[HN Gopher] 'Dancing' raisins - a simple kitchen experiment
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'Dancing' raisins - a simple kitchen experiment
Author : amichail
Score : 74 points
Date : 2024-09-02 20:10 UTC (2 days ago)
(HTM) web link (theconversation.com)
(TXT) w3m dump (theconversation.com)
| ricc wrote:
| This experiment always reminds me of Beakman's World because
| that's where I first learned of this. :-)
| eighthourblink wrote:
| What a memory unlocker this comment is - loved that show as a
| kid
| tantalor wrote:
| Don't miss this episode of Captain Disillusion with guest
| star.
|
| https://www.youtube.com/watch?v=sT_bTnkwLuE
| lagniappe wrote:
| Be still, my heart! I'm so glad PZ is still out there doing
| his thing
| cortesoft wrote:
| I must be a few years older than you... for me, it was Mr.
| Wizard's World that is stuck in my brain forever.
| 2Gkashmiri wrote:
| I wstched that show back in 2004 i think. For a year or so, i
| was hooked as a kid on.that show.
|
| Never again watched it but that was a big science jump for me.
|
| The thing is, i was a science kid from the start and discoverh
| and national geographic was amazing.
|
| I remember watching a show "is.it real?" When i was like 7-10,
| not sure but one episode was about stigmata. Just random.thing
| i remember.
|
| Then many years later, constantine movie i was watching on tv
| and i recognized the hand and said "thats stigmata".
|
| Stuff like that happens with me daily. I like.it
| eber wrote:
| It unearthed a memory of pee wee doing the raisins in club soda
| bit for me. (wow this show was nuts)
|
| https://youtu.be/SckzmAe2ACk?t=549
| ohwellhere wrote:
| My daughters have for years enjoyed dropping their plastic straws
| into their Jarritos bottle where it sits out of reach until the
| bubbles magically bring it back up.
| BobaFloutist wrote:
| Probably my favorite kitchen experiment has always been to put
| water and pepper into a small bowl, and then dip a toothpick with
| dish soap into the middle, causing all the pepper to instantly
| and dramatically scatter away from the toothpick.
|
| YMMV of course, but I always felt that it demonstrates something
| that's not all that visible and obvious otherwise - I feel like a
| lot of kid-friendly science experiments give an expected or
| intuitive result, whereas soap's weakening of intermolecular
| forces in such a dramatic and sudden fashion manages to connect
| the micro world with the macro world in a clearly visible, almost
| shocking way, while neatly demonstrating both why water is
| special and why soap is helpful.
|
| I dunno, I just always loved it.
| dylan604 wrote:
| I always enjoyed the corn starch liquid or solid test where the
| mixture behaves like a liquid while being stirred but behaves
| like a solid when sitting still.
| shagie wrote:
| Non-Newtonian fluids are fun... until they aren't.
|
| One time a group of college students I hung out with got a
| bulk order of silly putty. This was fun to play with. Until
| someone had the idea of dropping it from about 6 feet up onto
| the floor. It shattered. Picking up slivers of silly putty
| from the carpeted floor was not fun.
|
| Elsefluid ... a different category (shear thinning -
| https://en.wikipedia.org/wiki/Shear_thinning ) has it so that
| if you drop something through it, it takes {some time}. If
| you immediately drop another thing through it at the same
| spot, it takes {some less time}. One of the chemistry
| professors wanted to do some experiments with this type of
| fluid and had his grad students develop a proof of concept.
| There are some challenges with this - it can't be a thin
| cylinder of the fluid you drop it through since the distance
| to the walls is a variable in the speed too. It also needed
| to be a tall enough cylinder with enough viscosity that you
| could time it with a stopwatch (initially). One such fluid
| that has this property is ketchup. They bought 10 gallons of
| ketchup from the local grocery store (that's all that was on
| the shelf ... seriously, you need about 7x 20 oz bottles to
| make one gallon), poured it into a large cylinder... realized
| that they needed a clear bottom to see it, made a new
| cylinder with a plexiglass bottom, and did the experiment.
| They dropped steel ballbearings from height into the the
| ketchup and timed the duration it took to drop one and the
| same spot that another had just traveled through vs a new
| spot. It worked and so they then worked on synthesizing 40
| liters of a particular polymer that had that property
| (another significant effort - took much longer than buying 70
| bottles of ketchup) but had the advantage that you could see
| through it.
| jrockway wrote:
| > Picking up slivers of silly putty from the carpeted floor
| was not fun.
|
| One of my science teachers in high school told me about the
| time she got a chunk of sodium and a 50 gallon barrel of
| water. She threw the sodium into the water. It blew up as
| expected. But it also fragmented into a million pieces, and
| those pieces hit the dewy morning grass and also exploded,
| triggering a chain reaction. I think she said the students
| had to run around and stomp out a bunch of little sodium
| fires. That demo was not done the next year.
|
| > if you drop something through it, it takes {some time}
|
| This is totally unrelated to your story, but it reminds me
| of the demonstration where you take a strong magnet and
| drop it through a copper tube. It takes forever to reach
| the bottom (because the moving magnet induces a current in
| the copper pipe, which produces a magnetic field in the
| opposite direction). Honestly, it's probably the one
| science demo that blew my mind when I saw it. It's SO slow.
| And we had already learned about the math behind it, but
| was amazing to see in practice.
| shagie wrote:
| > Honestly, it's probably the one science demo that blew
| my mind when I saw it. It's SO slow. And we had already
| learned about the math behind it, but was amazing to see
| in practice.
|
| Many years ago (searching... Amazon 2017) got a fidget
| toy that did that... and digging around, its
| https://www.moondrop.space (It was $25 when I got it (for
| the set of three)... I wouldn't spend the current price
| on it).
| jihadjihad wrote:
| Agreed it is a great demonstration, and I remember doing a
| similar one with an aluminum foil boat as a kid. Make a boat
| out of foil, put it in water, then add a few drops of dish soap
| behind the boat and watch it "sail."
|
| The scientific name for this is the Marangoni effect [0].
|
| 0: https://en.wikipedia.org/wiki/Marangoni_effect
| JKCalhoun wrote:
| Weightlessness no doubt ruins a lot of the fun we have on Earth,
| no doubt adds a good deal more though.
| dctoedt wrote:
| The article doesn't mention the Dancing Raisins TV commercial for
| California raisins -- when I first saw it in 1986 I almost fell
| off the couch laughing. (But as Heinlein's Manny O'Kelly-Davis
| put it, it's a funny-once.)
|
| https://www.youtube.com/watch?v=pM2OK_JaJ9I
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