SciShow explores the unexpected. Seven days a week, Hank Green, Michael Aranda, and Olivia Gordon delve into the scientific subjects that defy our expectations and make us even more curious!
Schedule:
Sundays - Learn about the amazing topics we can't quite make a stand-alone show about in SciShow List Show!
Mondays - Tune in for a short Dose about our weird world.
Tuesdays - Find answers to our most asked Quick Questions.
Wednesdays - Hank or Michael dives deep into a long-form Infusion episode, or an unscripted talk show or quiz show with a guest!
Thursday - Another new dose about the wonders of the world.
Fridays - Learn the latest in science News.
Saturdays - Get your quick questions answered!

Don't forget to check out our sister-channels SciShow Space, SciShow Psych, and SciShow Kids!

  • 2 132
  • 1 113 310 362

Comments

  1. SPOOKS

    thorium cam hardly be considered radioactive, and both thorium and urainium are incredibly good at making energy.

  2. One Person

    This world isn't so great that I'd want to be here forever. Interesting that the bible says people used to live to around 1000 years, but maybe God saw a problem with that as the world got more populated, so he shortened the telomeres? I'd imagine that living a long time would allow one to have a lot of kids to populate the world, but then when that job is pretty much done, you'd want the old folks out of the way to make room for the new ones. Plus, I think there's something better waiting for us after than all the struggle and corruption we have to endure here.

  3. Tersoo Upaa jr

    When the facts go against right wing reactionaries suddenly its feels over reals

  4. Daniel Horn

    'Non-Petisan'

  5. ICA junin

    I feel sorry for vegans in the wild

  6. Jim

    Thank you based god

  7. TheMidnightBanshee 59

    if only all our organs were made of hepatocytes we would essentially be like deadpool

  8. Killerspieler0815

    @SciShow - YES , Germany was great in science before ~1940 ( & one of the leading nations)

  9. Lorisa214

    But t what age?? I've read 40+ is when it can start

  10. Wicked Clown Love

    Oof so break the lab rules and I'll find a discovery

  11. David Thornton

    Unsubscribed.

  12. The CuratedFlame

    If any USsel video deserved a pt.2 its this one! this was awesome to watch

  13. Jonathan Meddis

    My conclusions: Since only masculine and feminine characteristics exist, even if every possible configuration of sex characteristics gets a new name, every new configuration will (almost) inevitably be either biologically masculine or feminine in accordance with a specific set of chromosomes. It's a practical impossibility to have a perfectly balanced configuration of masculine and feminine sex characteristics in an individual and roughly 99% of people will always be clearly either masculine or feminine, presenting chromosomal sex consistency with their phenotypic sex (their internal and external genitalia, expression of secondary sex characteristics, and behavior). Even the majority of DSD (Disorders of Sex Development) individuals present chromosomal sex consistency with phenotypic sex and are still considered clearly masculine or feminine, although they may present some degree of intersex traits. An individual can be defined truly intersex only when chromosomal sex is inconsistent with phenotypic sex, or in when the phenotype (observable sex characteristics) is not classifiable as either masculine or feminine. Those are less than 1% of people. The ULTIMATE Answer: How many sexes do humans have? It depends... It depends on what contextual definition of "sex" are we implying with the question. If our contextual definition of sex is strictly correlated to Evolutionary Reproductive Roles (current scientific convention) the answers is: Two. Male and Female. Because (in humans) Evolutionary Reproductive Roles are a binary system, and I think it's crucial to clarify that by "Reproductive Roles" I'm not referring to the "potential" for reproduction that humans have. Because clearly there are humans that for whatever medical reason are not able to reproduce. By Evolutionary Reproductive Roles I'm referring to the biological reproductive system designed by evolutionary natural selection that allows the human species to procreate and pass genes on. And that's binary (Male role & Female role, sperm production & egg production/gestation, chromosome X & chromosome Y). However... If our contextual definition of sex does NOT imply Evolutionary Reproductive Roles the answer is: Any possible configuration of sex characteristics can technically be classified as sex, and this Spectrum is of course is inclusive of intersex people and any other atypical configuration. HOWEVER... While some atypical configurations may not have the same BIOLOGICAL evolutionary reproductive value, EVERY single configuration of sex characteristics has the same HUMAN Value. Everyone deserves the chance to feel accepted, worthy of being alive and comfortable with their bodies and identity. So the ULTIMATE answer is: It doesn't really matter what kind of sex you randomly happened to get. Just don't be a d1ck :)

  14. chelar estelar

    Well, mine just seems to be working all of it at half capacity

  15. Matt Peacock

    does the flavor of sperm stay awesome??? Asking for a friend, I don't care for the flavor, STOP JUDGING ME!

  16. sEkKi

    top 5 worst computer viruses #1 system32

  17. ben andre

    crap

  18. Nick August

    Your dirty glasses are distracting me as I cant believe how you dont get annoyed by it.

  19. Alluz

    Number 1 is the PUP.optional

  20. kostasifa

    THE WORMS GOT HANK NOOOOOI

  21. ARTEMIS HAYDEN

    It’s like Kratom, legal in the US on a federal level but a few states banned it.

  22. 1SmokedTurkey1

    Truffles are regularly grown in the Netherlands (magic truffles).

  23. FemmeTresBelle FemmeTresBelle

    I'm sitting here with 3 cats and a dog. They all looked up with concern, upon hearing the 52 blue whale. My oldest cat wanders the halls making the same sounds when he's lonely. It gets everyone's attention.

  24. Latoya Clarke

    This happened to me.

  25. Persian Music

    My ex girlfriend ?

  26. SuperRegic

    They hated him because he told the truth

  27. oak

    at least one rock at Racetrack moved in a complete circle, kinda making the ice layer explanation a bit of a stretch....

  28. John Smith

    drink your pomegranate juice, kiddies!

  29. Tricia Fleckenstein

    I grew up near Love Canal! It was crazy for sure. They rebuilt a school in too of the canal inspite of warnings!

  30. Joshua Jarvis

    Insects don't wear jackets. Yellow jackets lied to me!

  31. Uncle

    Eating snow is perfectly fine

  32. K Dobermann

    No mention of telomere length increase huh? Interesting you left that tidbit out.

  33. Andrew Peter

    Plants r like are these humans stupid or what, this is supposed to be poison😅😅

  34. Howard Maryon-Davis

    Predictably this presentation, from a reliably sound science based channel, has polarised opinion. The problem is, that people of the persuasion that gender is about what you feel like, will somehow assume that this program justifies their mental illness.

  35. Electric_ Mic

    I somehow question these to my self today and look it up on USsel thanks for the infi

  36. Tyler Stevens

    If it's climate change why is the issue hitting just western countries? Or is it that we don't have the same quality of data for everywhere else?

  37. Jackson Stein

    Water???

  38. Matt Erickson

    just don't make videos about human sex if you're too afraid to talk about properly

  39. Njörðr Sigurðr

    Hey Hank! Do you know what they call ppl without face hair? Women!

  40. Matthew Hargis

    Your description is even maddening because you're basically saying that believing in sexual reproduction is a childish understanding of biology.

  41. ReaperEOD

    It doesn't sit right to me that SciShow is selling 'facts' without directly citing sources in the time of their claims. And before anyone here starts saying "sources are in the description", any good science channel ALWAYS puts an annotation directly to sources so that there is transparency to what source they are citing. i.e. Hank, twice in the video, says "in fact", with no annotations, in the first two minutes of the video. And before anyone says "there are 31 sources!".. have you checked the sources? Do you also realize how many scientific articles are published a day? And if you actually check the sources, some of them are simply journals, opinion pieces, and yes, checking these sources actually contradict even the simple terminology where Hank says intersex is now called DSDs, because the Intersex Society of North America (not a scientific source, ISNA), actually defined intersex and DSDs actually as TWO DIFFERENT THINGS. So if you do your research and try to follow up the claims made in the video, in the first two minutes, you already find contradictory information within their own cited sources. Notice none of the sources were written with what information was pulled from where, so if we really as a group want to review and justify their information, SciShow just hid away all their information in sources. For example if I claim that intersex is 1 in 2000 and actually 0.0005%, I can show you that link. And guess what? It's one of SciShow's sources: isna.org/faq/ten_myths/rare/ I'm being transparent about what information I got from that source, but what is also true? The ISNA define intersex and DSDs as two different things, something Hank apparently is selling differently. And guess what? The ISNA actually don't even like the terms hermaphrodite, nor even the term ambiguous genitalia, sources here: isna.org/faq/ambiguous/ isna.org/faq/hermaphrodite/ Don't trust something not being transparent with blind faith, please. Check the sources, do your own research, come to your own conclusions.

    1. Tersoo Upaa jr

      Reeeee why doesn't science agree with me.

    2. Jonathan Meddis

      My conclusions: Since only masculine and feminine characteristics exist, even if every possible configuration of sex characteristics gets a new name, every new configuration will (almost) inevitably be either biologically masculine or feminine in accordance with a specific set of chromosomes. It's a practical impossibility to have a perfectly balanced configuration of masculine and feminine sex characteristics in an individual and roughly 99% of people will always be clearly either masculine or feminine, presenting chromosomal sex consistency with their phenotypic sex (their internal and external genitalia, expression of secondary sex characteristics, and behavior). Even the majority of DSD (Disorders of Sex Development) individuals present chromosomal sex consistency with phenotypic sex and are still considered clearly masculine or feminine, although they may present some degree of intersex traits. An individual can be defined truly intersex only when chromosomal sex is inconsistent with phenotypic sex, or in when the phenotype (observable sex characteristics) is not classifiable as either masculine or feminine. Those are less than 1% of people. The ULTIMATE Answer: How many sexes do humans have? It depends... It depends on what contextual definition of "sex" are we implying with the question. If our contextual definition of sex is strictly correlated to Evolutionary Reproductive Roles (current scientific convention) the answers is: Two. Male and Female. Because (in humans) Evolutionary Reproductive Roles are a binary system, and I think it's crucial to clarify that by "Reproductive Roles" I'm not referring to the "potential" for reproduction that humans have. Because clearly there are humans that for whatever medical reason are not able to reproduce. By Evolutionary Reproductive Roles I'm referring to the biological reproductive system designed by evolutionary natural selection that allows the human species to procreate and pass genes on. And that's binary (Male role & Female role, sperm production & egg production/gestation, chromosome X & chromosome Y). However... If our contextual definition of sex does NOT imply Evolutionary Reproductive Roles the answer is: Any possible configuration of sex characteristics can technically be classified as sex, and this Spectrum is of course is inclusive of intersex people and any other atypical configuration. HOWEVER... While some atypical configurations may not have the same BIOLOGICAL evolutionary reproductive value, EVERY single configuration of sex characteristics has the same HUMAN Value. Everyone deserves the chance to feel accepted, worthy of being alive and comfortable with their bodies and identity. So the ULTIMATE answer is: It doesn't really matter what kind of sex you randomly happened to get. Just don't be a d1ck :) (not you specifically, I'm just sayin' :P)

  42. John Takolander

    The dumbest Nobel: Pierre Curie and the Curie point. It was discovered by Gilbert and Faraday!

  43. evelyn bagnasco

    I don't want to see a human talking, I want to see the sea creatures, full screen please.

  44. Yifo123

    I think gonnorrhoeae is everyone's kryptonite, not just superman

  45. Rob Brenton

    Huhuhuhhuhuhu. You said sperm. Uhhh huhuhuhhuhuhu .....

  46. John Fischer

    Why say a video suggestion but not have it tagged?

  47. Abraham Mauritz

    you do not know what you are talking about you think you do

  48. Grapes

    I wonder if people have jobs scooping ant clumps into lidded buckets

  49. wdd3141

    Twice "climate change" is mentioned here matter-of-factly. But not all scientists have a gun to their head held by politicians and government grant groups with career-ending threats, and some of them are legitimately "skeptics" who comment when the special interest groups fudge (read: "falsify") the data to fit the narrative. Tony Heller is a generous source of information on this matter, and he doesn't sound like a tin-hat crackpot.

  50. Lucky Loonies

    The problem is the male reproductive biological clock is not the same as the female reproductive biological clock, the female reproductive biological clock ends near the middle of their life expectancy . The male reproductive biological clock cause the sperms to deteriorate after the man had become sexual matured and will continued to do so thronghout the man's entire life. There is zero chance for an 80 years old lady to became pregnant but it is possible for an 80 years old man to impregnate a woman of the sexual reproductive age.

  51. X T

    8:54 nice roast at the end. 😂

  52. Marius Garcia

    I didn't subscribe nor pressed the notification bell? Hmmm... Someone's tying to push an agenda.

  53. Pavel

    Ageist video

  54. Red H

    Any particular age ranges where one should worry about? Also, is there such thing as negative effects on sperm for being too young?

  55. Eric Cartman

    Imagine being forced to eat a tonsil stone burger

  56. Kittn Playz

    And this is why i dont eat soda

  57. Robert Willis

    Right every animal has mutations that's what he is actually saying, mutations are not to be taken as normal. They are abnormal anomalies.

    1. Jean Scuissiato

      You are a mutation from a bacteria. You are a abnormal anomaly.

  58. i got a big shirt

    *WHY DID I TAP ON THIS*

  59. 2VerySnowy

    I was always told to lean forward with a tissue on my nose I was also to,d to pinch my nose

  60. CIRUS MEDIA

    This video is way too PC for me to enjoy... it's killing our science!

  61. Ty Yeager

    So to summarize the video, there are two sexes. Sometimes there are errors in development that cause some different disorders in which the people who have them live happy lives. Now to be “politically correct” and “forward thinking” we say sex is a spectrum. If someone was born missing a limb, we wouldn’t say humans have 3 limbs, we would say they were born with a disorder.

    1. Tersoo Upaa jr

      Reee why doesnt science man agree with me.

  62. 2ManyLayersOfIrony

    Nice likebotting

  63. Jefferson Stinson

    What's wrong with your nose?

  64. The Guy With a Y

    This video was a waste of time. Provided me no factual value and rambled with a script that I can write in two seconds.

  65. Peter Seidel

    Huckleberry Finn. Now I get it

  66. TheMidnightBanshee 59

    wow first superconductors now superfluids

  67. E The incredible kid

    Dammm i waz right

  68. Ashan Ariyawansa

    Is this the son of Dwight ?

  69. Jon

    84mg of caffeine for me is strong already. My tolerance is low

  70. Mr Roderick Jaynes

    0.87% THC in the state the flower is in, the rest of the THC is at that point THCa, a carboxylic acid group is attached to the THC molecule. What this means if you were to just eat that bud, only 0.87% of it is psychoactive in that state. Upon decarboxilation, usually via heat, that group is stripped off the rest of the molecules and if conversion of every molecule of THCa to THC were to happen, then it would have accounted for 18.9% of the original mass. For a vast majority of people the Total THC is the relevant number, and the other can be ignored. In some US states they make it even more confusion by doing a listing of THC, THCa and Total THC, and since THCa weighs more than THC people get very confused that the THC + THCa doesn't equal total THC.

  71. James Darwin

    Are you looking for an Honest and Responsible Bitcoin Investment Company with Excellent Investment Plans and Multi-level Marketing? Start Today at coinvalueexpress.com With years of experience with investing BTC myself, I can say I make a nice passive income for myself. I always invest on the safe side so I do not invest in HYIP`s for example.

  72. Lily Powell

    Isn't Edison the one who stole Tesla's ideas !??

  73. Der1heiss1Musiker96

    What about endorphines released on sweat? It is well studied that women release it and even it is responsible for regulating menstrual cycle when living with other women. Could the opiate system work as a “pheromone” system?

  74. Дмитрий Веселов

    We need separate terms to distinguish biological reproduction investment dimorphism and all those "who you are attracted to" stuff. If we refer to "sex" as intra-speices reproductive strategy - then there are either two of them or zero. Sex is an amount of biological investment into reproduction process. So the species can have either two sexes (males who invest less and females who invest more) or zero sexes (equal investment into reproduction). If we refer to "sex" as "who do you prefer to have relationships with" then there is obvious some traits of preference and huge variability in combination of those traits. If we mix these things into the same word "sex" then we get into trouble, because this term confusion overlaps with the eternal societal dilemma between evolving and preserving.

  75. TheMidnightBanshee 59

    my moto why the hell would I wear something just because everyone else is wearing it I aint the idiot in skin tight jeans

  76. Zds Let's Plays!

    So, this question may be inappropriate. But does this mean that fully functional/developed futanaris actually exist?

  77. meatrace

    Irresponsible and wildly inaccurate Hank. I'm ashamed of you.

  78. gamergirl209

    I had a switch a few years ago that meant I was doing a lot of driving between 11pm and 2 am. I never saw as much lightning as I did during those hours. No rain no thunder, just tons of lighting arcing across the sky. Any ideas?

  79. TOCKRELL MAN

    Can you guys make a video on this “Artificial Leaf” that’s been all over the news?

  80. Bigchungus 1

    200 liver

  81. Merry Machiavelli

    The endless contorting to avoid the terms 'men' or 'women' within the video, or even 'male' or 'female' is clunky. I couldn't even finish watching it was so irriating. Avoiding basic (99% accurate) terms that refer to human sex in favour of ambiguity in an effort to be 'sensitive' to a tiny proportion of the human population (most of whom probably wouldn't really mind anyway) is excessive. Please stop doing it.

  82. Filip Krasilnikoff

    Dang, I was hoping for some Hard Light progress. Oh well, smoke me a kipper, I'll be back for breakfast.

  83. Chef Bain90

    5 deadliest bacteria exist in food can make you sick for a month also. .. . ussel.info/video/video/1qiumXefzKqpaH0.html

  84. NGTASSASIN

    Bring tht cat to New York they have a rat problem

  85. Vital Chance

    ahaha 9:09

  86. furrtakuXD

    so there are two sexes. the egg producers and the sperm producers. they tend to look distinct from each other. some people (2%) can look like one but function as the other, have intermediate features, have mixed or opposite reproductive structures, and either function or not function reproductively. a much larger but still small percent may also lack function for other reasons if anything it proves that humans are only capable of two sexes since these basically just remix the features from two larger more common groups

    1. Joe Constantine

      @Bloodrush so there are two hair colours, blonde and brown, yeah?

    2. Bloodrush

      @NinjaSquirel99 so?

    3. NinjaSquirel99

      You do realize a lil less than 2% of the population is ginger right?

  87. hi ._.

    4k dislikes are from Facebook Karens

  88. Pa Pinkelman

    The ability to impregnate ones partner at the age of 90 has more to do with ones bankaccount. Just an opinion.

  89. Nugroho RF

    So at what age should I make a new human?

  90. Karma Kuro

    HAHA! Chuds triggered by science disliking like crazy! Good to know likes still out shadow the dislikes

  91. WHATISF3AR

    Good job hank! Keeping it scientific!

  92. Spy Fox

    I love ice on my cock

  93. Pamela Jade

    I'm confused on how the b12 affect the sperm, can someone explain that to me a bit simpler ?

  94. Anarchy Antz

    Breathe through your butt and pee through your mouth. I think mother nature was a bit drunk that day.

  95. Dr. Andrew Joseph Pegoda

    Excellent and informed video.

  96. ORDINARY ENTHUSIAST

    Arent we taught this in school. Is this really new.

    1. Peter Gingerelli

      Depending on your age and school. Honestly

  97. CombatosFantasyBattles TCG

    My cat is to old to be interested to catnip.

  98. Dzeljana Pusiga

    Excellent video content! Excuse me for the intrusion, I would love your initial thoughts. Have you heard the talk about - Parlandealey Mouth Cure Process (do a search on google)? It is a good exclusive product for learning how to cure tonsil stones minus the headache. Ive heard some incredible things about it and my best friend Jordan after a lifetime of fighting got great success with it.

  99. Rumpel Felt

    Meh I think my plan of no kids until my 40's is still viable

  100. E Money

    Good one!