sealed helium balloons
sealed helium balloons
I am doing a project on helium balloons and would like to know where and how far they travel once released. Why is it that I have never found a deflated one in my garden after a children's party? What is the effect of gravity, air pressure, buoyancy and velocity forces on these party balloons? I would really appreciate a prompt reply.
Hi Bolton,
Here I have some ideas. From the period table, why don't you look for where helium is and research on its property? And think about the gases in the air, what are the components in the air, and what are their percentage? If you want to know how far it travels once it is released, try to use the scientific method: make hypothesis first, and then plan experiments to prove your ideas. For example, buy some helium inflated balloons. Here I have a hint: to determine the balloon's volume first. However, I prefer you to do some research on the internet, or in your chemistry, physics textbooks first; they become helpful for making some hypothesis. I hope my comment helps you a little bit. Nice observation already, good work.
Here I have some ideas. From the period table, why don't you look for where helium is and research on its property? And think about the gases in the air, what are the components in the air, and what are their percentage? If you want to know how far it travels once it is released, try to use the scientific method: make hypothesis first, and then plan experiments to prove your ideas. For example, buy some helium inflated balloons. Here I have a hint: to determine the balloon's volume first. However, I prefer you to do some research on the internet, or in your chemistry, physics textbooks first; they become helpful for making some hypothesis. I hope my comment helps you a little bit. Nice observation already, good work.
James Chen
"A book holds a house of gold." Chinese proverb
"A stand can be made against invasion by an army; no stand can be made against invasion by an idea." --Victor Hugo
"A book holds a house of gold." Chinese proverb
"A stand can be made against invasion by an army; no stand can be made against invasion by an idea." --Victor Hugo
Can you tell us what you do understand? It will be much easier to start from what you already know and build on that than to start talking about all these terms from scratch.
That said, I study bird flight--so let me talk about the forces and how they work for a bird, and then you can think of how they might differ for a helium-filled balloon.
I apologize in advance if any of this is too simplistic for you; I'm not sure what your background is and what you will understand and what you won't.
Let's first consider a bird flying at some steady speed in zero wind.
Are you familiar with Newton's Laws? One of them states that force equals mass times acceleration. Acceleration is a change in speed through time--I'm sure you've experienced acceleration and deceleration (slowing down) in a car or on a bike. You can think of mass as weight; it's actually a little more complicated than that but I'm going to simplify as much as possible.
Now, you can apply multiple forces to an object; for example, you could push a trolley while someone else pulls on it. In that case, you add up all the forces and the result will equal mass times acceleration. If you are both pushing and pulling in the same direction, the trolley will accelerate in that direction. If you push one way and your friend pulls another, which way the trolley goes will depend on which force is greater and what direction the forces are applied in. If you are pushing/pulling in opposite directions with exactly the same force, it will go nowhere because the sum of the fores is zero. Make sense?
So let's go back to our bird, flying along. I said that it was flying at a steady speed, which means that it is /not/ accelerating (changing speed). This means that the sum of all the forces on it is zero.
The first obvious force that must be acting on it is gravity. Gravity pulls things down toward the ground (again, it's more complicated than that, but I'm trying to simplify).
Clearly, if the bird is up in the air, there must be another force to balance gravity or else the bird would accelerate downward and hit the ground. That force is generated by the shape of the bird's wings and is called lift. It creates a force directed straight upward, opposite gravity. Should the bird wish to go further up, it would need to generate more lift.
Now, we know that the bird could accelerate forward and go faster if it wanted to--that force, which is produced by the bird's wings, is called thrust. It is directed forward. But again, we said the bird was flying at a steady speed, which must mean that there is a fourth force acting on the bird which can balance thrust! We call that fourth force drag--you've probably heard of drag before; it's a result of friction between the air and the bird.
So, those are the four forces on a bird flying in still air. If we add wind speed to the equation, it's just like adding thrust--a force is pushing the bird in a certain direction, and it will accelerate until it is slowed and then balanced by drag. By the way, velocity is simply speed with a direction. So by 'wind velocity', someone means something like, '25 mph from the north-west'.
For a balloon, you need to think about the forces in the same way as we've just thought about them for a bird. Can a balloon produce thrust? Is there some force on it acting the way lift acts on a bird? If not, what would happen?
You also need to think about helium--what's different about this gas relative to 'normal' air? Might those differences create a force, which could impart an acceleration (=change in velocity) to a balloon?
That said, I study bird flight--so let me talk about the forces and how they work for a bird, and then you can think of how they might differ for a helium-filled balloon.
I apologize in advance if any of this is too simplistic for you; I'm not sure what your background is and what you will understand and what you won't.
Let's first consider a bird flying at some steady speed in zero wind.
Are you familiar with Newton's Laws? One of them states that force equals mass times acceleration. Acceleration is a change in speed through time--I'm sure you've experienced acceleration and deceleration (slowing down) in a car or on a bike. You can think of mass as weight; it's actually a little more complicated than that but I'm going to simplify as much as possible.
Now, you can apply multiple forces to an object; for example, you could push a trolley while someone else pulls on it. In that case, you add up all the forces and the result will equal mass times acceleration. If you are both pushing and pulling in the same direction, the trolley will accelerate in that direction. If you push one way and your friend pulls another, which way the trolley goes will depend on which force is greater and what direction the forces are applied in. If you are pushing/pulling in opposite directions with exactly the same force, it will go nowhere because the sum of the fores is zero. Make sense?
So let's go back to our bird, flying along. I said that it was flying at a steady speed, which means that it is /not/ accelerating (changing speed). This means that the sum of all the forces on it is zero.
The first obvious force that must be acting on it is gravity. Gravity pulls things down toward the ground (again, it's more complicated than that, but I'm trying to simplify).
Clearly, if the bird is up in the air, there must be another force to balance gravity or else the bird would accelerate downward and hit the ground. That force is generated by the shape of the bird's wings and is called lift. It creates a force directed straight upward, opposite gravity. Should the bird wish to go further up, it would need to generate more lift.
Now, we know that the bird could accelerate forward and go faster if it wanted to--that force, which is produced by the bird's wings, is called thrust. It is directed forward. But again, we said the bird was flying at a steady speed, which must mean that there is a fourth force acting on the bird which can balance thrust! We call that fourth force drag--you've probably heard of drag before; it's a result of friction between the air and the bird.
So, those are the four forces on a bird flying in still air. If we add wind speed to the equation, it's just like adding thrust--a force is pushing the bird in a certain direction, and it will accelerate until it is slowed and then balanced by drag. By the way, velocity is simply speed with a direction. So by 'wind velocity', someone means something like, '25 mph from the north-west'.
For a balloon, you need to think about the forces in the same way as we've just thought about them for a bird. Can a balloon produce thrust? Is there some force on it acting the way lift acts on a bird? If not, what would happen?
You also need to think about helium--what's different about this gas relative to 'normal' air? Might those differences create a force, which could impart an acceleration (=change in velocity) to a balloon?
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Craig_Bridge
- Former Expert
- Posts: 1297
- Joined: Mon Oct 16, 2006 11:47 am
This question has more to do with probability theory than with the physics involved in helium balloon flight. The probability of a helium balloon ending up in your garden. Some factors that affect the probability are:Why is it that I have never found a deflated one in my garden after a children's party?
1) How may balloons are released upwind of you. If there are none, then you wouldn't expect to find one.
2) How large an area is your garden compared to all of the potential areas where a balloon might end up?
3) What might or might not be present in your garden to trap a balloon? If there isn't anything to trap one, why would you expect it not to tumble along and find a more likely spot to end up.
As to the physics involved in lighter than air balloon, there are many factors involved, but fewer than heavier than air flight characteristics of birds.
1) Thermodynamics - gas pressure, temperature, density inside the balloon and outside and their effects on bouyancy.
2) Air currents (wind) and drag (shape factors that couple wind current into forces on the balloon) and mass.
-Craig
I think this is probably the correct reasoning to evaluate the question. Also, since you rarely _look_ for deflated balloons (or parts of balloons) you probably do not have an accurate observation. I mean, how often do you look at trash in the street carefully to identify what it is/where it came from?Craig_Bridge wrote:This question has more to do with probability theory than with the physics involved in helium balloon flight. The probability of a helium balloon ending up in your garden. Some factors that affect the probability are:Why is it that I have never found a deflated one in my garden after a children's party?
1) How may balloons are released upwind of you. If there are none, then you wouldn't expect to find one.
2) How large an area is your garden compared to all of the potential areas where a balloon might end up?
3) What might or might not be present in your garden to trap a balloon? If there isn't anything to trap one, why would you expect it not to tumble along and find a more likely spot to end up.
Louise