb0901 To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Join us on Twitter: https://www.twitter.com/eli5ThePodcast/ or send us an e-mail: ELI5ThePodcast@gmail.com
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    9 mins
  • ELI5 Jevons Paradox – why adding more lanes to a highway can make it worse?

    ELI5 Jevons Paradox – why adding more lanes to a highway can make it worse?
    Jan 9 2026
    Why does adding more lanes to a highway actually make traffic jams get even worse? How did the machine meant to end slavery accidentally make it ten times more profitable? Why did the invention of the ATM lead to more bank tellers instead of replacing them? Is your "eco-friendly" car actually causing you to burn more fuel than your old one? Why does being the most efficient worker in the office always result in being given more work? ... we explain like I'm five Thank you to the r/explainlikeimfive community and in particular the following users whose questions and comments formed the basis of this discussion: environmental_bus507, sharp_simple_2764, zem, m1ss1ontomars2k4, nowhereman136 and mammoth-mud-9609 To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Join us on Twitter: https://www.twitter.com/eli5ThePodcast/ or send us an e-mail: ELI5ThePodcast@gmail.com
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    8 mins
  • ELI5 Titanium - why is it the metal most used in surgeries?

    ELI5 Titanium - why is it the metal most used in surgeries?
    Jan 2 2026
    Why did the CIA secretly buy Soviet metal to build the very plane designed to spy on them? How does a metal named after Greek Titans manage to fuse physically with living human bone? If titanium is the ninth-most abundant element on Earth, why is it still so expensive to produce? And how did common chlorinated tap water nearly destroy the manufacturing of the world’s fastest titanium jet? ... we explain like I'm five Thank you to the r/explainlikeimfive community and in particular the following users whose questions and comments formed the basis of this discussion: mattau93, bigaddam, barath_s, icowboy, justscottaustin, 1fresco, qininator and cheapseats91 To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Join us on Twitter: https://www.twitter.com/eli5ThePodcast/ or send us an e-mail: ELI5ThePodcast@gmail.com
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    8 mins
  • ELI5 Xmas - how and why NORAD tracks Santa (part 2)?

    ELI5 Xmas - how and why NORAD tracks Santa (part 2)?
    Dec 20 2025
    Why do people in the UK typically say Happy Christmas while in America it is most commonly Merry Christmas? What made red and green Christmas colors? Is it true that Coca-Cola popularized the modern look of Santa Claus? Why do most of our "traditional" Christmas songs, images and TV/movies come from the 1940s to the 1960s? Brian Earl from the Christmas Past podcast joins us to ELI5 a range of Xmas questions. ... and we explain like i'm five! Help more people fund us by leaving a rating on iTunes. Thank you to Brian Earl from the Christmas Past podcast. If you'd like to hear more excellent xmas episodes, check out Brian's podcast here: https://christmaspast.media/ To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Join us on Twitter: https://www.twitter.com/eli5ThePodcast/ or send us an e-mail: ELI5ThePodcast@gmail.com
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    8 mins
  • ELI5 Xmas - why some say Happy Christmas vs Merry Christmas (part 1)?

    ELI5 Xmas - why some say Happy Christmas vs Merry Christmas (part 1)?
    Dec 19 2025
    Why do people in the UK typically say Happy Christmas while in America it is most commonly Merry Christmas? What made red and green Christmas colors? Is it true that Coca-Cola popularized the modern look of Santa Claus? Why do most of our "traditional" Christmas songs, images and TV/movies come from the 1940s to the 1960s? Brian Earl from the Christmas Past podcast joins us to ELI5 a range of Xmas questions. ... and we explain like i'm five! Help more people fund us by leaving a rating on iTunes. Thank you to Brian Earl from the Christmas Past podcast. If you'd like to hear more excellent xmas episodes, check out Brian's podcast here: https://christmaspast.media/ To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Join us on Twitter: https://www.twitter.com/eli5ThePodcast/ or send us an e-mail: ELI5ThePodcast@gmail.com
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    10 mins
  • ELI5 Pearls - how does a grain of sand make such treasure?

    ELI5 Pearls - how does a grain of sand make such treasure?
    Dec 12 2025
    What makes a pearl so mesmerizing, and what is it really? What exactly is a pearl made of, and how does it form inside a mollusk? Can a grain of sand truly cause a perfect pearl? What's the difference between a natural pearl and the cultured ones we see today? How do pearls get their stunning array of colors, from soft pinks to deep blacks? What makes certain pearls incredibly valuable, fetching millions? ... we explain like I'm five Thank you to the r/explainlikeimfive community and in particular the following users whose questions and comments formed the basis of this discussion: emoposer, iamkunii, cooldrummer1208, Albres, discordant_rhyme, xentonian, enzio901, n19h7m4r3 To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Join us on Twitter: https://www.twitter.com/eli5ThePodcast/ or send us an e-mail: ELI5ThePodcast@gmail.com
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    7 mins