Does the Weight of an Airplane and Contents Change?

Alan Bell wrote:
after we eat, the same as when the plane took off? And what about two hours
after we eat? When nature takes it course, is the aggregate weight still the
same?

Overall, you sweat or exhale a lot of the water contents of the food you
eat/drink, and that humidity is dumped overboard as the air is replaced in the cabin.

The E = MC2 aspect would probably be so small that it wouldn't matter with
regards to mass converted to energy by muscles.

Flying back to LA from DC this weekend, I got to wondering about something
stupid. I have no idea who to ask, so I thought I'd see if anyone here had a
clue.

When we get on the plane, there are a certain number of people and a certain
amount of food. During the five hours we are in the air, we eat food and
drink beverages. Eventually the trays of food and the soft drink cans are
empty. They weigh less. We have food and drink in our stomachs. Do we now
weigh more? Is the combined weight of the airplane and everything in it
after we eat, the same as when the plane took off? And what about two hours
after we eat? When nature takes it course, is the aggregate weight still the
same?

Alan Bell wrote:
Flying back to LA from DC this weekend, I got to wondering about something
stupid. I have no idea who to ask, so I thought I'd see if anyone here had a
clue.

When we get on the plane, there are a certain number of people and a certain
amount of food. During the five hours we are in the air, we eat food and
drink beverages. Eventually the trays of food and the soft drink cans are
empty. They weigh less. We have food and drink in our stomachs. Do we now
weigh more? Is the combined weight of the airplane and everything in it
after we eat, the same as when the plane took off? And what about two hours
after we eat? When nature takes it course, is the aggregate weight still the
same?


Well, the plane would weigh less because the fuel would have been burnt
and byproducts of this would have left the plane.

As far as the food, etc refer to the Law of Conservation of Mass:
Matter can not be created or destroyed. So, unless it finds a way off
the aircraft, it would still be on the aircraft.

The weight will be less since there will be fuel expended. FFM

Alan Bell wrote:

Flying back to LA from DC this weekend, I got to wondering about something
stupid. I have no idea who to ask, so I thought I'd see if anyone here had a
clue.

When we get on the plane, there are a certain number of people and a certain
amount of food. During the five hours we are in the air, we eat food and
drink beverages. Eventually the trays of food and the soft drink cans are
empty. They weigh less. We have food and drink in our stomachs. Do we now
weigh more? Is the combined weight of the airplane and everything in it
after we eat, the same as when the plane took off? And what about two hours
after we eat? When nature takes it course, is the aggregate weight still the
same?

"mtravelkay" wrote in message
om...
Alan Bell wrote:
Flying back to LA from DC this weekend, I got to wondering about
something
stupid. I have no idea who to ask, so I thought I'd see if anyone here
had a
clue.

When we get on the plane, there are a certain number of people and a
certain
amount of food. During the five hours we are in the air, we eat food and
drink beverages. Eventually the trays of food and the soft drink cans
are
empty. They weigh less. We have food and drink in our stomachs. Do we
now
weigh more? Is the combined weight of the airplane and everything in it
after we eat, the same as when the plane took off? And what about two
hours
after we eat? When nature takes it course, is the aggregate weight still
the
same?


Well, the plane would weigh less because the fuel would have been burnt
and byproducts of this would have left the plane.

As far as the food, etc refer to the Law of Conservation of Mass:
Matter can not be created or destroyed. So, unless it finds a way off
the aircraft, it would still be on the aircraft.

Blue Ice meteors. You hear about them once in a while. Fact or fiction?

Yes, I understand that. But the expenditure of jet fuel wasn't the thrust of
my question and I take responsibility for writing my question wrong. I
should have written: "Is the combined weight of the people, the food, the
food containers, the waste facilities and the air we breathe -- I'm trying
to think of everything related to the passengers, the food and its
consumption -- constant over the course of the flight?

"Frank F. Matthews" wrote in message
...
The weight will be less since there will be fuel expended. FFM

E=mc2 - refers to energy creation and destruction of matter - as in a
nuclear or thermo-nuclear reaction. Nothing to do with the energy
transformations which occur in the human body!!

The aircraft would weigh exactly what it did on take-off MINUS the weight of
water lost in air exchange, fuel burnt and waste matter jettisoned through
the toilet and waste water systems.


"nobody" wrote in message
...
Alan Bell wrote:
after we eat, the same as when the plane took off? And what about two
hours
after we eat? When nature takes it course, is the aggregate weight still
the
same?

Overall, you sweat or exhale a lot of the water contents of the food you
eat/drink, and that humidity is dumped overboard as the air is replaced in
the cabin.

The E = MC2 aspect would probably be so small that it wouldn't matter with
regards to mass converted to energy by muscles.

freeda wrote:
Is excrement not jettisoned overboard? We have all heard stories of frozen
turds crashing through roofs.

Nop. Toilet system is self contained. Any dumping is due to malfunction of system.

The only stuff leaving aircraft during flight is humidity in the air. However,
if you give each passenger 1.5 litres of liquids during a flight, you can
expect a good portion of this to be dumped into cabin air (the other part as
urine and excrement).

On a 10 hours flight, you are supposed to drink 2 litres of water. That is 2
kilos. Assuming half of it goes into the air, if you have 400 pax, that would
be 400 kilos dumped overboard during flight. Yes, it is peanuts compared to
tonnes of fuel that leave the aircraft.

Many airlines have outfitted their crew rests with humidifiers. The water for
those is dumped overboard as humidity. Not sure how much water is involved.

Where the equation becomes less accurate is that you can't measure how much
water/food is already in passengers when they board aircraft. Urine/excrement
may not come from food/liquids consumed aboard aircraft, so if you try to
calculate the weight of the waste water emptied at destination airport versus
weight of food/drinks dispensed during flight, it may not represent totally
accurate picture.

To put things in perspective, in australian desert, a cyclist can consume well
above 10 litres of water per day and urinate only a very small portion of
this, the rest all gone through perspiration. People usually underestimate the
amount of water they consume in any given day.

Alan Bell wrote:
Flying back to LA from DC this weekend, I got to wondering about something
stupid. I have no idea who to ask, so I thought I'd see if anyone here had a
clue.

When we get on the plane, there are a certain number of people and a certain
amount of food. During the five hours we are in the air, we eat food and
drink beverages. Eventually the trays of food and the soft drink cans are
empty. They weigh less. We have food and drink in our stomachs. Do we now
weigh more? Is the combined weight of the airplane and everything in it
after we eat, the same as when the plane took off? And what about two hours
after we eat? When nature takes it course, is the aggregate weight still the
same?



The weight lost from perspiration and the passengers burning calories is
insignificant. Consider that a plane burns a few thousand pounds of fuel
per hour, then even if you had each person managing to burn a pound of
energy sustaining themselves on the flight (a generous guesstimate) on a
747 you'd come in ~400 lbs less at landing than takeoff. No biggie.

ender wrote:

The weight lost from perspiration and the passengers burning calories is
insignificant. Consider that a plane burns a few thousand pounds of fuel
per hour, then even if you had each person managing to burn a pound of
energy sustaining themselves on the flight (a generous guesstimate) on a
747 you'd come in ~400 lbs less at landing than takeoff. No biggie.

And that would assume the pound used to sustain themselves left the
plane. After all, if you lose a pound, it doesn't disappear, it goes
someplace.