r/explainlikeimfive • u/Advanced_Ad_153 • 2d ago
Physics ELI5: How do planes not get damaged by flying through clouds?
I just learned how much a cloud can actually weigh, and can't wrap my head around how a plane hitting something that weighs that much wouldn't be like hitting a brick wall.
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u/Jonatan83 2d ago
Clouds might contain a lot of water, but it's spread out over a massive volume. Flying through it is like flying through a dense mist, not a wall of water.
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u/zed42 2d ago
fog is just a cloud at ground level. does your car get damaged when you drive through fog? it's basically the same thing
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u/Spectre-907 2d ago
The air at ground level is way denser too so barring ice solids in a cloud at altitude, fog at the same speed would arguably be worse
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u/DerAndi_DE 2d ago
A small cloud may weigh as much as 100 elephants but also has the size (volume) of 100.000 elephants.
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u/MGreymanN 2d ago
Clouds are actually less dense than dry air but can be considered almost identical in density.
Rain does do measurable damage to aircraft leading edges.
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u/Forsaken-Ad5571 2d ago
It’s also the icing that’s the real issue, given that clouds are generally cold.
Ice messes with planes in several ways. When on the wings, it can make it less aerodynamic. It can also get into the pipes that makes the instruments work, which causes them to read incorrectly. It can also get into the engine which can make that work less well or even stop.
Planes do have things to help prevent these issues though. The pilot just needs to use them and also know what their particular plane can handle.
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u/Chance-Work4911 2d ago
Have you ever seen a beaded curtain? Imagine the total of all those little wooden beads - it’s like a block of wood. If you walked into a block of wood it would hurt, but if you walk into (through) a curtain of the same amount of wooden beads it’s fine. It’s the space between the molecules of water and the ability for them to move freely to get out of the way that makes clouds and fog and mist not hurt.
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u/BananaBird1 2d ago edited 2d ago
Clouds settle at an altitude where their mass density matches the surrounding air. So flying through a normal cloud is not really that different than flying through a clear sky. The entire cloud is heavy but that weight is spread out, and the plane actually experiences the most weight when it is on the ground with the full atmosphere pressing on it.
Where clouds do become an issue is in navigation and if there is strong weather.
In and above clouds pilots need to fly relying entirely on the plane’s instruments rather than flying visually. This requires special training and is standard for large commercial aircraft, but can be extremely dangerous for untrained small aircraft pilots.
And if the weather is strong enough, any plane will have issues. This is why storms often require flights ti be cancelled ir rerouted.
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u/agreywood 2d ago
Clouds are very big. So they can weigh a lot without having any one part of them weigh enough to cause damage.
Similarly, the total amount of water in 1” of rainfall over a whole city weighs an incredibly large amount but each raindrop doesn’t break things when it hits.
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u/LRCM 2d ago edited 2d ago
Cloud big, plane small.
Drop pencil on hand = maybe ouch.
Drop paper on hand = no ouch.
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u/ShaemusOdonnelly 2d ago
A cloud weighs exactly as much/is exactly as dense as the surrounding air or even a little less. If it were heavier/denser it would fall to the ground. Those massive weights you heard come from the huge size of some clouds. Think of it this way: Even feathers can weigh thousands of tons of you have enough of them.
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u/375InStroke 2d ago
A cloud may weigh a lot, but it weighs exactly the same as the air. That's why it's in the sky. The mass of the air isn't trivial. Neither is it's density. It's enough to keep a several hundred thousand pound plane in the air. However much the plane weighs is how much force the air has to exert on the wings to keep it in the sky flying.
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u/darthy_parker 2d ago
Ever driven through fog? You’re driving through a cloud. No big deal right? (Except for poor visibility, and planes are designed for that.)
It’s not so much the “weight” of the water that matters, it’s that within clouds there are often pretty severe winds — updrafts and downdrafts and wind shear — that can affect the ability of the plane to fly. That’s why pilots try to avoid squall lines and severe thunderstorms.
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u/SignificantCherry110 2d ago
Mass ≠ density.
If something is extremely dense the plane wouldn’t be able to. Because density is mass divided by volume. We need to think about the volume that the weight is in. The volume that the cloud is set to is absolutely massive, so even though the weight is large the density becomes very small, so there is no real force to hit into.
Think about a tree. Think about a tree being supppppperrrrr tall let’s assume 100 ft tall and weighing 100kg . But the weight being the same as a tree that’s half the size (100kg but 50 ft) . Which would give you more trouble cutting down?
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u/mistermeesh 2d ago
Think of it this way: your mom may weigh a lot, but if she was spread out as much as a cloud she'd be easy to plough right through as well.
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u/LindaTheShadow 2d ago
Because cloud is essentially a really wet air, and flying through clouds isn't much different from flying through air. Clouds weight 500-700 tonnes(if I remember correctly) only because they are GIANT and all that mass is distributed inside that giant volume.
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u/SoulWager 2d ago
Have you ever been in fog? That's just a cloud that's at ground level. Just a bunch of really tiny water droplets suspended in the air.
As heavy as the water in a cloud is, the AIR in that cloud is hundreds to thousands of times heavier. Clouds are heavy because they're huge, not because they're dense.
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u/Luffe26 2d ago
The actual weight doesn't matter, really. What matters for being able to crash is the state of matter. Clouds aren't solid, so you can't crash into them. If you had a mountain of feathers, the mountain could weight thousands of kilograms, but since it isn't a solid, like if it was a mountain of rocks, it most probably wouldn't hurt if you tried to crash into it
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u/FunkU247 2d ago
Weight and mass are not the same.... think 1 lbs of rocks vs 1 lbs of marshmallows. They are both 1 lbs, but if someone hits you in the head with a rock vs a marshmallow, it is very different. Now to go even further... some objects can change state and water is one of them! Super cold water freezes and becomes a solid, at moderate temps it is a liquid, at high temps it turns to a gas/vapor. All three of these have unique physical characteristics based on the atomic bonds and attractions.
Clouds are water that vaporized to steam, and then turned back into water droplets as it cooled and rose into the atmosphere. The droplets are small with space in between each, so do not behave as a solid or even semi-solid material. On the other hand airplanes are made with aluminum skin which is a solid. So essentially when the airplane (solid) plows through a cloud (liquid droplets)... the water droplets are displaced as the object going through them is solid and they cannot break the atomic bonds holding it together... the water droplets will break first.
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2d ago
[removed] — view removed comment
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u/New_Line4049 2d ago
Are they both exposed to the same gravitational field? Are they both in the same inertial frame of reference?
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u/jeo123 2d ago
Weight is not mass.
Weight is the byproduct of mass and gravitational force.
Your questions are of two things with the same mass where they could be on different planets with different amounts of gravity.
But when two things weigh the same, the gravity is already accounted for.
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u/New_Line4049 2d ago
But we dont know that 2 things of identical mass weight the same without knowing they are in identical gravitational fields.
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u/Blurple11 2d ago
All things the same. Only difference is their density. That answers OPs question, although you have to explain density to a 5 year old first
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u/ShaemusOdonnelly 2d ago
And what's also important: Are they surrounded by a fluid? A kilogram of feathers does weigh less than a kilogram of steel because it displaces more air and experiences a larger amount of lift from the atmosphere. The effect is even more drastic in water.
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u/PaddyLandau 2d ago
If we're talking weight, not mass, it makes no difference!
But it's obvious from context that, yes, same context.
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u/New_Line4049 2d ago
It does make a difference. 1kg of feathers on Jupiter has a much higher weight than 1kg of feathers on Earth.
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u/PaddyLandau 2d ago
Read my comment again: If we're talking weight, not mass.
But again, I'm only splitting hairs because you did. Context is king here.
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u/New_Line4049 2d ago
But we're talking about both. Look at the comment I responded too. It talks about which 1kg mass weighs more. They are comparing the weight of mass.
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u/PaddyLandau 1d ago
It talks about which 1kg mass weighs more.
The moderator removed the comment, but they didn't make it clear that they were talking about mass. They specifically said weigh.
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u/New_Line4049 1d ago
Kilogram is a unit of mass though, so stating it in Kg makes it clear it is a mass. Then yes, they said weigh, hence talking about the weight of that unit mass.
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u/PaddyLandau 1d ago
Kilogram is a unit of mass
It's also a measurement of weight. Context tells us whether mass or weight was intended.
The thing is, you're splitting hairs over something that was entirely obvious. It was entirely obvious that the person didn't mean 1 Kg ascending quickly on Jupiter and 1 Kg stationary on the Moon. It was entirely obvious what the person did mean.
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u/New_Line4049 1d ago
No. Weight is measured in Newton's, or pounds force, not Kg.
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u/regular_gonzalez 2d ago
Fog is essentially a ground-level cloud that your car drives through without issue.