3 Perplexing Physics Problems

  • Published on Nov 20, 2019 veröffentlicht
  • Why does shaken soda explode? Does ice melt first in fresh or salt water?
    Thank you Squarespace for sponsoring this video. Go to squarespace.com to save 10% off your first purchase of a website or domain using code: VERITASIUM
    This video features experiments that have been shown to me by science teachers over the years. Does ice melt fast in salt water or fresh water was an experiment introduced to me at the Utah Science Teachers' conference. The ring of metal over a chain demo came from a teachers event in Florida. The idea shaking a carbonated drink increases pressure came from an email.
    Special thanks to Petr Lebedev for building the pressure gauge.
    Links to literature are below:
    Victims of the pop bottle, by Ted Willhoft. New Scientist, 21 August 1986 p.28
    Carbonation speculation
    The Physics Teacher 30, 173 (1992); doi.org/10.1119/1.2343501
    Agitation solution
    The Physics Teacher 30, 325 (1992); doi.org/10.1119/1.2343556
    Filmed by Cristian Carretero, Jordan Schnabel, Jonny Hyman, and Raquel Nuno
    Music from epidemicsound.com "Seaweed" "Quietly Tense" "Mind Shift" "Observations"

Comments • 6 159

  • MathPhile
    MathPhile 10 minutes ago

    Loved the Ring and Chain trick !

  • Isuzu Slider
    Isuzu Slider Hour ago

    Trick question? It doesn't increase?

    • Isuzu Slider
      Isuzu Slider 59 minutes ago

      HA! I always thought it increased. XD

  • raheeljessa
    raheeljessa Hour ago

    Loving the glass he's using for the coke!

  • Christopher Sanders
    Christopher Sanders 4 hours ago

    Darn paper straws making my soda flat!

  • Ru5ty
    Ru5ty 6 hours ago

    Who wants to see the ice cube experiment again but gently putting it in the water instead of dropping it in?

  • Tim Taylor
    Tim Taylor 6 hours ago

    4:15 best sound ever

  • Mitch Gunzler
    Mitch Gunzler 6 hours ago

    There is another potentially interesting effect going on with the ice cubes. Because the salt water is denser, the ice cube in it displaces less (salt) water than the ice cube in the fresh water. Which means more of the surface is adjacent to air instead of water. (Compared to water, air is a thermal insulator.) That ice cube dips less of itself into the hot bath, if that helps people picture themselves in a similar situation.

  • Chronic Cynic
    Chronic Cynic 7 hours ago

    Okay, so his explanation for why the ice cube melts faster in freshwater, than salt water, never really zeroed in on what's happening. The ice cube in the freshwater glass, would indeed be sinking deeper than the one in salt water. But it's not because "cold water from the ice cube is more dense than the fresh water surrounding it" . In fact, he's focusing on the wrong glass entirely. Adding salt to water increases its density. It's that increased density that keeps the ice cube closer to the surface, resting in it melting slower. So his observations of what was happening were correct. He just never identified the root cause responsible for what he was observing.

  • Looking In With Victor B

    Maybe you can explain Newton's third law.
    When I hear people on Clip-Share like Kyle Hill and MatPat use the F=am calculation to explain Newton's third law, they tend to conclude that the Force exerted by a moving object to an object at rest is in equal proportion, giving them drastic results.

    However, from my understanding, this can't be since, similar to energy conservation, the Force exerted becomes dissipated by outside influences, like the density of what you're hitting, as well as what both objects are braced on, muscles absorbing the shock, etc.

    That said, when I ask whoever is quoting Newton's laws and F=am to elaborate, I get no reply... Any chance of explaining the truth about applying F=am to a collision?

  • Bill Shireman
    Bill Shireman 8 hours ago

    5:24 there is a bug on hisfinger that then flys through the ring

  • Balasubramaniam Natarajan

    I would like to know what would happen if the surface tension of water floating as a sphere is broken, would it unravel ? As a kid I used to attach camphor at the end of a plastic OHP sheets shaped like A and let it loose in water which will cause the A shaped OHP to move on the surface of water. Now I need to know what would happen if that is made to stick to a sphere of water, would it go around the sphere of water ?

  • windlesSpice
    windlesSpice 10 hours ago

    if a 2 liter bottle was complete filled with coke, with no air at the top, it wouldn't explode when you shake it?

  • A F
    A F 11 hours ago

    1. when i was younger. i used to mix ajack non bleach with dish liquid. the aftermath was the smell of ammonia. for years i thought i was crazy. one day in 11th grade chemistry class. a classmate told this same story and the room lit up. several of us said we had done the same thing. Our chemistry teacher told us it was not even possible, since neither of them contained ammonia. ARE we all crazy? what is going on with these two chemicals?

  • Fayetal Attraction
    Fayetal Attraction 12 hours ago

    with the salt water cube, you can actually see the freshwater floating on top of the salt water without food colouring. theres a shot around 6:36 which shows it pretty clearly with the difference in light refraction

  • KandaPanda
    KandaPanda 15 hours ago

    Question: f'ing magnets.....how do they work?

  • Richard Nedbalek
    Richard Nedbalek 16 hours ago

    This video should have been sponsored by an eco-friendly laundry detergent manufacturer! 🤣

  • Suhrit Pradhan
    Suhrit Pradhan 16 hours ago

    So help me understand something.
    If I keep the bottle open for long time such that its pressure is equal to atmospheric pressure and then if I put a mentos in the drink, there would be no reaction right? Since the excess carbon has already left?

  • Roaminghomosapiens
    Roaminghomosapiens 17 hours ago

    That's a cockring

  • Michael Scharf
    Michael Scharf 18 hours ago

    At 7:34 you see a green layer on top but no red layer....

  • Michael Scharf
    Michael Scharf 18 hours ago

    The fly at 5:25 is funny

  • EllieTube
    EllieTube 18 hours ago

    who was not perplexed by any of this?

    RES KEN 19 hours ago

    KFC employees - "your order sir ?"
    Me - "a non equilibrium beverage"

  • Gemini Jake
    Gemini Jake 20 hours ago

    Boooo paper straws! Boooo! Lol

  • That Guy
    That Guy 20 hours ago

    Maybe start with a bottle that isn’t already shaken up that might help you understand.
    It is really common sense
    No need to try and figure something out that is easily understood if you just use your brain 🧠

  • URAsoreloser1
    URAsoreloser1 21 hour ago +1

    This validates my tendency to squeeze partially empty 2 liter soda bottles between pours. Less air space for the CO2 to escape and drink stays fizzy longer.

  • Henrik Larsen
    Henrik Larsen 21 hour ago

    So the ice cube experiences an underwater equivalent of chill factor (wind taking away warm surface air)?

  • Chris BigBad
    Chris BigBad 21 hour ago

    nice n all. but please don't go all king of random on us, will ya? I'd be missing the aerogel and stuff.

  • L D
    L D 22 hours ago

    Thanks !! As a kid we would shake cans until they exploded. So .... that is the exchange of gas as nucleation? 👀 👀

  • Skelassassin
    Skelassassin 22 hours ago

    What if you used salt water ice cubes? Would they the result be the same or different?

  • S S
    S S 22 hours ago

    That sound is soooooooo

  • Ab
    Ab Day ago +1

    Nicely explained, you make science fun (:

  • iBadger
    iBadger Day ago +1

    I think you can dip the paper straws in water, then put it in a carbonated drink. A soaked straw should have little to no air which would act as a nucleation site for the Carbon-di-oxide otherwise.

  • Divergent Droid
    Divergent Droid Day ago

    I have another TWO for you! I double Dare you to answer me because after you read this your mind will be Toast and I bet you Wont! In science Physics Laws Require Proof.. so much to the extent Nothing in physics can contradict these Laws without a physical demonstration in physics that proves the new claim.. thats the way it's taught to us all right.. . you with me so far.. good. Question 1) How can a Molten core of Earth produce Gravity when 1) a moving fluid has no defined mass and 2) any metal heated to molten levels Cannot produce a magnetism? and Question 2) How can there be a pressurized atmosphere next to a vacuum without a barrier separating the two where equilibrium fails to take place? That is Impossible and Breaks the second Law of Thermodynamics assuming the idea were real but of course it's silly. Both of those things Cannot be demonstrated in Physics. WE are Taught a Fantasy that does Not conform to the rules of physics as we know them. Earth Cannot be a spinning sphere in space.

  • Richard Jesch
    Richard Jesch Day ago

    New (possibly) perplexing problem. I thought this one out before hand and was elated to discover I was right. Here it is: You have a helium balloon in your car attached to the gear selector (or anywhere it is attached by a string and free to move forward or backward). Begin driving the car. During acceleration which direction does the balloon move relative to the car? What happens when you apply braking? Enjoy.

  • Jø Kərr
    Jø Kərr Day ago

    Paper straw? PAPER STRAW?!?! Am I the only one who has never seen, nor heard of a straw being made of paper? That seems like the worst material to make a straw out of. Either they are a west coast thing, or Florida (where I live) is behind the times, but I'm cool with that because as I said, paper seems like that last material you would want to use to siphon liquids.

  • nolastname
    nolastname Day ago

    Witchcraft !!!

  • Angus Shaw
    Angus Shaw Day ago

    Never seen a paper straw before tbh

  • Tessee
    Tessee Day ago

    Everyone knows if you ShAkE uP a CaRbOnAteD DRinCc

  • Azriel Jale
    Azriel Jale Day ago +1

    What kind of animal drinks his carbonated beverage with paper straw?
    Like....just drink with your mouth.

  • James Clark
    James Clark Day ago

    Physics of Dark matter

  • Leyzr
    Leyzr Day ago

    ...i enjoyed learning about all this stuff i will never use. well... maybe the ring one for a magic trick :P

  • ManTheTroika
    ManTheTroika Day ago

    When the salt is added to the fresh water the temperature changed to dissolve it. The explanation that the water from the ice doesn't sink because of density may be true, but is there more to this? Adding salt is used to change the freezing point and melt ice. To prove the rate is caused by the natural convection current in the fresh water, the experiment could be repeated using a laboratory stir rod in each cup to force roughly equivalent convection current. It would be interesting to do the experiment with all 4 cups at the same time, and see which is fastest and which is slowest. Could it be possible that the fastest and slowest would both be salt water?

  • mrnnhnz
    mrnnhnz Day ago

    the reason I like drinking fizzy drinks is that they're fizzy. So no, I've now got even less reason to hate paper straws - they make my drink more fizzy is good, and you can add that to the they're-better-for-the-environment reason too.

  • Rishabh Mutha
    Rishabh Mutha Day ago

    Can we make a sonic device that agitates the soda and generates nucleation sites? So basically a sound wave with enough freq and wavelength to agitate the soda.
    It would be so much fun to go around stores nucleating soda bottles without anyone ever knowing.

  • Mark Barton
    Mark Barton Day ago

    Upvote the fly! He is amazing!!!!!!!!!!!!!!!!!!!!!!

  • Kevin Wells
    Kevin Wells Day ago

    Just found you - through Smarter Everyday actually. Now I have two channels to keep my brain at least a little more active. Great video.

  • Martin Ninov
    Martin Ninov Day ago

    1 is silly, 3 is neat but boring, 2 is the only really interesting one...

  • Aenayus White
    Aenayus White Day ago

    convection is whats melting the ice the water is being replaced with warmer water thus starting a small cycle like a locomotive

  • Aenayus White
    Aenayus White Day ago

    omg did yall see that fly i wonder if it was watchin the ring fall real time n flew threw it just for the fun of it what are flys eyes natural fps?

  • ralph sampson
    ralph sampson Day ago

    So, does a paper straw make the beverage go "flat" quicker?

  • Przemyslaw Sliwinski

    When I take a dry ice and a germanium lens can I remotely freeze a glass of water?

  • raincandy3
    raincandy3 Day ago

    So why is salt used to melt ice on the road?

  • Tim Podhorn
    Tim Podhorn Day ago

    Very interesting...

  • Stacy Mackenzie
    Stacy Mackenzie Day ago

    I could give you a theory which may enlighten you while destroying any illusions you have about yourself and who you are. But screw that.

  • Micah Navarro
    Micah Navarro Day ago

    Why does homeboy remind me of less accent-y Elon Musk?

  • Daniel Fullington

    I thought the Mentos trick only worked on Diet Coke? Wouldn't nucleation on the surface of a Mentos be the same for any carbonated beverage?

  • Chip Chapley
    Chip Chapley Day ago

    btw, i only new the pressure didn't increase because the plastic doesn't explode from you shaking it........ why it doesn't increase is whats confusing to me though.... imma watch the rest and hope for a answer..

  • m090009
    m090009 Day ago

    5:29 omg did you see how fast was that fly and the aerial acrobatics that it did, it flew through the ring and diagonally. Maan that's awesome

  • Kero Kero
    Kero Kero Day ago

    Suggestion: Do a better explanation than "what-if" on: starting fire with moonlight

  • Eskaypi Amazing
    Eskaypi Amazing Day ago

    Also what about insulation