Question/challenge how high can you send a candy bar before the wrapper breaks?

or what sort of altitude would it take to unwrap a candy bar? take a 1.94 oz. 3musketeers bar for example, would the wrapper survive intact at 10k or would you need to send it higher (inside the airframe to protect it from airblast and heating)?
Rex

Great question! But I have a crappy answer... who knows.

I work at a company which handles product for a large salty snack company. I'm almost sea level. I understand that they put less air in their bags when they are destined for cities over the mountains of SoCal (because the bags expand in the high desert or the "real" mountains of NV, UT or CO).

thought it might be a fun challenge, plus there is the bonus of a quick snack for the walk back from finding the rocket . what got me thinking, was I launched 4 oz. of M&M's today...then we ate the payload afterward .
Rex

Wouldn't poking the motor in it and gluing the fins on be a problem?

Recovery system? Why bother? Let one outta yer sight for a minute and someone else gets it, anyway.

I've noticed the Hershey bar has about zero air , but, the answer is a hard one. Sometimes wrapper strength feels like the result of a reverse engineering project working with UFO skin. Now, increase the internal pressure. When would it pop? IF the rupture pressure exceeds the compression the candy can withstand, you're getting a smaller candy bar back, wearing an oversize suit.

First test would be to put the candy bar into a vacuum chamber and depressurize it until it fails.

It's possible that it might not rupture all the way to full vacuum. Some of those wrappers are pretty tough.

Knoshing on a candy bar after a flight might not be the best choice depending on location (melting notwithstanding). My OFFl rocket's nose weight was a 16oz. can of Diet Coke. Unfortunately for me, by the time I actually managed to launch it, and recover it intact for my L1 certification, the soda was warm. It was suggested that I should have used beer, but as I can't stand beer, I'd have needed to settle for an A&W, or Barq's. However, a candy bar, or too sweet of a soda, in a dry environment, and I'd only end up thirstier.

Hypothesis: There is a large variation from one factory batch to the next, even for one product. I would, of course, have to do several flights using bars with varying date codes in order to test this.

Second, independent hypothesis: the most common failure would be a small opening in one end, not a significant rupture. That is, it would not pop, but rather spring a small, undramatic leak. Once again, since this is a matter of the relative frequencies of two competing failure modes, I would have to do many flights to test it.

I have no idea how high you need to send a candy bar to get the wrapper to pop.

I do, however, know that putting a Tupperware container of spaghetti sauce in an ice chest and then driving up over the Sierras will spread sauce all over the inside of the ice chest.

Kind of spoils the idea of having spaghetti for dinner one night at the launch.

I just got my vacuum chamber up and running, I'll throw a 3-musketeers bar in there in the next week or so and tell you/film the results. I'll put a stratologger in there as well for a nice altitude curve.

considering how hard some of those wrappers are to open, I will hazard a guess of 50k or better .
Rex

I've brought a bag of chips onto a plane, and the bag does puff up / balloon nicely. I'd be curious as to the consistency of the 3 musketeer's bar too, being a foamy nougat interior. I understand marshmallows puff up nicely in a vacuum too..

dr wogz said:

I understand marshmallows puff up nicely in a vacuum too..

Click to expand...

Can confirm, the air is then pulled from the marshmallow so it shrivels up on the return to normal air. They also taste rather poor afterwards, though that might have been from a misting of vacuum pump oil...

We used to vacation in Aspen and I found it interesting to go in a store and see all of the wrapped products fully inflated. It was actually somewhat difficult for them to keep some items stacked properly. I can't imagine that the vendors custom pressurized their products for dozens of different altitudes and probably only had one or two pressures for their delivery locals.

Taking a bag or Doritos from sea level over the Sierras, it blew out somewhere near the Tioga Pass at 10,000 feet. It was so loud I thought something on my truck had exploded until I smelled the nacho cheese.

Aim for 10,000 feet. Try lots of different candy bars and maybe small bags of chips. You may not be curing cancer, but it doesn't mean it's not a noble cause. Or at least a fun one.

I would tend to believe that it is an overlooked area of study, doubt that nasa has put much effort into studying the effects of low pressure on food wrappers. we might even get a jump on them , after all, think of the fuel savings if you don't have to maintain a pressurized cargo pod.
Rex

If this works out you'll have the best smelling parachute in the rocketry world.

My problem is the snack food would never make it to the rocket.

<burp>

Yeah, chocolate bars & bags of Doritoes seem to be more akin to "recovery crew fuel" or "spectater snax" than "payload"

But to be able to say: "This candy bar (munch munch munch) went to (munch munch munch) 10,000ft at mach (munch munch munch) .85 (munch munch).. tastes pretty (munch munch) good!" would be worth it!

I Don't understand how it works in rocket's that the bar would blow up like a balloon. I have built many home built ex plans and if you don't vent the wing between the ribs the wing skin will try to implode. Please help me understand why it will balloon rather the be like a vacuum bag.

if there is air in the bag then as the altitude increases the air pressure outside the bag decreases. Thus, the bag will expand because there is less air pressure trying keep the bag compressed.

Why does a high altitude balloon get smaller as it gets higher then? Does it not have air in it? Or is it the gas they might use to keep it from getting bigger?

Weather balloons actually expand as they rise and the atmospheric pressure decreases. They eventually burst and the payload drops back down to Earth.

https://science.howstuffworks.com/n...eteorological-instruments/weather-balloon.htm

The decreased air pressure at higher altitudes is also why we drill vent holes our body tubes. If we don't and the rocket ascends fast enough, the internal pressure could cause an early separation, deploying recovery while the rocket is still on its way up.

Always good to learn.

May I suggest you put a snack treat in your next rocket and enjoy the delicious experiment results?

I get the feeling if I tried this, the experiment notebook would be pages of "experiment failed, continuing research" with a lot of chocolate and/or cheesy fingerprints.

We keep M&M packs in our unpressurized cargo compartment up to 45,000 feet and they don't explode. Bags of potato chips do and sometimes Kashi bar bags do as well. Keurig k-cups will burst as well.

M&M wrappers are more paper than an air tight plastic wrapper, at least the ones here are.. Chips have extra air in the bag for padding, and do puff out quite nicely..

if you look, you'll find the odd video of a near earth orbit balloon at moment of bursting quite neat actually..

I've also been told to remove my bass (the instrument, not the fish) strings if I fly, as the strings would explode at altitude. Of course, I've never flown my bass (nor to I play one anymore).. But I must say, I do have a hard time believing that one..

The kashi bar wrappers are very similar to candy wrappers like butterfinger and snickers.

Im guessing about 42 inches before I break it...mmmmmchocolate!

who'd take the risk of loosing it and why????

Alrighty, I have collected the evidence and have some results.

I'll post the videos and photos in a day or so after I find my stratologger cable.

What about a coupla air bubbles from packing material?
Some aren't round, they're like air filled miniature pillows. And they are tight, on the ground.

sounds like there was something to see, should be interesting. wonder what the candy looked like after the vacuum(and before the tasting )?
Rex