Bare Hand Bottle Busting- Science Investigation

You two guys are definitely Phineas and Ferb

When they both had different theories I was like oh no it’s like the two smart kids in class getting different answers

This never gets old watching it again.

Me after watching this video: “excuse me, friend, can I interest you in this delicious bottle of hot water?”

Imagine pulling out some kerosene snowballs during a snowball fight

Literally every time:
Mark Rober: High-Speed Projectiles!
Backyard Scientist: Set Everything on Fire!

From a fluid dynamics perspective:
It seems to me that hitting the top of the bottle sends a shockwave through the water. Shockwaves have extremely low pressure at the front of the shock and extremely high pressure at the back of the shock. When the front of the wave reaches the bottom of the bottle, that low pressure zone generated by the shockwave induces cavitation (the little pocket of vapor you see at the bottom of the bottle). The water cant hold onto the air bubbles that are already dissolved in it or stay in its liquid phase in this low pressure zone, similar to why boiling water is much easier at the top of a mountain; the atmospheric pressure is less. When the energy of the shockwave dissipates, this vapor bubble (cavitation) collapses...very, very, violently. Often times at supersonic speeds. The force of that vapor bubble collapsing at supersonic speeds (which brings the water crashing down onto the bottom of the bottle), is what breaks the bottle, in my opinion. Perhaps Schlieren imaging could confirm this.
It would follow that the CO2 bubbles in carbonation interrupt this shock wave from passing through the liquid, and keep the wave from reaching the bottom with enough energy to induce cavitation. The low pressure zone generated by the shockwave would cause the CO2 bubbles to escape from the liquid, causing the foaming in the beer you see
This phenomenon is very similar to the cavitation seen in boat propellers. The propeller spins through the water, generating a low pressure zone behind the blades of the propeller, and when this pressure is low enough, the water can no longer stay in it's liquid phase, releasing any dissolved gas and changing phase to water vapor, generating the vapor bubble you see behind the propeller. When the energy from the propeller dissipates, these vapor bubbles collapse at supersonic speeds, changing the phase back to liquid and dissolving any air/gases back into the water, but at the same time gouging a chunk of metal out of the propeller.
Edit: I've edited this post to clarify a few things, thanks to those who commented below!

"So as firm believers of science..." when you hear that

I totally think that Mark Rober, Backyard Scientist and the Slow-Mo guys need to make some of these videos together

Rubber mallet is a good idea. I can't tell you how many times I hurt my hand trying this.

I learned to do this forty plus years ago, while in college. I always did this the hard way, with coke bottles having thicker glass. Plus seeing why this works would have led to better results.

4:03 the moment when you are absolutely, and the absolute joy, these slomo cams brought a new dimension to science

Me: It's definitely just air pressure
mark: It's not air pressure
Me: It's not air pressure

Tried it at home.
Broke all the beer bottles in my fridge.
Now dad is beating me.
Thank you. *very* much...

I’ve watched this 3 times and KRplus just suggested it again so looks like I’m watching it for a 4th. I feel so much smarter and happier after just watching Mark’s videos

Yes! Glad you did this! I, too, thought it was the air pressure forcing the liquid down. I was taught in my teens (in the 80's) by a friend to use wine bottles! No wonder they worked so well being non-carbonated. Thankfully, only about 3 out of 50 have broken in my hand while attempting this.

5:22
Who the hell screams ”gonnorhea” when they hurt themselves

*The Slow-Mo Guys wants to know your location*

I seriously love these 2 guys! I could watch them all day

The fact that they have the "Corona Extra" Beer makes this even better xD

Funny how he uses a corona bottle for the water

"You should set those on fire"
Yes throwing fire balls at kids will be fun

I skipped the first part so all I heard was
“you should set those on fire”
But I only saw the kids so i was like
“Set ThE kiDS oN FiRE?”

I love your videos! You do such a good job on them!

5:12 "this is glass"
jerryrig : "glass is glass and glass can break"

2:52 Aww whos a good bottle? Pat pat*

Two things this video impress me is that
1. They came up really easy way to test their theory.
2. The slow-mo technology makes it so easy to prove the second theory.
That's such a amazing combination of big brains and technology.

The first I heard of this was in college, with Sobe bottles. My coworker bought a Sobe bottle so we could try it out. The story we heard was that you had to keep it sealed for it to work.
Hitting it gently, we could hear a loud cracking sound as the vacuum collapsed.
Hitting it harder it broke easily.
We tried with an opened bottle that was refilled. Cap on or off, it took a harder hit to get the cracking sound. My hand hurt too much to get it to break with the refilled bottle. I would love to see a test rig built to see the impact required for a sealed bottle vs an open bottle vs a refilled bottle with the cap on

how to mine glass in minecraft 2:53

*SET IT ON FIRE*
-Kevin (The Backyard Scientist) 2016

I’ve been waiting for this video for so long

Alright ima invite my friends over and give them a beer bottle with hot water it nail polish remover and hit the bottle. What kind of day is that

I love it when he shouts in pain Gonorrhea 5:22

3:55 Says they put red colour in The bottle to see The break easier.. shows clip of a bottle with a clear liquid

I really hope the two of you pair up, it will be the best thing that has ever happened

Your Videos are so interesting, my dad showed me one, a few weeks ago, and now my friend and me are so exited in watching your videos.
Ps. Sorry for my englisch😂 I am german

"I'm pretty bored today so I'm gonna smash bottles."

5. Don’t chicken out:
Shows mark hitting his hand and then mumbling ‘gonorrhoea!’.
Nice

Thank you for bringing me here Steve

I love it how he explains it so easily

5:23 I'm not convinced Mark didn't say "Gonorrhea" in a pained voice

BEST science channel on KRplus, I wish he would post more often

Theory #2 is the physics of a mean practical joke. When someone motions to "clink" your bottles together, instead of "clinking" the necks together, slam your bottle on top of their bottle and watch their beer spill on the floor lol

i needed answers n now ik thank you!!

did he say gonorrhea when he hit his hand on the bottle xD 5:21

I love how he’s talking about ready player one before the movie came out

I knew the explanation, but it's interesting to see it tested.

We do that with beers at parties. Not to break glasses, but to see people panicking, putting the bottle in their mouth trying to deal with the foam. Quite funny.

I wish he was my science teacher because he would be so fun

Mark Rober: has a corona beer in his hand
*intense breathing*

Yep. It's the Water-Hammer effect. The water and bottle are pulled together by the vacuum created from the initial strike. The water and bottle come together rapidly, and since water is in not compressible and has high mass, it's like hitting the glass with dense solid object and the glass shatters.

the shock from your hand travels through the bottle, and meets at the bottom center, as well as the water briefly lifts up(or if there is no liquid, its because of air pressure), and slams back into the glass, both those forces together make the bottle break, easy

I am using this for my science project thanks and I’ll put you as my source of information

He is Obviously the Fun Uncle

I've been drinking beer along time. Why did it take 5yrs for this to pop on my feed!

Congrats On 16 Million !! :)

I’m glad you used Corona bottles😂 fitting for this time

0:00
Those trees behind him looked like wings ._.

Who knew the scientific method could be such fun!

I love the backyard scientist and mark

0:28 Nowadays seems like Corona is takin its revenge, ain't it?

" just to be more consistent"
*also cause I'm a wuss
I was dying 😂😂 brush I would too

0:53
I’ll drink to that!
Not yet you won’t Kevin.
*BONK*
....
*hahaha*

still boys!
you get these great scientific minds together, this is the experiment they do. i chuckle.

05:24
That gave me the greatest nostalgia feeling I've ever had :3 So unexpected I wasn't prepared :o

Mark literally u are the best you tuber on KRplus keep up the good work

Mark: if you want to impress your friends…
Next day: all your friends come with beer bottles filled with water

With cap on, it is the vibration of forces exchanging positions like air changing with water force and bottle force with water. Also the bottom of the bottle Is heavier and more dense than the top area. Leads to gravitational pull

On the foaming of beer, I did a research project in chemistry at uni with my professor. And we found that not only do you find that bubbles are made, and then increased
because of a chain reaction, but this happens more so in beer than any
other drink! And that's because that beer is just crazy good at foaming because the bubbles are more stable, mostly due to the fact that the pH is higher in beer than cider, soft drink, and other carbonated drinks. The more you know!

Kid: *Throws snowball at another kid*
The other kid: AAHH IM ON FIREEE
Parents: ...

Slow motion cameras make experiments such as these soooo much more fun and you can actually get to the bottom of why it happens. Wonder if my iPhone slowmo will also show it? 😂

Does the amount of water you use matter? What about the type of bottle.

the *first* bottle they busted was a bottle of *corona* well, we got a lot coming, I can feel it

0:34
Mark: "...so either Kevin has some superpowers..."
Kevin: *nods*

Exulted compression of air in the bottle plus a downward force. Both of these combine to be greater than the force of molecules holding the bottle together. Leading to the air escaping some how... the bottom of the bottle. Plus force of gravity but that is sometimes negligible🤷🏾‍♂️

A college friend would always use his wine bottle and cheers people with beer bottles to get them to foam up. I noticed that if the level of carbonated beverage was below the shoulder of the bottle it did not effect it as much. I would love to see some high speed of this difference

You're definitely a nerd, a very cool nerd. I love every video and enjoy your explanations of science. Wishing you well and much success.

I can barely tell this video is from 2016. You've been incredibly consistent with it.

quick way to test the second round of theories would be to pull a vacuum in the bottle and see if it breaks

Maybe im missing something, but im irritated by "high vapor pressure works better".
The low pressure zone at the bottom is formed solely because of the liquids inertia, so shouldnt either
a) the vapor pressure of the liquid have basically no impact at all or more likely
b) a liquid with a high vapor pressure start to fill the low pressure zone with evaporated gas and cushion the liquid-hammer? (basically what you said 5 seconds earlier about the Carbonation?)

Oh my god! Ready player one is my favourite book ever!

How much beer did you drink during this

I love your content.

Question: deos this also work with soda bottles filled with water?

5:21 did he say “gonorrhea.”

That book seemed
Interesting.. You're actually making me debate if I should get the audible trial or not.. 🤔

Very cool trick!!! I tried it myself mind blown!!

Air don't need to be entered at the top cause hitting the top with force builds the pressure in cause a bottle isn't air tight anyways with a lid on. The bottle has some air init before opened, but the rubber hammer or the Parm of your hand must play a part init to stop the air escaping out the top once hit so the only way is down
My theory would be try hitting the hammer on the top without creating a seal, only hit the rim or the edge with all the same procedures as you did
Or try diffrent bottles or wider bottle necks with also my theory 🙂

that slow mo with the red bottle is so satisfying to hear

Conspiracy theory: they knew! they used Corona Beer Bottles!

As a glassblower and knowing a little bit about glass! The 90 degree angle on the bottom has a lot of stress compared to the rest of the bottle which is it's weakest point so the combination of things going on beyond my expertise. But I would use a polariscope to see how much stress is and where in the bottle it is. Bottles are made up of several coe's batched together. Which is another unstable make up of the bottle.

3:30 Without seeing the rest of the video I'd assume it's "water hammer" a.k.a. the volume of rapidly moving water hitting the bottom. And that movement is obviously caused by the vacuum. Similar mechanism is used during water forming to create curved surfaces out of metal for some cars.

Lol year's later and ready player one Is a movie I didn't even know they had a book 6:00

This channel gives me A+ at my science and chemistry tests than My teachers vids XD

Does it matter how much water is in the bottle? If it's actually momentum then it should break easier with more water. Alternatively, if it's mostly the cavitation then more water above the area of effect wouldn't do much; you just need a minimum amount so it forms a vacuum bubble and then collapses. I suspect it's more the latter and that extra water has little to no effect.

i think it's the pressuser the bottle is dealing with, it works with or without the water in it. the reason why it act diffrently to the carbon bubbles is beave it have more force than the glass reaction itself and that means the bubbles go mad and not the bottle doesn't

I have been watching your videos since the Halloween phone t-shirts (I bought one) it's awesome. Thank you so much for what you are doing, Keep up the good work bro 😉

Nobody:
Not a single soul:
Kevin: *YOU SHOULD SET THEM ON FIRE*

ive never had this happen when using a counter top to take off a bottle cap. is it possible that holding it at an angle kinda diffuses the force and causes the bottle not to break.

Wouldn't the liquids with high vapor pressure form more vapor (than liquids with low vapor pressure) at the vacuum and provide the cushioning effect just like carbonated liquids?