Will a Drone Be Pushed Backwards Inside an Accelerating Truck?

[@TheActionLab]

Sorry I didn’t put a reference. The front of the truck is to the right side. The back is to the left. Did you guess right? Also, you can download Opera for free here: opr.as/Opera-browser-theactionlab

[@lgl_137noname6]

So, what happens to the drone with back of the truck open ?

[@michaelmachiavelli]

Too bad you can't do an experiment where the back of the truck is a vacuum. Without the fluid of the air keeping the object in place if I remember correctly they would fly backwards. Of course it's been awhile since I took a physics course, I could be wrong lol 😆

[@maozedong8370]

Okay, how come in the elevator test you did with the drone, it DID hit the bottom and the top when the elevator moved? Why is it different for the elevator?

[@FedeG86]

Yes, I did and I'm using Opera browser since 2019 in my phone. 😊

[@bigsiege7684]

The linear velocity of the earth is 465 m/s. If the drone stays in place in the air and the ground does not move beneath it, then it is logical to assume that the same will happen in the truck. But things turned out to be more complicated.

[@sethdhanson]

For anyone confused about the difference between this and the Smarter Every Day demo: Destin’s balloon was tied down, not weighted. Therefore the balloon itself had less mass than the air and was pushed forward for the same reason it floats upward. The balloon in this video didn’t float up because it had the perfect mass attached to make it perfectly buoyant in the air of the truck, and that’s also why it doesn’t move horizontally.

[@johnnyragadoo2414]

Notice that it tended to sink as the air developed a slight horizontal gradient. That’s my theory, anyway.

[@LTVoyager]

Yes, it is all about density of the object versus the liquid surrounding it. A heavy ball on the floor will roll backwards since it is more dense than the air. A neutrally buoyant object doesn’t move as the sees the same force as the object. A less dense object, such as a tethered balloon will move forward since the force on the air moving it back is greater than that on the less dense object.

[@tw6896]

Correct. To see how a dense object behaves, all you have to do is peak inside the UPS truck on your next delivery and look at all of the thrown about beat up packages. HaHa!

[@larrybremer4930]

Liquids and Gasses are both Fluids and a Helium Balloon is a fantastic pressure gradient discriminator. Even with the slightest of pressure gradients it will move in the direction of the lower pressure which is what makes it rise in our atmosphere until the air is thin enough that its mass is equal to the sum of the mass of the helium, the balloon, and any other mass that is attached. This is why a floating balloon is said to be "lighter than air". Since its neutrally buoyant in the vertical axis it can reach an equilibrium where it the same mass as the air mass around it at the same volume, however once the truck begins to move there will be a gradient created in the horizontal axis that has not been quenched by mass tuning neutrality. This is because the air is a fluid and it is being slightly moved around as the truck changes velocity. When the truck accelerates the air in the box will be motionless for the same reason we get pushed back in our car seat. The truck has to accelerate that air mass but what will happen first is a kind of pile up in the back. Because air is compressible the air in the back will become denser (higher pressure) during the trucks acceleration and less dense toward the front of the truck. Once the truck stops accelerating (but can still be moving) everything will again reach the same equilibrium whether the truck is moving or stationary. The effect is only see when an acceleration (change of velocity) is applied. The problem with the truck though is that it cannot accelerate hard enough to see the effect due to it being mass tuned rather than tied down. If the truck was able to accelerate hard it would be able to interact with the difference in density in the truck box air. It would however only move a nearly imperceptible amount without extreme changes in velocity creating a significant pressure gradient. The drone would behave the same way if it could ever be in a stable flight configuration without some kind of active control but any helicopter is inherently unstable thus it is a bad test subject here.

[@willemm9356]

Also note that the balloon rotated under acceleration.

[@Zappy1210]

I figured this science out when I was 16 in a friends car. He was pulled over for speeding (50 in a 30). The cop asked him why he was speeding. Friend: "I was trying to outrun a bee that was in the car." Cop: "You're an idiot, here's your ticket".

[@pepsiCola-e9p]

that friend is definitely the class clown

[@thawzinkhant1759]

😂😂

[@jrseitz21]

I saw that tv show episode too

[@Not_PretendingTV]

Hahaha😂

[@tomanporc3721]

Ah yes the friend I see wink wink

[@carlveilleux5744]

Another interesting phenomena happens in small passenger aircrafts, especially those with long and narrow fuselages like a CRJ900 or Dash8-400. This is more obvious during winter. When passengers board the aircraft, the door at the front is open. Cold air from outside enters the cabin, but there is a heating system (external or APU) that pumps hot air in the cabin at the same time. This results in a layer of cold air near the floor, especially at the front of the aircraft, and some warmer air near the ceiling. Basically, the warmer air floats on top of the colder, denser air, and gravity is the only acceleration felt, straight down. The interesting thing happens during take-off: as the aircraft accelerate, a rearward component is added to the acceleration vector, so the cold dense air starts moving towards the rear of the aircraft, while the hot layer on top of it keeps floating and gets pushed forward. If you're sitting at the rear of the aircraft, as the acceleration pins you on your seat, you can actually feel a sudden rush of cold air, especially at your feet, it's an actual cold wind down there, and you can really feel the cold. Those in the front rows feel the opposite, it gets super warm all of a sudden (very noticeable since they were the ones partially exposed to the outside cold during boarding!). If the aircraft was climbing vertically, all the cold air would be at the rear and to how air at the front! After a moment the aircraft speed stabilizes and cabin temperature eventually equalizes. But this is a very noticeable phenomena.

[@Just_Joshing024]

You know, that's really cool. Thanks for sharing!

[@racerx250]

My feet always freeze on smaller planes no matter where I'm seated onboard.

[@stuntpenguin]

on long flights in widebody aircraft at high altitude there's also an appreciable difference in air temp between front and back - the front of the plane is pitched up and the warmer air will tend to collect there, so I like to head back to rows 40-46 on a 777 where it's much cooler.

[@Friek555]

@@stuntpenguin Why is the plane pitched up during the flight?

[@fresh_dood]

Wow you just helped me understand a related phenomenon in an ambulance potentially. I always wondered why it felt warmer when we started getting up to speed in the front of the ambulance. There's a pass through window from the rear to the front, and the back "box" has a lot of volume and probably enough warm air to make a difference if it's shunted to the front.

[@SuzukiKid400]

Dangling a plumb Bob from the ceiling of the truck would have created a good visual indicator to the audience of when the truck was accelerating and in which direction. Otherswise, great video.

[@gircakes2]

The truck is now a controllable sim.

[@RomanSangemino]

I've been posing this question to people for YEARS, without looking for an explanation! Thank you for this video!

[@TheTyisawesome]

Lol after filming that fish clip, "Uh actually I decided I don't want a fish"

[@my3dviews]

Not even for dinner? 🤔 😂

[@fluffsquirrel]

*shakes fish* Fish looks fine "I don't like this one"

[@junkiejackflash]

I was thinking the same thing when I saw that

[@nopel.]

😂

[@TheTyisawesome]

@@fluffsquirrel lol😂

[@vinaybharadwaj4688]

bro you literally clear every single doubt that pops in my brain without me even asking for it. Thanks man

[@acuddlyheadcrab]

fluid dynamics needs a spotlight in education

[@alsto8298]

@@acuddlyheadcrab *US education. Not education in general. Also, there are a lot of other problems like limits, units, etc. that ain't the case in other countries.

[@hummuseater44]

@@alsto8298 what the hell are you talking about man

[@itskittyme]

@@hummuseater44 dogs and cats

[@alsto8298]

​@@hummuseater44 That video bears no surprise (except for blogger stupidity and misunderstanding of basic concepts) for those who finished school in 2nd world countries (CIS basically). So what I mean is: fluid dynamic needs a spotlight in US education, not education in general because it is a local education problem. Same as many others there. If you want a proper education, you either pay handsomely for private school or change the country.

[@dobacetr]

It is wrong to say that balloon or fish does not move. They do during acceleration, however it is miniscule. The air inside the truck does experiences a pressure gradient during acceleration, the air does move backward as well. However, it is small. The dominant effect is inertia to friction ratio. Drone has bigger ratio, which means it moves more while balloon has even more friction(bigger surface) while it is lighter(presumably). You may want to get a balloon as heavy as the drone (with similar effective surface area) to confirm your theory about density. This also explains the motion of the fish. Water bring you to a stop almost immediately if you are not fighting back.

[@ralfp8844]

More accurate, yes. But your explanation supports his claims. The pressure gradient is the reason, why a floater less dense is accelerated less forward (outside perspective), so it seems to move forward (inside perspective). So my guess, density matters a lot here. The moment the resulting forces of pressure differences are high compared to others the effects out of it matter. The drone instead isn't that sensitive to pressure gradients but to the movement of the surrounding air at a whole. It's like a wind that pushes it aside. The drone withstands that push due to it's mass but if the wind continues it eventually will float in exactly the same speed. At least that's what i think.

[@JayH-r4y]

Correct, you can clearly see the weight at the bottom of the balloon move toward the rear of the truck because it has more mass than the air around it. The balloon just doesn't have enough mass to overcome the air. In fact the air moves a tiny amount too but, being air, in a container it expands and pushes itself to fill the box making it go along with the truck.

[@xonx209]

In other words, the air inside will temporarily compresses towards the back due to inertia. However due to the truck being driven too slowly, this effect is not noticeable. Otherwise the balloon should move towards the back and then bounce back forward. Maybe try this on an airplane during takeoff or landing?

[@ezwtwrziehag1736]

u dont get it ..

[@drmuffin8403]

The effect would be the same if there was no friction. When considering an accelerating vehicle, you can just think of the acceleration of the vehicle and gravity adding up to make a single acceleration pointed diagonaly. The main difference between the drone and the baloon is that the force maintaining the drone in the air depends on electricity supply which doesn't increase with acceleration and is directed by the drone orientation so only the sideways acceleration isn't canceled whereas the balloon has its force tied to Archimedes' priciple so as the acceleration increases the weight of the air increases (W=m*a), the force keeping the baloon from falling increases and cancels its inertia. In constantly accelerating condition, the drone would require tilt and extra power to remain in place but the baloon wouldn't move.

[@DrSlipperyFist]

Acceleration will cause your position inside an object to change. Constant velocity won't. When the plane is taking off, you feel pressed into your seat because of acceleration. You are free to walk around the cabin, even as the plane moves at 600 MPH, because the speed is constant and not changing.

[@some-replies]

Everyone should know this. Does the drink go flying out of your cup when you're driving 60 mph?

[@sm5574]

0:12 That fish is so confused!

[@PrincipalAudio]

Quick tip: You broke the 180 filming rule, which means you were filming things from angles greater than 180 degrees difference and comparing the two side-by-side. Truck moves left (forward). Drone moves left (to the "back" of the truck). Just a hint for future videos so they come across more concisely. Hope it helps. Love your videos. :)

[@Jorbey]

@Nats_termiteshe made all that up

[@RyanWehner-f2h]

​@Nats_termites he clearly states what 180 meant in the same sentance 😂😂 I only laugh cuz I kinddaaa almost not really read it the same way lol

[@dontwanadisplaynameonutube2951]

By necessity you need to break the 180 filming rule for my c**k.

[@kylespevak6781]

​@@JorbeyNo, it's a rule in film making to make things more easily understandable, usually dialogue

[@OneWildTurkey]

An easier way to say it is 'don't change your orientation' or 'be consistent'.

[@expertIsNotGaming]

This is a certified mythbusting classic...

[@Supremax67]

Now do that experiment with a bowling ball and dare say it won't move. It's all about containment pressure vs density of the object.

[@ASDasdSDsadASD-nc7lf]

@@Supremax67 Obviously, but why didn't you make a point?

[@Supremax67]

@@ASDasdSDsadASD-nc7lf -- I did. I guess obvious comments are too obvious?

[@BlueBanana-ug6dp]

​@@Supremax67Inertia moment

[@wesleeysutton5935]

You dident get the point of this thr bowling ball is touching the truck how could you make the ball float ​@@Supremax67

[@Sonnell]

Nice but 2 thoughts: a point of reference should have been added. Like a ball, which would have rolled away when accelerating or braking. Also, would have been nice to see the drone with open doors, or everything with an open platform, like on a pickup. Science communication channels nowadays always just show the effect, but they miss showing the other aspects, cases of it, for comparision.

[@LeSkateWA]

Some good ideas there in hindsight

[@irakyl]

When I saw the thumbnail I was really curious to see what would happen when a drone that flew alongside the truck entered it from the open back

[@BadL_]

Only in a fully enclosed space is this possible or even worth doing. In the back of a pickup or just out in the open on a platform is useless, there are ZERO forces that would be effecting it. Imagine what would happen if you were floating in the air above a vehicle. Nothing would happen once it moves because you are in no way connected to the car

[@joemency2242]

​@BadL_ which is why it would be interesting to show exactly how each of those scenarios affect the drone and balloon. Im sure most people didn't expect there to be almost no motion for the balloon in this experiment

[@MrMoo272]

This is the first video i've watched of yours that i actually got everything. My scuba diving course taught me all about boyancy and when you're neutrally boyant (which you should be most of the time), you move with the water and the fish and the coral all move back and forth at the same time, you can see it when you watch videos of the neutral buoyancy training but its so surreal when you're actually down there, everything has a kind of rhythm, all moving together.

[@masscreationbroadcasts]

2:30 Why are you a psychopath that puts the back of the truck on the left side of the screen?

[@TheBanjoShowOfficial]

This shit had me confused initially

[@dantetre]

Left to right rule. Smaller, past things on the left and bigger, future things on the right. -Writing (Western cultures) -Number scale -Time scale -Video player Are you left handed?

[@kevindevlieger300]

2:52 Slight suggestion for the visuals. The truck is driving to the left so I assumed the drone was going forwards. What kind of sorcery is this? 😛 If you'd mirrored the vid of the truck it would go in the same direction and make it less confusing.

[@Qwarzz]

Yea it was a bit surprising. Camera needed to be at the other wall or atleast could have marked the direction to the front.

[@chitlitlah]

Or just put an arrow pointing to the front of the truck before acceleration. I was confused too since he kept switching which side the camera was on.

[@deloeste33]

It also confused me because all the other shots point in the opposite direction, in an interior space with no defined features or objects or shadows that clearly indicate which is the front of the truck.

[@charlottelanvin7095]

0:08 there's an arrow telling you which way is back. all the animations of the moving truck are consistent with this. what is so hard to understand?

[@kevindevlieger300]

@@charlottelanvin7095 its not hard to understand. Its just that the videos arent matching. 😅

[@lavishsharma6049]

Now put your biggest vaccum chamber in the truck

[@davidmelies8549]

No point, can't fly in a vacuum.

[@trucid2]

A rocket drone in vacuum.

[@lavishsharma6049]

Yeah. Right

[@person8064]

​@@trucid2 the exhaust would make it not a vacuum

[@JustAnotherCommenter]

Next, put your truck inside your biggest vacuum chamber

[@excrubulent]

I think you're missing one detail about how the wind alters the movement of the drone. It's not just drag, but a self-righting force that applies to any rotary wing aircraft. It can be called "retreating blade stall" but it doesn't need to stall, just change the lift of the blades. Basically, when there's wind over the blades, the advancing blades get extra lift and the retreating blades lose lift. Due to gyroscopic precession, this translates into a torque that tilts the drone and makes it accelerate to catch up with the wind. You see in the video that the drone tilts in the direction the truck is moving, then as it catches up it rights itself. This is also due to how the algorithms are guessing at where up & down actually are, but that's dictated by this effect of the wind over the blades.

[@technicalfool]

You're not wrong. Anybody trying to fly a cheapo toy at any speed quickly discovers that the rotors start to act like big circular wings as far as flight characteristics go. This might be a good experiment to revisit with a racequad capable of operating in HORIZON or ANGLE mode. A small 3 inch Tinyhawk, Whoop or something similar would probably be a good one that wouldn't break the bank. They generally have pretty powerful brushless motors and a flight controller that can overcome that effect, even when you're bombing along outside at stupid speeds.

[@TheLukaszpg]

What an essay. And wrong!!

[@excrubulent]

@@TheLukaszpg I do apologise for putting effort into explaining the concept thoroughly. I'd ask you to explain your disagreement, but that might stray into essay territory, and you wouldn't want to be hypocritical about that complaint.

[@redtoxic8701]

​@@excrubulentlol

[@TheReaverOfDarkness]

Also it depends how the drone reads out its own buoyancy. If it uses an internal weight, it will try to resist the motion of the air pressing it to accelerate with the truck. If it uses laser motion detection, then it will try to accelerate with the truck and resist its own inertia. If it uses both, then what happens depends on its programming. The user input in the controller can also bias the outcome.

[@willo7734]

Really awesome demo! One of the best science channels on YT

[@qwertiee]

I was literally wondering this a couple weeks back. Love the video!!

[@davidanderson5310]

5:00 The balloon doesn't change position, but it does change orientation. When the truck accelerates forward, the helium-filled part moves forwards and the the duct tape moves backward. Because they're connected, this puts an angle on the balloon.

[@davidanderson5310]

5:45 I should really stop commenting mid-video.

[@bestboisoupsoup]

​@@davidanderson5310you mean 7:45 ?

[@billrobert3226]

85 people liked your comment mid video 😂

[@creativecarveciteclimb5684]

7:05 Correction here: There is actually a small pressure difference from the front and back of the truck, as the air has mass, therefore it has inertia and wants so stay. But when the truck accelerates, the air is compressed slightly at the back.

[@WhatTheHex]

Yep, just like why helium balloon floats, there is pressure difference between top and bottom due gravity acceleration.. and car acceleration creates also pressure difference to whole area.

[@jackreno12]

Exactly what I was thinking, thanks for saying it. If the balloon were free-floating right towards the back of the van, you might actually see it move forward a bit as high pressure air momentarily accumulates at the back of the van. Or it might spring backward and forward slightly with the air around it.

[@shouryatripathi7405]

Correct 💯

[@Sniperboof-of1yj]

I'm having trouble understanding why the balloon isn't moving forward but if u put it in a car it will do exactly that, Does space and acceleration matter also? Like it makes sense that it would move forward in a smaller container because it doesn't need that much acceleration as the truck?

[@9e9bab]

@@Sniperboof-of1yj As Action Lab explains, the balloon proper wants to move to the front of the truck, but the ballast wants to move to the back. Since the ballast was chosen to match the lift of the balloon, its rearward inertial force is equal to the forwards "lift" vector from the balloon. This only works because inertial mass and gravitational mass are equal. (Which apparently is not well (or just widely?) understood.)

[@azup8235]

2:02 for people who just wanna watch their video in chrome and be happy about it

[@abhilashravichandran]

❤

[@altjx]

lmao.

[@immac314omnia]

LOL

[@culhacol]

0:20 did you actually buy a fish just for that?

[@TheChrisLeone]

I'm assuming he gave it back or actually wanted a fish. Hopefully man didn't just flush it

[@MelissaAtwell]

Excellent work! Thanks for creating this video

[@Bodyknock]

Another way to think about this is, from the frame of reference of inside the truck, it’s the same as if the gravitational force vector shifted by having the extra horizontal acceleration vector of the truck added to it. So gravity no longer points straight down for things inside the truck, it points diagonally down with a slightly greater magnitude. The top of the balloon moves opposite that vector’s direction, since it’s lighter than the surrounding air, and the bottom moves toward that diagonal direction, since it’s heavier, which twists the balloon in that diagonal direction. Theoretically if you kept accelerating at the same rate in a straight line long enough the balloon would settle into floating along that diagonal line.

[@blahbaconblah]

I agree. If this was recreated in a vehicle with more acceleration capabilities, we would see the balloon "twist" forward more and it could even begin to float "upward" (upward in this case would include moving forward as the pressure gradient in this vehicle is now pointing down and back towards the rear of the vehicle.) along the vertical axis of the pressure gradient as that pressure gradient is maintained. Unfortunately, this vehicle accelerates very slowly, and its acceleration slows very rapidly. A higher performing vehicle would be superior to more accurately illustrated these effects.

[@unknownhours]

So I was curious, and it turns out someone measured the density of all the parts of the human body. The density of most organs and tissue is between 1.03 and 1.06 g/cm³. Bone can vary between 1.92 and 0.98 g/cm³ depending on the bone and the part being measured. Teeth are 2.75 g/cm³. For reference, water is about 1 g/cm³.

[@denizalicesme9797]

So what is the average density of a human?

[@unknownhours]

@@denizalicesme9797 A bit below 1 with lungs inflated, a bit above 1 with lungs deflated.

[@julianbrelsford]

Unknownhours with access to a swimming pool, the last bit is fairly easy to check for one's own body. Fill your lungs up and try to float. Empty your lungs and try to float. Either way, you'll probably have to hold your breath because humans aren't buoyant enough to keep the mouth or nose to float above the water without actively swimming in some fashion

[@DANGJOS]

​@@unknownhours Which is why I sank to the bottom of the pool when I blew the air out of my lungs when I was younger. *Please never try this!*

[@BillyViBritannia]

​@@DANGJOSlying down on the pool floor is pretty fun if you can hold your breath with no air tho ...

[@snorman1911]

Wait, didnt you test this in an elevator and the drone had to be flown up or down to keep up with the elevator?

[@candyman9635]

A change in height means a change in potential energy. That energy has to come from somewhere so you would have to increase the thrust to keep up with the elevator. If the truck were going up a hill you'd see the drone eventually crash into the floor of the

[@newera478]

Working against gravity (y-axis) is different compared to moving with the gravity (x-axis).

[@seanzoan]

Would be interesting to see though too

[@technicalfool]

The barometric sensor in that particular quad would quickly have it smacking into the floor or ceiling as air pressure increases or decreases with altitude. With no barometric sensor, it'll probably do more or less the same thing but would stop moving once the elevator was moving at a constant speed and no longer accelerating. It would also resist hitting the floor due to ground effect, or stick to the ceiling due to being sucked up against it by the props.

[@ttk.videos]

Thanks for the clip. I was wondering about this question since i was a kid, and you have answered it thoroughly.

[@WeatherMan2005]

I've needed this information my whole life! Thanks

[@XavierAway]

5:00 it did move, there’s an ultra low frequency compression wave moving from front to back a few times as all the air particles in the space attain the change in velocity. Hence why you see it wobble very slowly in place with that wave. Edit, you did mention this later to be fair.

[@MrZcar350]

You can also see the balloon tilt slightly forward as the weight to offset its buoyancy has higher cross-sectional density compared to the balloon itself to its inertia is hard to offset.

[@takanara7]

It also depends on how the drone is programmed. If it's just at a constant setting, or if it's using vision it'll move with the air. If it's station keeping using GPS or an accelerometer it will stay still relative to the earth, and move inside the truck. It's not a one thing or the other thing, it depends on the settings.

[@darrennew8211]

@@MrZcar350 That also happens because the floating point wants to go forward and the heavy wants to go backwards. If you tied the balloon to a string and accelerated, the balloon would move forward. (Ah, he says that later.)

[@DevDreCW]

we got gaslit for a good few seconds there lol

[@DANGJOS]

@XavierAway What you say is true, except the wobble part. The wobble comes from the torque caused by the difference in buoyant force between the top and bottom of the balloon. This is because the top balloon part has a large surface area and a low mass. The pressure wave, on the other hand, means that the balloon will not 'feel' this buoyant force until a few milliseconds later after the wave hits it. This timeframe is far too short to actually see any movement, so it's not responsible for the wobble. The torque from the buoyant force is the reason.

[@al-ameenademola3156]

That balloon was crazy steady

[@FatherGapon-gw6yo]

No mass

[@beanapprentice1687]

@@FatherGapon-gw6yo yes mass

[@SasamuelTheCool]

@@FatherGapon-gw6yo yes mass

[@Leonvolt28]

Do You Want a Balloon???

[@Crafter_H]

So im confused with the helium ballon. I remember your video with it before and it gets moved towards the front of the van. Why did it not do it this time and did it the last time

[@BenAlternate-zf9nr]

The inertia of the extra weight added to make it neutrally buoyant holds it back, exactly balancing the forward pressure force.

[@Qwarzz]

@@BenAlternate-zf9nr Yes, this was explained in the video. The top of the balloon moved forward as you'd expect from lighter than air balloon but the weight at the bottom did the same move backwards. Balloon tilted at the center of mass.

[@paddor]

The helium balloon in the old video was lighter than air.

[@Brainyplanet]

It is because it's patched in the Earth 2024.8 update

[@heelercs]

Did you watch the whole video?

[@Brocambro1]

Asked my physic teacher this question when I was in 7th grade. I was a very inquisitive kid, the rest of the class not only made fun of me, the idiotic teacher apparently not able answer my question just ignored me, I remember how angry that made me feel, for years this phenomena always puzzle my mind and finally someone is able to scientifically explain to me in this video why birds or flies who enter a bus in motion by a windows don't get crashed at the back window my props to u man!

[@Laptopsigmagamer]

I have been asking myself this for the past 7 years, finally someone who explains it

[@TheTyisawesome]

Damn she really gunning it out those "GO!” 'S ahahaha😂

[@igxniisan6996]

Literally every company he sponsors somehow becomes his most-used/ new-favourite! 😂

[@Sashazur]

Sponsors are needed to make a living with KZbin. I don’t really care what is his favorite this week!

[@angels5552]

But like yes, Opera is VERY useful

[@Eriksen-wp3tv]

​@@angels5552 So useful it sells all your info

[@wilko2]

@@angels5552 Opera is just as useful as any other web browser, there's nothing special about it. It is Chinese spyware btw (as opposed to American spyware like Chrome, Edge etc)

[@ArthurKhazbs]

@@angels5552 Not as useful as your personal data is to them.

[@solepsis]

You can see the weighted portion of the balloon move forward as expected on acceleration (due to all the air moving backward and displacing the balloon mass forward), but I think the acceleration just wasn’t fast enough to get the full effect vs. the car example. A neutrally buoyant free floating ballon on the car would go all the way up to the windshield if it weren’t tied down like the one in the car clip.

[@dahahaka]

The balloon is moving forwards, the weight backwards (due to inertia). Since it is neutrally buoyant it stays in the same place, but if you look carefully you can see a torque being applied, due to the weight and the balloon trying to move in opposite directions, the effect is very small tho.

[@ninjacuttingonions5861]

​@@dahahaka Bro you need to learn how to use periods. Your comment is almost unreadable.

[@dahahaka]

@@ninjacuttingonions5861 My punctuation seems to be fine I just tend to write very complicated, albeit grammatically correct, sentences. There were some mistakes tho and I fixed them :) sorry about that

[@ame7165]

it doesn't BECAUSE it's neutrality buoyant. this is assuming it's perfectly centered in all the axis. neutrally buoyant just means it has the same buoyancy as the fluid it's suspended in. just replace the air with water, and replace the balloon with a colored drop of water, and i think you can visualize the colored water drop not moving at all because it's all the same buoyancy. the non-neutrally buoyant one moves forward because it's less buoyant than the fluid that it's suspended or floating in. to imagine how that one works, imagine the truck being filled about 80% with water, and then imagine the balloon filled with normal air just floating in the middle near the ceiling. then imagine the water all sloshing towards the back when the truck accelerates. the pocket of air will move forward, so the less buoyant balloon will as well. it's just harder to picture when it's air, since we can't see it

[@frijoli9579]

@@dahahaka , well grammatically, the last comma should be a semicolon. lol

[@OneAndOnlyEfie]

FINALLY! MY LONG-LIFE QUESTION HAS BEEN ANSWERED! I kept on figuring out how does an insect flies inside a moving car. Thank you!

[@pixelbee42314]

I've often wondered about this very question, so thanks for making this video so I can finally know the answer!

[@hereforthefreewater]

That nuetral buoyancy trick is frickin awesome. Cheers.

[@abramisme]

You guys make a great team!

[@solandri69]

The cool thing about the balloon is that it's basically the truck in miniature. If you imagine a fly inside the balloon, it will experience the same thing as the drone in the truck. (It's hard to make comments on these videos because James already covers all the little caveats and side notes I'd normally bring up.)

[@User-jr7vf]

hmm... not sure about that. There are crucial differences. The balloon is filled with helium, the truck is filled with air.

[@theconservativeknight1883]

Short answer: The momentum or kinetic energy of the truck is transferred to everything within it as it accelerates, even the air. Therefore objects within the truck despite not making physical contact with the truck itself will accelerate with the truck due to the air serving as a medium for the kinetic energy or momentum to transfer to the objects.

[@sajid279]

No the container was closed

[@Connorses]

I love this one!!! The helium balloon moving forward when the car moving forward is actually the craziest part of this video. Bouyancy is weird.

[@karangupta4615]

4:36 important to note that the mass is 17 grams, the weight is quite literally nothing.

[@UnderTheSkin13]

It's good to see a scientist have the same verbatum reaction to things as Beavis and Butthead.

[@RodCornholio]

Cool

[@gabor6259]

Technically he's an engineer.

[@RodCornholio]

@@gabor6259 Technically, anyone using the scientific method is a scientist. (Whether his methodology is very good, scientifically, is debatable).

[@drunkenhobo8020]

Heh heh heh heh. You said "bate him".

[@viniviper2973]

Are you telling me, no one has ever dealt with a fly in a moving train?

[@chrisolson4405]

Trains aren't as common as they used to be in the US.

[@Micke12312]

Well it was about acceleration

[@varunv.p.7180]

Would never expect air to exert enough force to keep the drone (roughly) in place! Cool demo! Used to think about this mentally for many years, thanks for making it real!

[@cloudoftime]

But there is not opposing force, right? It doesn't really need to exert any force, just stay mostly where it is, which it is doing.

[@ervin6270]

Why are people somehow turning dumb, why can't u just realize it's the same concept as if you threw ur lighter in the air while driving, it won't just fling back at the same speed car is driving, and when the car accelerates it's the same as you or anything in the car gets pushed back... Why was this video necessary at all???? How low is the general iq jesus

[@K3nn4rD-S]

Dude i am so excited to see this. I was wondering about this question since i was a kid and asking myself how flies behave in a moving car. But in the past years i had the same thoughts about drones :D

[@bcreason]

I used to drive a van in the winter. When you hit the brakes cold dense air from the back rushes forward and replaces the less dense warm air in the front.

[@hrmzk]

Fr? That’s quite interesting!

[@DudeUnperfect21]

This guy answers every question I've had about things nobody else pays attention to

[@davidyoder562]

Ooh, someone violated the terms of his truck rental agreement! Uhaul has a clause saying you're not allowed to show their branding in any type of production. (I recently rented one and noticed this provision.) I hope no one gets in trouble!

[@david-cn1xv]

I had this exact question since I was a kid when i got a small rc helicopter, no one ever knew how to answer it to me. this video is perfect!!

[@Miraj7-q]

Finally my curiosity is breaked just because you after 7 years Thank you ❤🎉

[@SigmaJAD]

Was the truck lighter when the drone took off?

[@Dipole__]

Wait, now i'd love to know this lol🤔🤨 My guess is, it remained the same weight

[@SigmaJAD]

​@@Dipole__ so do I but.......

[@MuSlaaf]

vsauce2 made a vid around this exact thing (except with birds)

[@SigmaJAD]

​@@MuSlaafthx - will look out. Curious

[@kamnafar]

No it was a perfect match.

[@rickie_]

Now do it with a vacuum chamber...

[@Rafael-vm7kj]

Yeah! Put wheels, engine and drive that vacuum chamber at 70mph so we have more data to do some scientific conclusions.

[@solandri69]

That's essentially astronaut Dave Scott dropping a feather and hammer on the moon. Just rotate it 90 degrees, and understand that gravity and acceleration are indistinguishable. So the moon's surface is like the truck's rear "accelerating" towards the feather and hammer.

[@Qwarzz]

Neither balloon nor the drone would fly in vacuum tho :)

[@alexuk1919]

1:39 Even big KZbinrs use sci-hub 😂

[@MoonGlow22]

Its a great tool

[@paaabl0.]

Science must be free!

[@reyals66]

I had asked a similar question to my Mathematics professor in school about twenty odd years ago and never got a clear answer. Thanks for posting this!

[@neomproductions]

I love @TheActionLab but during the balloon experiment I was reminded of the famous saying "the definition of insanity is doing the same thing over and over and expecting different results" lol. great video!

[@cuculuc]

Opera ❌ Firefox ✅

[@Antrunswag]

Chrome ✅

[@tommysk8r94]

Brave✅

[@EpicMinecraft7978]

Librewolf ✅️

[@LarryTheTugaGamer1511]

FIREFOX FOREVER!

[@tjthr]

Duckduckgo

[@noahtemple8312]

8:54 instantly gets flashbacks of Barbara from Finding Nemo 😂

[@jamesphillips2285]

0:40 Answers my question about GPS possibly messing up the experiment.

[@stewartmoir9464]

That along with the slight change of the angle of the floor as the center of mass moves on the suspension

[@hariszark7396]

I had this question since I was a kid in the '80s. Thanks for answering. 😁👍

[@NoTime4BS7]

Making this comment while the video is paused. The more mass the object "floating" in the truck has, the more it will move to the back of the truck during acceleration, if the rate of acceleration remains constant. As the acceleration tapers off to a cruising speed the objects will eventually keep up with the truck. Now do this test with the back of the truck open to see how the vacuum created at the rear of the truck makes a difference. Edit: LOL You did open the back! Good man!

[@PaHDoMNblu_4ell]

Thanks for reporting bug with a balloon! We will fix it in the next update of the simulation engine

[@ProgressiveEconomicsSupporter]

Ok, the free floating balloon is a little surprising, since I seem to remember you and Derek from Veritasium had a different result with an attached helium balloon (in a regular car)

[@candyman9635]

As in the balloon was tied to the car which was moving? Makes sense to me. I'd expect the balloon to move.

[@mstreich]

So the age old question: If the truck is moving at the speed of light, can you fly the drone forward and thus faster than the speed of light? 2:44

[@BenAlternate-zf9nr]

If the truck is moving at the speed of light, length contraction means there's no room to fly the drone, and time dilation means it wouldn't have any time to fly anyway.

[@xhaidendsouza7380]

@@BenAlternate-zf9nrwell that’s not the entire story of how it works because it would be contracted and dilated for an outside observer but for the drone itself these effects would not be present

[@snorman1911]

You get diminishing returns. You will be 0.9999 and the drone will be 0.999900000000000000001 light speed.

[@iLLadelph267]

let's all not forget, anything with mass cannot move through space at the speed of light

[@DUEL.FATALIS]

The answer is yes

[@sharpshooter2398]

THANK YOY!!!!! I’ve been wanting to know the answer to this for literally ages!!

[@sumedhpradhan]

This question was in my mind for years... Finally someone talked about it

[@Zomerlad]

Cool experiment

[@depressedeboy]

I ACTUALLY KNEW THIS ONE

[@michaelripley4528]

I once jumped inside a Boeing 737 🤷🏼‍♂️ We all died😞 0:01

[@ancientone1]

This question has been keeping me awake at night for years. Thank you.

[@JMazzaTaz]

This is similar to the “birds in a truck” paradox. If a truck overloaded with birds in flight crosses a bridge with a specific weight limit, would the truck in question be too heavy? Or since the birds are in flight (inside the trailer), would the truck NOT be too heavy? I know the answer, but this video reminds me of that. Thanks for the upload, bro! Keep on keeping on 👊🏼

[@JohnNecirRebellion]

Next up, hopping in an falling elavator before it hits the ground.

[@pedroakjr2371]

2:06 For a fragment of a second I though it was Dillion Harper.

[@leonardo9259]

Coomer

[@KevinTyler123]

TIMESTAMP: 2:45 The experiment

[@viceroybolt3518]

Prediction going in, an object in motion stays in motion unless acted upon an outside force, and the contained volume of gas is not in motion. Honestly you got me bamboozled on that one! Flight physics knowledge improved thank you!

[@SubstreamNewsNetwork]

Epic experiment! Thank you for sharing!

[@phizicks]

This destroys flat earthers and their "spinning" ball issues.

[@omnipresentvideo7686]

Oh cone on, they're way too dumb to be discouraged by a little proof and science!

[@ArthurKhazbs]

"But what if…" What if flat earthers are higher dimensional beings, to whom the three spatial dimensions of Earth seem flat?

[@revolutionnow5227]

Actual it proves earth is flat

[@VioledyFN]

​@@revolutionnow5227 actually it doesn't. Since we aren't floating in mid air at all and are touching the ground of earth itself. It means we have weight. The Ballon is boyant which means it weighs the same as the air around it. That's why the weight was needed to bring down the helium which is lighter than air. So back to what I was saying. We are not in mid air which means we're not boyant which means there's a gravitational pull on us. Which means we'd be thrown off the planet. But we're not because of our friend gravity. And gravity works more than just on a 2 dimensional surface. It's 3 dimensional. That's why we don't go flying off at all.

[@h.n.t.d7963]

owh please god, dont spawn them here

[@solreaver83]

Take that flat earthers

[@matthewb840]

I’m not a flat earth but this has nothing to do with the globe being round.

[@solreaver83]

@matthewb840 it was a humours jest. Flat earthers arbue if the world is a spinning globe a plane would just have to stand still and the earth would rotate beneath them. This proves why that is t true.

[@Amankumar0503]

8:42 I feel the same even without moving 😭

[@krissynull]

that was crazy I opened the comments and accidentally clicked this timestamp at the second before so like I didn't even lose my place in the vid

[@xdsam24]

​@@krissynull same

[@krist6074]

I think it's really cool how the balloon is somewhat bouncing around it's center of gravity. I believe this indicates that the air inside the truck is somewhat slushing around too, like water would? Very fascinating!!! Thanks for sharing!!

[@dangill1227]

You could have replaced the tape with an air filled balloon (or several with the equivalent weight) to avoid the rotation of the balloon with the tape. Great video. Well done 👍

[@gossamera4665]

I'm gonna guess no because there's an air bubble formed around the moving truck, if anything the drone would get pushed down from the air flowing into the open compartment. Edit: Oh you didn't leave the back open, well that's misleading.

[@marekwiater2454]

Man those are the questions we should be asking. If they learned us that way in shool i would have been a second Einstein

[@kaleoscreations]

Maybe the real Einstein was the friends we made along the way

[@bulletgamesnl9468]

1:23 it protects you from cryptomining?!?! Wtf is that supposed to mean😂😂

[@TEAM__POSEID0N]

They probably meant to say "cryptomiming". That's when a strange guy from Paris shows up at your house (usually wearing a striped shirt, a beret and very thick make-up), refuses to speak and starts making a variety of gestures and body movements that you can't understand. Obviously, we all need to be protected from cryptomiming.

[@dxpamane7618]

There are ways of getting crypto mining code inside of others devices to hijack their computing power and mine crypto remotely

[@travistucker7317]

​@@d83f90The one that went up the hill for the water?

[@JustinLe]

some websites will use your computer to mine crypto currency even you are on them

[@Bosnian.Spartan]

​@@dxpamane7618 how can you stop/prevent it?

[@kk-cy3sz]

Great video! I was always worried if someone at my front coughs my face would run into someone’s cough

[@milli_on4451]

This is very interesting! Thank you for sharing with us!

[@LucyWoIf]

2:47 (save your time)

[@andreiconstantin1227]

thx

[@ECL2VR]

i love action labs

[@hughhemmerich8854]

Myth busters already busted it

[@Notmeggii]

Many people nowadays have no idea who the Mythbusters are

[@Yuhuhnuhuh]

Dont spread hate dawg

[@brosephbroman7564]

Some of us don't watch TV.

[@fuzznut25]

Your experiments are awesome thank you

[@seanzoan]

I really asked myself this since some time. This was so interesting on so many layers. I have to watch this again, when I'm more receptive again 😅.

[@SepticEmpire]

Same reason we don’t go flying Mach 10 out the window whenever we drive a car

[@reid3031]

...because we sit in a seat? Doesn't seem comparable.

[@4lmighty_L0af]

​@@reid3031yeah LMFAO

[@SepticEmpire]

@@reid3031 technically we’re not because nothing on an atomic level actually touches anything But it’s the same principle tho maybe a better example is being on a bus or subway and jumping in the air. But the principle is that despite being in motion you still aren’t moving. Only time that really happens is when the vehicle is stopping or going. Regardless if you’re in a seat or standing or jumping or floating.

[@reid3031]

@@SepticEmpire "technically we're not because nothing on an atomic level actually touches anything" My brother in Christ- Also, it's still not comparable with the video because if you actually watched it, you'll see that something drastically different happened with the balloon versus when I'm pressed into my seat during acceleration

[@SepticEmpire]

@@reid3031 didn’t say it wasn’t different I said it’s the same principle And it’s true atoms don’t touch it’s actually pretty interesting Also if it’s not comparable why did the video literally compare them to show the difference it’s literally why I made the comment saying it’s similar

[@DACoutBack]

Guess @ 2:46 = Move along with the truck.

[@digs-]

My guess is stay in place relative to the ground. I’m about to find out

[@shade5554]

Drone will move forward in truck because of air gathering around at the back of truck while accelerating

[@Eightbollz]

I think that only works for a balloon :)

[@shade5554]

@@Eightbollz I was wrong about the drone, haha.

[@abdumka]

I can't see any benefit from this video in my daily life, but thank you so much! This is one of the questions that were in my mind since I was a kid. Now, try doing it in vacuum

[@cometeng44]

In 1967 I was in the Army and we were going about 35 miles an hour in a truck. The truck was covered on three sides. Only the back was open. There was a fly, flying inside of the truck as we were going. I thought that fly must be flying at 35 miles per hour. Your video reminded me of that time.