What about a pressurized tank of helium? Heavier full of helium than empty?

What if you released the gas from the helium into a large balloon which was
attached to the helium tank. Would the balloon at some point lift the helium
tank once it was filled with helium from the tank?

According to Bill :
What about a pressurized tank of helium? Heavier full of helium than empty?

Define full. Define empty ;-)

A pressurized tank of gas isn't "full" until you fill it so much that
it turns to liquid. The pressures required (depending on the gas), of course,
often makes that impractical.

Empty? Do you mean that the tank is a vacuum? Or, full of air you have to
displace?

If by empty, you mean "vacuum", then of course, once you add _anything_
to the tank, the weight goes up.

If by empty, you mean full of air, and the adding of helium displaces air,
the weight will decrease until you displace all of the air, then it'll start
rising again.

What if you released the gas from the helium into a large balloon which was
attached to the helium tank. Would the balloon at some point lift the helium
tank once it was filled with helium from the tank?

Depends on the empty weight of the tank and how much helium was involved, but
yes, certainly, it could lift the empty tank.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

wrote:
On Thu, 27 Oct 2005 21:59:18 -0700, "Bill"
wrote:

What about a pressurized tank of helium? Heavier full of helium than
empty?

What if you released the gas from the helium into a large balloon
which was attached to the helium tank. Would the balloon at some
point lift the helium tank once it was filled with helium from the
tank?


Of course not, or the tank would float without the balloon......

Error.. If the balloon expanded enough so that it displaced enough air
that the weight of that air (air does have weight) was greater than the
weight of the tank and helium, then it would float.

Think of it this way. The full tank weighs more than an empty tank. If
you start filling balloons and tie each one onto the tank, each one will try
to lift the tank. As the tank is emptied it gets lighter and there are more
balloons trying to lift it. Get enough of the them and the tank will be
lifted.


Mark

--
Joseph Meehan

Dia duit

"Bill" wrote in message
...
What about a pressurized tank of helium? Heavier full of helium than
empty?

Yes, true with any compressed gas

What if you released the gas from the helium into a large balloon which
was attached to the helium tank. Would the balloon at some point lift the
helium tank once it was filled with helium from the tank?

Sure. In the tank it is compressed. In the balloon, it is expanded and
displacing heavier air so it will lift.

wrote in message
news
On Thu, 27 Oct 2005 21:59:18 -0700, "Bill"

wrote:

What about a pressurized tank of helium? Heavier full of
helium than empty?

What if you released the gas from the helium into a large
balloon which was
attached to the helium tank. Would the balloon at some
point lift the helium
tank once it was filled with helium from the tank?


Of course not, or the tank would float without the
balloon......

LOL!!

Bob

What if you released the gas from the helium into a large balloon which
was attached to the helium tank. Would the balloon at some point lift the
helium tank once it was filled with helium from the tank?

Sure. In the tank it is compressed. In the balloon, it is expanded and
displacing heavier air so it will lift.

The balloon will lift, but the question was could the balloons lift the
tank. Obviously depends on how much helium was in the tank, and how
much the tank weighs.

According to Larry Bud :
What if you released the gas from the helium into a large balloon which
was attached to the helium tank. Would the balloon at some point lift the
helium tank once it was filled with helium from the tank?

Sure. In the tank it is compressed. In the balloon, it is expanded and
displacing heavier air so it will lift.

The balloon will lift, but the question was could the balloons lift the
tank. Obviously depends on how much helium was in the tank, and how
much the tank weighs.

And atmospheric pressure and...

Indeed, you can fill a balloon[+] with the contents of an _empty_ tank[*] and have it
lift the empty tank. ;-)
[*] An empty tank contains vacuum.
[+] okay, okay, a _rigid_ balloon.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

According to :

Now, as if this thread was not already crazy enough, I got to
thinking.
If a person fills all the tires on their car with helium instead of
air, will the car be lighter on the ground and save fuel? (((Just a
thought))). Obviously the car would not float because it's too haevy
and there is not enough helium. If this worked at all, it would not
be a good idea in winter when weight is needed for traction on snow
and ice.

The car would be lighter by a few ounces or so - the economies of doing
this would be too small to be measurable. Helium ain't exactly
cheap either.

Of course if you filled the whole car with helium (after seriously
plugging all the leaks), would the car fly?

A few dozen cubic feet of helium won't lift a person, let alone
several thousand pounds of car.

This would not be a good
idea though because the driver would be talking like tweety bird on
his cell phone before he died a couple minutes later from lack of
oxygen..

Well, he could use a scuba tank, or an external air scoop ;-)
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

wrote:

I guess thats bcause its not compressed any longer, huh?

Now, as if this thread was not already crazy enough, I got to
thinking.
If a person fills all the tires on their car with helium instead of
air, will the car be lighter on the ground and save fuel? (((Just a
thought))). Obviously the car would not float because it's too haevy
and there is not enough helium. If this worked at all, it would not
be a good idea in winter when weight is needed for traction on snow
and ice.

Unless you were driving a monster truck with REALLY big tires it
wouldn't change the weight of your car by more than a pound, so it
wouldn't really make a difference. Plus the helium would probably leak
out of your tires more quickly.

Of course if you filled the whole car with helium (after seriously
plugging all the leaks), would the car fly? This would not be a good
idea though because the driver would be talking like tweety bird on
his cell phone before he died a couple minutes later from lack of
oxygen..

For every cubic meter of air replaced with helium you get a whopping 2
or so pounds of lift. The average car probably has about 2-4 cubic
meters of passenger and cargo space so again not a very appreciable
gain there. Think about how large the Goodyear blimp needs to be to
hold up that little passenger cabin.

wrote in message

Of course if you filled the whole car with helium (after
seriously
plugging all the leaks), would the car fly? This would
not be a good
idea though because the driver would be talking like
tweety bird on
his cell phone before he died a couple minutes later from
lack of
oxygen..

The car would get lighter by the difference in weight
between the car's volume in air and the car's volume in
helium. That's not much.

Bob

Of course if you filled the whole car with helium (after seriously
plugging all the leaks), would the car fly? This would not be a good
idea though because the driver would be talking like tweety bird on
his cell phone before he died a couple minutes later from lack of
oxygen..


I forget why, but I have stuck in my head that an order-of-magnitude
estimate for the lift of STP helium is around 1 pound per cubic yard,
displacement.

This just keeps getting more and more interesting !!!!

Mark

wrote:
On Fri, 28 Oct 2005 11:25:34 GMT, "Joseph Meehan"
wrote:

wrote:
On Thu, 27 Oct 2005 21:59:18 -0700, "Bill"
wrote:

What about a pressurized tank of helium? Heavier full of helium than
empty?

What if you released the gas from the helium into a large balloon
which was attached to the helium tank. Would the balloon at some
point lift the helium tank once it was filled with helium from the
tank?


Of course not, or the tank would float without the balloon......

Error.. If the balloon expanded enough so that it displaced
enough air that the weight of that air (air does have weight) was
greater than the weight of the tank and helium, then it would float.

Think of it this way. The full tank weighs more than an empty
tank. If you start filling balloons and tie each one onto the tank,
each one will try to lift the tank. As the tank is emptied it gets
lighter and there are more balloons trying to lift it. Get enough of
the them and the tank will be lifted.


Mark

That's weird......
I guess thats bcause its not compressed any longer, huh?

Indirectly yes. When it is contained, but under less pressure it will
take up more space, displacing more air and like a boat it will float.


Now, as if this thread was not already crazy enough, I got to
thinking.
If a person fills all the tires on their car with helium instead of
air, will the car be lighter on the ground and save fuel? (((Just a
thought))). Obviously the car would not float because it's too haevy
and there is not enough helium. If this worked at all, it would not
be a good idea in winter when weight is needed for traction on snow
and ice.

Yea, it likely would be lighter (some uncertainty because I don't recall
how helium acts under pressure, if it were to compress sufficiency more than
air, it might not be lighter, but I really don't think that is an issue.
However it might be a few ounces lighter, not enough to worry about.


Of course if you filled the whole car with helium (after seriously
plugging all the leaks), would the car fly?

Not even if you could create a perfect vacuum (which would be even
lighter than helium. The car would still weigh far more than the air it
displaces.


This would not be a good
idea though because the driver would be talking like tweety bird on
his cell phone before he died a couple minutes later from lack of
oxygen..

This just keeps getting more and more interesting !!!!

Mark

--
Joseph Meehan

Dia duit

Bill wrote:
What about a pressurized tank of helium? Heavier full of helium than empty?

What if you released the gas from the helium into a large balloon which was
attached to the helium tank. Would the balloon at some point lift the helium
tank once it was filled with helium from the tank?


Empty is a relative term. A tankful of helium at
1 atm is lighter than a tankful of air at 1 atm.

Of course if you release helium into a large
balloon at some point it will lift the tank of
compressed helium.

It's all about floating; floating in air is the
same principle as floating in water. Basically if
an object weighs less than surrounding gas or
liquid weighs, it will float. For example as
soon as the balloon inflates, it gets larger and
displaces more air. As soon as the volume is
large enough that the weight of air it displaces
slightly exceeds the weight of the balloon, the
internal helium gas, and everything attached to
it, it will start to float.

Larry Bud wrote:
What if you released the gas from the helium into a large balloon which
was attached to the helium tank. Would the balloon at some point lift the
helium tank once it was filled with helium from the tank?

Sure. In the tank it is compressed. In the balloon, it is expanded and
displacing heavier air so it will lift.


The balloon will lift, but the question was could the balloons lift the
tank. Obviously depends on how much helium was in the tank, and how
much the tank weighs.


Actually the primary factor after the weight of
the tank and other equipment is the volume of air
that the balloon displaces.

On Fri, 28 Oct 2005 20:34:14 -0000, (Chris
Lewis) wrote:


Of course if you filled the whole car with helium (after seriously
plugging all the leaks), would the car fly?

A few dozen cubic feet of helium won't lift a person, let alone
several thousand pounds of car.

Ask the guy in the lawn chair with the balloons and the bb-gun. He
khnows all about how much helium is needed.

Remove NOPSAM to email me. Please let
me know if you have posted also.

mm wrote:
On Fri, 28 Oct 2005 20:34:14 -0000, (Chris
Lewis) wrote:


Of course if you filled the whole car with helium (after seriously
plugging all the leaks), would the car fly?

A few dozen cubic feet of helium won't lift a person, let alone
several thousand pounds of car.

Ask the guy in the lawn chair with the balloons and the bb-gun. He
khnows all about how much helium is needed.

The Myth Busters did that one and it took hundreds of very large
balloons to lift a small child. You man in the lawn chair was proven a
myth.


Remove NOPSAM to email me. Please let
me know if you have posted also.

--
Joseph Meehan

Dia duit

On Sun, 30 Oct 2005 18:24:43 GMT, Tom Quackenbush
wrote:


I didn't see that show - what size balloons were they using? The
references I've seen to Lawnchair Larry all say that he was using 40 +
weather balloons. I don't know what size his balloons were, but it
seems like 40 6-8' weather balloons would be plenty to lift an adult
male.

http://www.snopes.com/travel/airline/walters.asp

Wow. I certainly didn't know all these details. Thanks

He spent 110 dollars for the lawn chair. I assume it was made from
aluminum. I didn't realize one could spend that much for an aluminum
chair, but when you're going to 15,000 feet, it's worth the extra 95
dollars.

I didn't hear about this on the internet, which didn't exist then. I
read it in the paper. I'm sorry thinkgs didn't turn out well for
Larry. he had more imagination and courage than I do.

Do you think that the FAA didn't really fine Walters or Walsh?

R,
Tom Q.


Remove NOPSAM to email me. Please let
me know if you have posted also.

Tom Quackenbush wrote:
Joseph Meehan wrote:
mm wrote:
snip
Ask the guy in the lawn chair with the balloons and the bb-gun. He
khnows all about how much helium is needed.

The Myth Busters did that one and it took hundreds of very large
balloons to lift a small child. You man in the lawn chair was
proven a myth.

I didn't see that show - what size balloons were they using? The
references I've seen to Lawnchair Larry all say that he was using 40 +
weather balloons. I don't know what size his balloons were, but it
seems like 40 6-8' weather balloons would be plenty to lift an adult
male.

I don't remember the size, but it was on Pilot #3 episode.


http://www.snopes.com/travel/airline/walters.asp

Do you think that the FAA didn't really fine Walters or Walsh?

R,
Tom Q.

--
Joseph Meehan

Dia duit

Absolutely, WRONG!

The answer is explained better by an understanding of basic physics of
density, than doing a google search.

The tank is full of COMPRESSED helium. It's density per unit volume is much
higher than the helium in a balloon. The balloon floats because of the
differential of densities between AIR & HELIUM.

It is NOT the same scenario in the tyre, since we are dealing with the same
gases, in the same reference frame. The tyre contains air at a higher
density than the air in the frame of reference (around the tyre). Therefore
it has MORE MASS when filled, than empty.


wrote in message
news
On Thu, 27 Oct 2005 21:59:18 -0700, "Bill"
wrote:

What about a pressurized tank of helium? Heavier full of helium than
empty?

What if you released the gas from the helium into a large balloon which
was
attached to the helium tank. Would the balloon at some point lift the
helium
tank once it was filled with helium from the tank?


Of course not, or the tank would float without the balloon......

Mark