3 Perplexing Physics Problems

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Why does shaken soda explode? Does ice melt first in fresh or salt water?
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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); https://doi.org/10.1119/1.2343501

Agitation solution
The Physics Teacher 30, 325 (1992); https://doi.org/10.1119/1.2343556

Filmed by Cristian Carretero, Jordan Schnabel, Jonny Hyman, and Raquel Nuno

Music from https://epidemicsound.com “Seaweed” “Quietly Tense” “Mind Shift” “Observations”


Izzet Right? - Magic: the Gathering for Beginners says:

I've got a perplexing problem. Why isn't school this entertaining?

Isaac Paolino says:

This is a really long suggestion but, take a disposable water bottle with a screw on top that has a few layers of threads. Put a hole in the lid of the bottle that is the same width of a sports ball pin. Then fill the bottle about a quarter of the way up with ice, shake the bottle, then make sure the ice is over the needle in the bottle so cold air is pumped into the bottle. Pump up the bottle, with the lid on, to 50-60 PSI. Then remove the bottle and it should trap air for a couple of seconds. WHILE WEARING GLOVES, so it doesn't rip the skin off of your hand, remove the lid to the bottle and it should make a loud boom and go flying about 60-100 feet depending upon how much you pump up the bottle. Can you explain this phenomenon? (P.S. I have no clue how I discovered this.)

Nathanael James says:

Thermal camera on the 2nd problem might be better

oldcowbb says:

nice and classic veritasium video

Frank William says:

0:05 fake laughter to kick things off

quintary1 says:

if you look closely you can also see the line between the salt and fresh water

Liam Brown says:

But why did the ice cube in saltwater become clearer?

blake fosse says:

I hate to be "that guy" but the rough surface of the mentos is not the cause of its foaming, thats pretty easy to test by just using a different type of soda. Works better with diet coke than coke, and barely works with sprite.

Steven Crawford says:

So when we drop a bottle and feel it get harder, its just all in our head?

Archamus DK says:

so how do i keep my coca cola to keep its gas the longest?

fisherholmsfly says:

The fly, flying through the ring induced a slight voltage through the ring which caused the positively charged chain to be attracted to the Negative fly ions which resulted in the knot around the ring.

Robert Smith says:

Why does carbonated soda taste different?

Allen Petersen says:

Another excellent video. One question from our kids is "What is a nucleation site?"


So wait, If you drink a carbonated beverage while sitting in a chamber at 3 atmosphere… Would the pop taste flat?

Omar Esieed says:

Great video. Thank you

Zes says:

no such thing as entertx or or borx or not, do any nmw and any s ok

Marek Wojtowicz says:

I propose a qustion: What happens when you open the shaked up bottle really fast? I observed interesting results when trying that…

jaredt19 says:

I have an interesting sauna room riddle I came up with while in, you guessed it, sauna room: Take two identical 0.5L plastic bottles filled with tap water at say, 18°C, with you into a sauna room which is at around 100°C – one with cap on and the other one with cap off – which of the the two bottles will contain water at a higher temperature after half an hour in the room?

Karim Godoy says:

This guy just explained Decompression sickness, same happens while diving! That's why you ascend slowly from all dives!

eg says:

Hi Derek, what happens when a Mentos is added to the bottle of cola and capped straight away before the liquid can escape? Does the pressure reach 3atm quicker or does it exceed the 3atm?

DoctorX17 says:

Where the heck do you get paper straws?! I haven't seen those since the 50s

conmatt628 says:

Anybody noticed the fly on his finger at 5:26

Rafael Fernandez says:

The bubble. The bubble explodes

funkmastaflexxx says:

This is so entertaining

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