Forum: aviation.stackexchange.com
Tags: <cabin-pressure>
Title: Is it true that a soda can or a bag of chips will pop in a plane at high altitude?
Question: I've heard some conspiracy theorists claim that if you were to bring a soda can or a bad of chips onto an airplane, they would pop?   Is this true? If so, why?

Answers:
sents: text: Not likely.
text: Consider how food products normally make it to you.
text: Any competent US maker of soda or chips will design their product to be shipped on Interstate 70 or 80, via Sherman Summit (8650') or the Eisenhower Tunnel (11,158') or more likely by rail , via again Sherman Summit (8015') or Moffat Tunnel (9239').
text: *
text: Aircraft are pressurized to a pressure altitude of 8000'
text: typically, so Sherman Summit (rail).
text: If a food manufacturer were to botch their packaging, they wouldn't have your problem of a soda can bursting, they'd have an entire container load of sodas or chips burst and ruined for sale.
text: That is simply unacceptable, so manufacturers have a big incentive to get this right.
text: Other markets will have similar issues - the EU has the Alps, and China and India have the Himalaya.
text: It does not apply to regional sellers in flatland areas, so
text: a regional/indie Florida chipmaker, all bets are off.
text: It does, however, apply to soda manufacturers, whose cans must endure extreme temperature (e.g. solar loads in a car) also in high places.
text: *
text: Tennessee Pass (10221') doesn't count, it is weedgrown, rusty and cut in several places, being held for future capacity needs.
answer_details: author: aviation.stackexchange.com/users/22864/Harper - Reinstate Monica
score: 28
sents: text: I can confirm that bagged snacks can pop from the pressure difference.
text: Climbing through 7,000 feet (on our way up to 9,000) in an unpressurized PA32
text: we heard a quite loud POP.
text: In and out of clouds at the time we were busy in the front seat, didn't observe any flight control or systems issues.
text: Fortunately had a person in the back that looked around there for us.
text: After trying to look outside at airplane surfaces for awhile
text: she turned her attention inside and found a bag of popcorn (the already popped, snack style) had exploded...
answer_details: author: aviation.stackexchange.com/users/49/Brian Knoblauch
score: 12
sents: text: I brought a bag of chips on a Quantas A380 flight recently and it ruptured during ascent.
text: Sitting very close to the bag, I thought the sound was quite loud.
text: Nobody else noticed it.
text: Results may vary from bag to bag.
text: Chip bags are pressurised relative to the atmosphere.
text: As the plane climbs, the pressure in the cabin drops, which increases the pressure difference.
text: This pressure difference may exceed the strength of the bag, causing it to break.
answer_details: author: aviation.stackexchange.com/users/20174/Anonymous Physicist
score: 5
sents: text: Soda cans are designed to withstand much larger amounts of pressure from the inside.
text: Ever tried to squeeze a soda can that has just been shaken?
text: Taking away outside pressure can only increase the inside pressure by 1atm - and that would mean placing the can in a vacuum.
text: Simply shaking a can will increase the inside pressure much more than that and a can is supposed to survive even more than just shaking.
text: You can make a soda can burst by heating it up, but that'll require quite a bit of heat.
text: Bags of chips are not designed to withstand large amounts of inside pressure because chips to not generate any pressure like a carbonated liquid does.
text: Depending on the pressure at the time of packaging and the packaging itself, they usually do "inflate" a bit on a flying aircraft and in rare circumstances they may even burst.
text: [edit]I decided to dig out some numbers, so here we go: https://hypertextbook.com/facts/2000/SeemaMeraj.shtml
text: A cooled soda can have an internal pressure as low as 1atm (~100kPa) up to more than 2atm.
text: At room temperature this goes up to around 4atm.
text: So taking a can out of the refrigerator and putting it on the table increases the pressure more than placing a (cooled) can inside a vacuum .
text: As has been pointed out in the comment, shaking may not significantly increase pressure.
text: (I was expecting a more than minor increase because a bottle that has recently been shaken certainly feels "harder", but OTOH you need to be really careful when it comes to "feeling" things like pressure!)
text: Temperature, however, does increase pressure significantly and I would expect a soda can to be designed to withstand the pressure of a hot summer day in the shade - i.e. 40°C/100°F.
text: (It's not trivial to predict the pressure at that temperature, so I'm not trying.)[/edit]
answer_details: author: aviation.stackexchange.com/users/15980/Thomas
score: 3
sents: text: I have never had a bag of chips pop in a commercial flight (although I've had bags that seemed to be right on the verge).
text: On the other hand, in a single engine non pressurized Beechcraft Bonanza we had a bag of chips explode in the cabin as we were climbing to our cruising altitude.
text: It's been too long for me to remember our altitude, but it can and does happen.
text: Scared the crap out of me as it was near me when it happened and
text: it was quite loud.
text: Can of soda?
text: Haven't had one explode in the air.
text: I have had cans of soda explode due to heat though in the summer in the trunk of my car, on several occasions.
text: Luckily in my case they were all seltzer water.
answer_details: author: aviation.stackexchange.com/users/33186/xcr
score: 2
sents: text: The only reason it might pop is if the cabin pressure were to suddenly disappear.
text: That's explosive decompression and if it happens you've more serious problems than having some soda or crisps soil your clothes or whatever is in the bag it popped in.
text: I did once get the advise to open any cans or bottles containing carbonated drinks I was planning to consume during a flight before takeoff, but that was on board an old Soviet era aircraft with a faulty pressure cabin.
text: In such cases the sudden release of pressure can cause the liquid to spill out, similar to shaking a bottle of soda violently before opening the lid would do on the ground (or, as my aunt once did mistakenly, freeze cans of soda so they'd be nice and cold for next day's road trip, then leaving them out in a hot car where they built up so much pressure they ruptured).
answer_details: author: aviation.stackexchange.com/users/900/jwenting
score: 1
sents: text: Definitely.
text: I have seen it on older aircraft at medium altitude chips bags can pop easily.
text: Altitude at which no cabin pressure is even required.
answer_details: author: aviation.stackexchange.com/users/33170/user3481141
score: 1

Summary of the answers:
There is debate as to whether a can of soda or packet of chips will pop at high altitude. Some observers claim it has happened while others do not think it is likely to happen.
Some support that chip bags can definitely pop on a high altitude and that they have seen it happening. However, some support that an explosion of this type is not possible and they have never seen it happening. On the other hand, some others say that this phenomenon is quite rare, but it could happen depending on the pressure standards while packaging. Finally, there is the view that if the cabin pressure could totally disappear, only then cans and bags could pop, that is an impossibility.