How much should 500ml of water weigh ?
Discussion
tampon said:
She has a can of aerosol spray that is advertised at 500ml, and the can weighs 485 grams without the lid ( they all do, so it is not just one can that has been used ), so she has been undersold hasn't she.
sleep envy's right. if the aerosol sprayed pure water, then 500ml -> 500g. If it sprayed a lighter substance, 500ml could weigh pretty much anything. The 500ml will refer to the final volume of the substance that it sprays out (I think), so it could contain 500ml of air, which weighs close to nothing (I'm sure someone can actually work that out).
sleep envy said:
megy said:
sheepy said:
Related question, (and in the spirit of recycling): How much would a litre of petrol weigh? (Assuming room temperature, constant gravity of 9.81m/s etc)
Depending on the specific gravity of the petrol, which is around the 0.8 mark, it would have a weight of 0.8kg
depends on the type of petrol, F1 fuel has a mass of approx 850g/l
Exactly why i said it depends on the specific gravity of the petrol
megy said:
sleep envy said:
megy said:
sheepy said:
Related question, (and in the spirit of recycling): How much would a litre of petrol weigh? (Assuming room temperature, constant gravity of 9.81m/s etc)
Depending on the specific gravity of the petrol, which is around the 0.8 mark, it would have a weight of 0.8kg
depends on the type of petrol, F1 fuel has a mass of approx 850g/l
Exactly why i said it depends on the specific gravity of the petrol
yep
tampon said:
She has a can of aerosol spray that is advertised at 500ml, and the can weighs 485 grams without the lid ( they all do, so it is not just one can that has been used ), so she has been undersold hasn't she.
There's a simple way of testing this out. Get your friend to weigh her head, then spray the entire contents of the aerosol into her hair; a second weighing of her head will give you an accurate measure of the weight of the contents of the can. The second part of the test involves puffer fish, due to their elastic bellies: take a second can and spray its contents into the mouth of a puffer fish (you will probably need more than one). Drop the inflated fish into a bathtub of Ribena that you have previously gradated for volume (it's better to use coloured liquid as then it's easier to see the liquid against the gradations) and mark how much volume increase they add to the bath. So, if the increase in weight of her head is less than 500g, and the volume of the puffer fish is less than 500ml, then yes, she has been undersold and she should immediately take the bathtub and her head to some kind of consumer watchdog, AEROWAT or something, to expose this scandal.
Ecks Ridgehead said:
There's a simple way of testing this out. Get your friend to weigh her head, then spray the entire contents of the aerosol into her hair; a second weighing of her head will give you an accurate measure of the weight of the contents of the can. The second part of the test involves puffer fish, due to their elastic bellies: take a second can and spray its contents into the mouth of a puffer fish (you will probably need more than one). Drop the inflated fish into a bathtub of Ribena that you have previously gradated for volume (it's better to use coloured liquid as then it's easier to see the liquid against the gradations) and mark how much volume increase they add to the bath. So, if the increase in weight of her head is less than 500g, and the volume of the puffer fish is less than 500ml, then yes, she has been undersold and she should immediately take the bathtub and her head to some kind of consumer watchdog, AEROWAT or something, to expose this scandal.
tampon said:
sleep envy said:
tampon said:
aerosol spray
as always the clue is in the question
does this aerosol contain solely water?
No it is a fabric protector spray, would that make a difference, could a 500ml spray weigh less than than 0.5kg ?
all fluids have different mass/ml
just like metals - e.g. lead has a diff mass/cm3 to aluminium
tampon said:
sleep envy said:
tampon said:
aerosol spray
as always the clue is in the question
does this aerosol contain solely water?
No it is a fabric protector spray, would that make a difference, could a 500ml spray weigh less than than 0.5kg ?
Are you winding us up?
It depends what is being sprayed. Water has a mass of 1kg per litre. Air is much lighter so 500ml of air would have much less mass. 500ml of fabric protector spray is probably mostly propellant (butane perhaps
) and will have very little mass. Edited by ewenm on Monday 15th January 15:58
tampon said:
sleep envy said:
tampon said:
aerosol spray
as always the clue is in the question
does this aerosol contain solely water?
No it is a fabric protector spray, would that make a difference, could a 500ml spray weigh less than than 0.5kg ?
As the other posters have said,it all depends what's in the spray.If the stuff is less dense than water then 500ml will weigh less than 500 grammes.
FunkyGibbon said:
Pickled Piper said:
I litre of water has a mass of 1kg always because that is how a litre is defined.
pp
pp
yep
"a metric unit of capacity equal to the volume of 1 kilogram of pure water at 4 degrees centigrade and 760 mm of mercury"
Nope actually (perhaps your reference is out of date). It's a unit of volume and its definition is therefore based on the definition for a metre - which is in turn defined by the distance travelled by light in vacuum during a certain time. Time is in turn defined by a number of periods of radiation (light) corresponding to transition between hyperfine levels of the ground state of a caesium atom. Begs the question of why a metre is not defined as a number of wavelengths of such radiation but who knows?
Edited by tybalt on Monday 15th January 16:10
sleep envy said:
how does pressure change mass? I thought mass stays the same and weight changes?
Right I think a few wires are being crossed - the higher the pressure the more "stuff" per cubic centimetre. Hence a gas will have a greater "mass" if the "pressure" is increased (and volume remains constant; as there is more of the gas molecules within the volume)
More mass equals more "stuff" for gravity to act upon (keeping volume constant) hence more weight.
Jinx said:
sleep envy said:
how does pressure change mass? I thought mass stays the same and weight changes?
Right I think a few wires are being crossed - the higher the pressure the more "stuff" per cubic centimetre. Hence a gas will have a greater "mass" if the "pressure" is increased (and volume remains constant; as there is more of the gas molecules within the volume)
More mass equals more "stuff" for gravity to act upon (keeping volume constant) hence more weight.
gotcha!
cheers jinx
zaktoo said:
and obviously, if the stuff in the can is pressurised, 500ml of the stuff would have a greater mass than 500ml of the same stuff unpressurised.
the mass of 'stuff' will be the same, regardless of pressure/volume. Volume will change with pressure change but the mass remains constant. (This is why the fuel quantity carried by an aircraft is measured by weight and not volume...)
JonRB said:
I'm sure that OrgasmicLiving will be along shortly to explain why it is not 500g and that it won't take off even if thrown forcefully against his head via a high-speed conveyor belt, but the fact of the matter is that 1L of water at room temperature and pressure (RTP) masses 1kg which in normal earth gravity means it weighs approx 1kg.
JuniorD said:
zaktoo said:
and obviously, if the stuff in the can is pressurised, 500ml of the stuff would have a greater mass than 500ml of the same stuff unpressurised.
the mass of 'stuff' will be the same, regardless of pressure/volume. Volume will change with pressure change but the mass remains constant. (This is why the fuel quantity carried by an aircraft is measured by weight and not volume...)
I don't mean 500ml of the "stuff" which is then compressed. I mean 500ml of compressed stuff. I know it isn't very clear from my original statement, apologies ;-)
Jinx said:
sleep envy said:
how does pressure change mass? I thought mass stays the same and weight changes?
Right I think a few wires are being crossed - the higher the pressure the more "stuff" per cubic centimetre. Hence a gas will have a greater "mass" if the "pressure" is increased (and volume remains constant; as there is more of the gas molecules within the volume)
It should be:
"Hence a gas will have a greater 'DENSITY' if the 'pressure' is increased as the volume is DECREASED. MASS remains constant as the number of gas molecules will be unchanged".
Edited by JuniorD on Monday 15th January 16:49
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