AntiChrist Posted November 10, 2020 Share Posted November 10, 2020 How big would a marshmallow have to be to crush a average adult from 1000 foot above? Link to comment Share on other sites More sharing options...
Moderator LogicalFallacy Posted November 10, 2020 Moderator Share Posted November 10, 2020 Well based on this calculator https://www.angio.net/personal/climb/speed.html At 1000 feet (304.8 meters) a 1 kg solid object would hit you at 77.29 meters per second. That would kill you - instantly. It would make a mess. However to crush you you'd need a larger surface area, and probably more weight. The average marshmallow is 2.54 cm across. Lets make it a square marshmallow for simplicity. The average weight is 7grams. Based on this a 1 meter x 1 meter x 2.5cm giant marshmallow square would be ((39.37 x 39.37 x 7))/1000 10.85kgs. I feel that something like that might do it? Not sure because we have to take density into account so it may not reach terminal velocity, and the hardness may not be enough to crush you. 1 Link to comment Share on other sites More sharing options...
disillusioned Posted November 10, 2020 Share Posted November 10, 2020 I don't think height has much to do with it. The density of marshmallow is about 0.5g/mL. The density of water is 1g/mL. Water drops literally fall on us from the clouds, and we're fine. Making it bigger wouldn't help either, I don't think. A large enough marshmallow would likely just separate around me if dropped from 1000 feet. In principle, if the depth was sufficient, I suppose I might find myself entombed in marshmallow, and then suffocate, but I don't see any way for me to be crushed outright shy of increasing the density. Mind you, I haven't actually run the numbers. 1 Link to comment Share on other sites More sharing options...
Moderator LogicalFallacy Posted November 10, 2020 Moderator Share Posted November 10, 2020 27 minutes ago, disillusioned said: Mind you, I haven't actually run the numbers. Run the numbers my man! Figure that density out and see if a giant marshmallow can kill us. (Re water falling from the sky - rain is fine. If you dropped enough water at once wouldn't that kill you - kind of like jumping from 1000 feet into the ocean will kill you? Link to comment Share on other sites More sharing options...
alreadyGone Posted November 10, 2020 Share Posted November 10, 2020 An African marshmallow, or a European? 1 Link to comment Share on other sites More sharing options...
disillusioned Posted November 10, 2020 Share Posted November 10, 2020 24 minutes ago, LogicalFallacy said: Run the numbers my man! Figure that density out and see if a giant marshmallow can kill us. I'll get on it and post back in a bit. 24 minutes ago, LogicalFallacy said: (Re water falling from the sky - rain is fine. If you dropped enough water at once wouldn't that kill you - kind of like jumping from 1000 feet into the ocean will kill you? Yes, but this has more to do with surface tension than density (this will likely be relevant in the marshmallow case too, no doubt). Its the same reason why a belly flop is painful while a dive isn't. If you dumped that much water from the sky, I think it would separate into drops on the way down, and we'd just get heavy rain. 1 Link to comment Share on other sites More sharing options...
Super Moderator TheRedneckProfessor Posted November 10, 2020 Super Moderator Share Posted November 10, 2020 I think it would also behoove us to determine whether we are talking about a true, Jet-Puffed style marshmallow or the tooth-breaker Lucky Charms style "marshmallow" pellets. Link to comment Share on other sites More sharing options...
disillusioned Posted November 10, 2020 Share Posted November 10, 2020 This a more complicated question than it seems. I've run a few calculations, but sadly there are some factors that I just don't know as I'll explain. Throughout this, I'm assuming a jet-puffed style marshmallow. Let's first consider the case where we're in a vacuum. A marshmallow dropped from 1000ft will have a velocity of ~77.3m/s at impact. The human body can withstand about 50psi applied suddenly. Assuming the marshmallow falls on my head, which has a circumference of ~24in, the force applied would need to be about 1020.4N. A collision time of 0.05s yields an acceleration of 1546m/s^2. Setting the force equal to the lethal value, we can find the marshmallow's mass to be ~0.66kg. At 0.5g/mL, this marshmallow would have a volume of 0.00132m^3, which corresponds roughly to either a sphere of diameter 5in or a cube of side length 4.5in. But here's one issue: marshmallows are highly compressible and don't have great structual integrity. A water drop of this size would break apart on impact with my head, and I'd be fine. I suspect that a marshmallow would deform/break in a somewhat similar way, and I'd be ok. Unfortunately I don't have the relevant mathematical information about marshmallows to actually calculate this. The bigger issue, though, is that I've assumed a vacuum. Taking the case of the spherical marshmallow above, and running a standard terminal velocity calculation, I get a value of about 12.45m/s, which is nowhere near enough to kill me. You would need to increase the mass significantly, which would increase the volume and cross-sectional area of the marshmallow to the point where it would be significantly larger than me. In that case, again, we would need to consider that the marshmallow is highly compressible and would likely break around me rather than crushing me. We would also need to consider that not all of the mass of the marshmallow would then come to bear on my head, as its boundaries would extend beyond my body on all sides. Therefore the effective force delivered to my body would be lessened. Bottom line: I don't think the danger would lie in being crushed on impact. I think the danger would lie in either suffocation or being crushed gradually if the marshmallow were sufficiently large. I can't really say for sure though. Having said all of that, I don't like marshmallows, and I should probably go do my actual job now. Link to comment Share on other sites More sharing options...
alreadyGone Posted November 10, 2020 Share Posted November 10, 2020 Does it matter if in the northern hemisphere or the southern? Link to comment Share on other sites More sharing options...
AntiChrist Posted November 12, 2020 Author Share Posted November 12, 2020 On 11/10/2020 at 11:31 PM, TheRedneckProfessor said: I think it would also behoove us to determine whether we are talking about a true, Jet-Puffed style marshmallow or the tooth-breaker Lucky Charms style "marshmallow" pellets. Not the lucky charm varieties. Link to comment Share on other sites More sharing options...
AntiChrist Posted November 12, 2020 Author Share Posted November 12, 2020 On 11/11/2020 at 1:29 AM, alreadyGone said: Does it matter if in the northern hemisphere or the southern? I have no idea. Link to comment Share on other sites More sharing options...
AntiChrist Posted November 12, 2020 Author Share Posted November 12, 2020 On 11/11/2020 at 12:21 AM, disillusioned said: This a more complicated question than it seems. I've run a few calculations, but sadly there are some factors that I just don't know as I'll explain. Throughout this, I'm assuming a jet-puffed style marshmallow. Let's first consider the case where we're in a vacuum. A marshmallow dropped from 1000ft will have a velocity of ~77.3m/s at impact. The human body can withstand about 50psi applied suddenly. Assuming the marshmallow falls on my head, which has a circumference of ~24in, the force applied would need to be about 1020.4N. A collision time of 0.05s yields an acceleration of 1546m/s^2. Setting the force equal to the lethal value, we can find the marshmallow's mass to be ~0.66kg. At 0.5g/mL, this marshmallow would have a volume of 0.00132m^3, which corresponds roughly to either a sphere of diameter 5in or a cube of side length 4.5in. But here's one issue: marshmallows are highly compressible and don't have great structual integrity. A water drop of this size would break apart on impact with my head, and I'd be fine. I suspect that a marshmallow would deform/break in a somewhat similar way, and I'd be ok. Unfortunately I don't have the relevant mathematical information about marshmallows to actually calculate this. The bigger issue, though, is that I've assumed a vacuum. Taking the case of the spherical marshmallow above, and running a standard terminal velocity calculation, I get a value of about 12.45m/s, which is nowhere near enough to kill me. You would need to increase the mass significantly, which would increase the volume and cross-sectional area of the marshmallow to the point where it would be significantly larger than me. In that case, again, we would need to consider that the marshmallow is highly compressible and would likely break around me rather than crushing me. We would also need to consider that not all of the mass of the marshmallow would then come to bear on my head, as its boundaries would extend beyond my body on all sides. Therefore the effective force delivered to my body would be lessened. Bottom line: I don't think the danger would lie in being crushed on impact. I think the danger would lie in either suffocation or being crushed gradually if the marshmallow were sufficiently large. I can't really say for sure though. Having said all of that, I don't like marshmallows, and I should probably go do my actual job now. Let's get the Myth Buster's on this one. Link to comment Share on other sites More sharing options...
AntiChrist Posted November 12, 2020 Author Share Posted November 12, 2020 On 11/10/2020 at 9:05 PM, alreadyGone said: An African marshmallow, or a European? Link to comment Share on other sites More sharing options...
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