What is Balloon: Definition and 482 Discussions

A balloon is a flexible bag that can be inflated with a gas, such as helium, hydrogen, nitrous oxide, oxygen, and air. For special tasks, balloons can be filled with smoke, liquid water, granular media (e.g. sand, flour or rice), or light sources. Modern day balloons are made from materials such as rubber, latex, polychloroprene, or a nylon fabric, and can come in many different colors. Some early balloons were made of dried animal bladders, such as the pig bladder. Some balloons are used for decorative purposes or entertaining purposes, while others are used for practical purposes such as meteorology, medical treatment, military defense, or transportation. A balloon's properties, including its low density and low cost, have led to a wide range of applications.
The rubber balloon was invented by Michael Faraday in 1824, during experiments with various gases. He invented them for use in the lab.

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  1. M

    Will my weather balloon work in the Stratosphere?

  2. T

    Engineering Stone dropped from an ascending balloon takes 10s to hit the ground -- Find the height of the balloon

    ay = -9.8. Vy = -9.8 + v0*Sin0. y = -4.9*t^2 + v0*t*Sin0. By using formula of y, my solution was -4.9(10s)^2 + (10m/s)(10s)Sin0. I assumed that y was equal to 0. Since -4.9 is m/s^2 the answer would be -490m + 100m*Sin0. Therefore I assumeed Sin0 = 490/100.
  3. H

    B Where the extra energy comes from?

    Let's say you've created a very large balloon that doesn't explode in a vacuum and filled it with a gas lighter than air. Next, attach the balloon to a basic electric generator with a very light rope and place the balloon in a vacuum tube. Due to the balloon's weight, it will descend in the...
  4. Lotto

    What helium mass in a balloon to make it bouyant in air?

    I suppose that the temperature is the same for the helium as well as for the air. So ##\frac 43 \pi r^3 \rho g >m_{He}g+4\pi r^2 \sigma g##. I would determine the density of air from ##p_0 \mathrm d V=\frac{\rho \mathrm d V}{M_a}RT##. So ##m_{He}<4\pi r^2\left(\frac{p_0M_a r}{3RT}-\sigma...
  5. Entropix

    I Hydrogen balloon experiment -- How high can it rise?

    If we launch a hydrogen balloon from the Earth surface (let's say it has a 2 meter radius) and assuming it's strong enough so it doesn't pop/disintegrate (it's made out of carbon nano-tubes). Where this balloon will stop? I'm more interested in the exact altitude it reaches or if it will keep...
  6. C

    Helium balloon energy conservation

    For this problem, How can energy be conserved if the bit highlighted in orange is true?Many thanks!
  7. Ivan Seeking

    News Chinese "weather" balloon shoot-down over US

    Balloon shot down. It sounds like we do plan to retrieve it. They shot it down before it was over international waters. [Thread split off from the Weird News thread]
  8. Lotto

    B Can we say that a charged balloon has a center of charge?

    Doing so, we can consider the balloon to be a point charge (approximately). Can we do it in this case, when there are only electrons on its surface? Or is it stupid and we can't do it under any circumstances?
  9. KingoftheChaosEmpire

    My balloon technology (the LDH honeycomb)

    Ok so I don't know how to post a new thread so I'll post my question here: So I have been developing this balloon technology (the LDH honeycomb) and I've since made changes to it: First, instead of making compressive structures out of rigid LDH honeycomb, I've decided to use tensegrity...
  10. P

    B Confusion when considering pV=nRT in Two Balloon experiment

    This is the Two-Balloon Experiment: https://en.wikipedia.org/wiki/Two-balloon_experiment#cite_note-MW78-1 The claim on Wikipedia which I am a little confused over is that when 2 balloons (at the 2 red points) are connected via a tube, the smaller balloon at a higher pressure would push air...
  11. smiddleton26

    Misc. Expand balloon with static electricity

    The idea is to wrap a balloon in several layers of material, similar to that used in electrostatic adhesion wall climbing robots, and run power through the layers. The electrostatic charge on the layers outside the balloon will build up and the air inside the balloon will begin to become...
  12. L

    Building a small hot air balloon

    Hypothetically how can someone build a small hot air balloon? I want to navigate a 360 camera to the air without needing a drone. Just a balloon, camera, and string to keep it from getting away. Maybe a remote fan to pull it down if string gets loose.
  13. L

    Calculating the Radius of a Hot Air Balloon to Withstand a Load of 300 kg

    The result is supposed to be 12,2 m but every time I get 8,016 m... I used for example this formula >r=m/[(density of air-density of hot air)*(4/3)*pi] For density I used > rho=(p*M)/(R*T) Am I forgetting something? Thanks in advance.
  14. F

    Hot air balloon mass including increase in mass with balloon volume

    Hi guys, M can then be split up into 2 components: the mass of the payload which is known, and the mass of the wing. The wing material has a known thickness and density meaning its mass is given by: surface area of wing* mass per m^2 (mass m^2 is used as density and thickness are known so an...
  15. L

    A reflective spherical balloon

    From ray tracing I would say that the image is upright. Using the equation ##\frac{1}{p}+\frac{1}{q}=\frac{1}{f}## with ##f=-\frac{R}{2}=-2## and ##M=-\frac{q}{p}=\frac{3}{4}## I get ##p=\frac{2}{3}cm\simeq 0.67 cm##. Is this correct? Thanks
  16. DaveC426913

    B Can you fall below the horizon on an expanding balloon?

    This scenario came up (as a dream) in a sci-fi novel (Robert J. Sawyer's The Terminal Man). Two people of height h, initially within sight of each other, at d distance apart , on a huge balloon of radius r. As the balloon expands, they might or might not lose sight of each other over the...
  17. Guidog77

    B Balloon rocket- What happens inside and why the reaction?

    The law of action and reaction is the explanation that I see everywhere. But I can't find anywhere what exactly pushes the balloon in the opposite direction as the air coming out. Air molecules come out to where pressure is less. What exactly moves the rubber balloon in the opposite direction...
  18. Freaky Fred

    B Helium Balloon: Explaining Special Relativity Effects

    Hi, guys o/ Suppose a person sees a helium balloon moving horizontally at close to the speed of light. From this perspective, the observer will see the helium balloon contract in accordance with special relativity. If helium contracts to the point where it is denser than air, will it fall? how...
  19. D

    Calculating Hot Air Balloon Volume & Lift

    Volume of hot air ballon V=((4/3 pi R^3)/2) + (1/3 pi h (R^2 + r^2 + Rh) = 2956.24 m3 Balloon: R=9m h=15m r=1m m = 750 kg H = 5000m T = 373 K p1 = 101300 Pa p2 = 50650 Pa M(air) = 0.029 kg/mol F = mg - 7350 N
  20. S

    Balloon inflated by external vacuum: why won't it burst?

    Why doesn't the balloon burst in this video? To me it seems that the differential (guage) pressure between inside and outside the balloon is what matters, and I would think it would be the same as a balloon inflated in the usual way. https://youtube.com/shorts/3HZ0JkgtpDU?feature=share
  21. emzy168

    Calculating the speed of an airstream leaving a balloon

    I'm really not sure how to start this one!
  22. F

    Flow of air through an open tube with a balloon

    I hope you guys don't mind a bizarre question from a novice. I've learned just enough about fluid dynamics to be dangerous. Assume that we have a straight, rigid tube with a constant inner diameter. It's not long, let's say it's around a foot (in case that matters). We cut a chunk out of the...
  23. N

    Stratospheric Balloon question

    I have gathered the formula: F(Bouyant force) - (Mballoon + Mpayload)g - (Mhelium)g = (Mballoon + Mhelium + Mpayload)a But i can't seem to figure out what is the buoyant force to find a. Or am i mistaking something?
  24. G

    Exploring Balloon Volume in Ocean Descents

    Hey fellow physics enthusiasts, how might the volume of a balloon change as you bring it down deep into the ocean (consider both adiabatic (quick) and equilibrium (slow) descend). Looking for insights what most likely will happen, for simplicity we can start with a thin (##t << R##) elastic...
  25. T

    Understanding Balloon Charges and Interactions

    Balloon A is + as negatively charged rod attracts it Balloon B is - as Balloon A attracts it. Since Balloon A (+) repels balloon C so it means Balloon C is +. Balloon D attracts Balloon Balloon B (-) so it means Balloon D is +. Balloon E is neutral as negatively charged objects and neutral...
  26. H

    What is the Differential Equation for Airflow in a Balloon?

    I have a problem. The task is to develop an differential equation of the airflow of a balloon. I know that it is dependent on the volume and pressure. But I can't get a good differential equasion. Can someone help me? [Thread moved from the technical forums, so no Homework Help Template is shown]
  27. Baluncore

    Project Loon, Stratospheric balloon

    Project Loon is a network of stratospheric balloons designed to bring Internet connectivity to rural and remote communities worldwide. https://loon.com/ There is one being tracked, between Reunion and Mauritius in the Indian Ocean. https://flightaware.com/live/flight/HBAL125 Another one over...
  28. T

    What force causes a balloon to float?

    When I blow a balloon with CO2, it falls as it is heavier than air. Then it is gravity that causes the balloon to fall. When I buy a balloon filled with helium gas from a store, it floats as it is lighter than air. But what force is causing the balloon to float?
  29. L

    Creating a Long Life Helium balloon

    Why do metalised film helium balloons only last about a week? Could I improve this result and make a balloon float for a year? (and don't cheat and say just make it bigger) how do I stop it leaking? Are there any better materials to make it from? (unlimited budget) As I understand aluminium...
  30. rofldude188

    Faraday's Law - Balloon Problem

    a) Calculate the proposed induced emf along the equator of the balloon. (horizontal equator), at the moment indicated above. $$V(t) = V + Ft \implies \frac{4 \pi r^3(t)}{3} = V + Ft \implies r(t) = \sqrt[3]{\frac{3V+3Ft}{4 \pi}}$$ $$\phi = B \pi r^2(t) = B\pi (\frac{3V+3Ft}{4 \pi})^{2/3}$$...
  31. S

    Stone released from a rising balloon

    I solved it in ground frame like this: -30=5t-5t2, and then solving for t which comes out to be 3 sec.(displacement is 30 m downwards) Now, I am not getting the same answer when i am trying to solve it in the frame of the balloon. W.r.t. balloon, the initial velocity is zero, displacement is...
  32. J

    How to calculate the time required to open a valve to inflate a balloon?

    Problem Statement: I have a canister (0.15L Volume). This will be filled with compressed air. A solenoid valve attached has a diameter of 2mm, and the air will flow through this into a pipe which leads to a balloon. The pipe diameter is 3mm, with a length of 300mm. The pressure required to...
  33. J

    Hot air balloon buoyancy problem

    Initially the hot air balloon is stationary so... FB=Fg ρgV=mg m=1319.2...kg FB=Fg=12941N In the air... a=2d/t^2=0.933...m/s^2 Fnet=FB-Fg (1319-x)(0.93...)=12941-(1319-x)g x=114.6 kg but apparently this is wrong?...
  34. T

    Bouyancy force -- What mass can the balloon carry?

    In a I used FBouyancy - FBalloon -F mass = 0 rewrote mass as a product of density and volume to obtain; m= v(densityair - densityHe) m= 1031.5kg.I am stuck in part b. I have this formula called Barometric formula which ı should use; P = P0 * e((-P0*g*h)/ P0 So what I understood is that...
  35. Z

    What does a helium balloon do on the ISS vs in open space?

    What does a helium balloon do on the ISS . most say, its a 0 g environment, but is it really the same as intercosmos travel "0g"? I saw a video of helium ballons on the vomit comet, where during the "0 g phase" the helium balloons went to the floor, while all other things floated. I would...
  36. Quentin_Phys

    Relationship between the Volume of a balloon and the time it takes to deflate

    I would like to ask a question on whether there is a proportionality between volume of a balloon, and the time it takes to deflate. I have conducted several balloon hovercraft experiments. I need to find the relationship between the amount of air pumped into the balloon and how long the...
  37. K

    Pressure Difference Between the Inside and Outside of a Balloon

    Hello all. I have a question about gasses and pressure: Is there a way to calculate how strong a material making up a balloon has to be to withstand a given pressure difference between the inside and outside? In other words, if I have a balloon I need to fill to a pressure of 10atm inside vs...
  38. T

    Exploring the Ideal Gas Law: A Balloon Problem

    Homework Statement Homework Equations Ideal gas law The Attempt at a Solution The solution to this problem assumes the pressure inside the balloon is the same as the outside pressure, i.e. atmospheric pressure. Is this a valid assumption? I would guess otherwise.
  39. S

    Why is the balloon sticking to the wall?

    When you negatively charge a balloon, by rubbing it on clothes, and then placing it against the wall, why doesn't the electrons move to the wall, causing the balloon to drop? I would have thought the electron transfers to the wall - therefore an example of conduction. Why is it induction and...
  40. Pat Trainor

    Keeping helium in an unsealed balloon?

    Along the same lines as an earlier post about helium and materials that wouldn't allow it to permeate it, I wondered if a helium balloon with a fill tube would actually need to be sealed. What I mean is, imagine a balloon that has been filled with a 20'-30' very thin tube that is still attached...
  41. Pat Trainor

    Need a material that can hold Helium....

    Experts, I'm in need of a balloon to hold an RF antenna aloft, and that can have a light (LED) in it. For cost & safety, it appears Helium is the choice. But everything I'm reading says that He atoms are so tiny they pass (eventually) through traditional balloon materials quickly. There is a...
  42. prashantakerkar

    Measuring the weight of gas in an inflated balloon

    What could be the method for measuring weight of gas in inflated balloon? Thanks & Regards, Prashant S Akerkar
  43. S

    How Is Work Calculated for a Gas and Balloon in Isothermal Expansion?

    Homework Statement The question is: One kilogram of a gas with a molecular weight of 35 is contained in a balloon. The initial conditions are 27 C and 0.025 m^3. The gas is slowly heated isothermally until the final volume is 0.05m^3. The atmospheric conditions are 100 kPa and 27 C. The p-v-T...
  44. V

    Designing Car Floatation Devices: What Alternatives to Sodium Azide?

    I need to make the design of car floatation devices. In my case, the airbag/raft is for floating the car in case of floods. I am considering to use Sodium Azide, just like in car airbags, but it inflates very fast and shrinks in a short time. Is there any other chemical reaction that can produce...
  45. T

    Air-powered water balloon launcher, Which weights to use?

    Hi all, first post. Bare with me. I've got a simple air compressor-powered water balloon launcher made using PVC. It works extremely well. But, I'm needing to make some "sighting charts" to predict where everything will land based on angle, loaded psi, size of balloon---and the wadding...
  46. G

    Movement of a balloon in dead air

    I had a helium balloon in my car tied so it hangs down by string toughing nothing. Windows are rolled up. Heat and AC are off. Air inside the car is not moving and car is parked with motor running. When I step on the gas pedal and car takes off forward balloon goes forward towards the...