[LiamS]

could anybody tell me:
the weights of fresh and salt water (in kg please)
how too calculate buoyancy
how too calculate the volume of water (at any temperature)


i have nothing else better too do =[ may as well keep the old noggin ticking over



cheers in advanced

 

[weazelz]

the weights of fresh and salt water (in kg please)

a kilo of salt water & fresh water weighs the same

 

[LiamS]

a kilo of salt water & fresh water weighs the same

i was sure there was a difference (albeit very small?)

due to the salt content?

 

[weazelz]

i was sure there was a difference (albeit very small?)

due to the salt content?

nope, a kilo of each weighs exactly the same

 

[Leg Of Salmon]

Learn to spell first, maths is too hard.


PS You lose!

 

[KenLorp]

The difference is in the volume.

Another way to think about it is this ... 1L of fresh water does not weight the same as 1L of seawater.

K.

i was sure there was a difference (albeit very small?)

due to the salt content?

 

[bubbleless]

How will it keep your brain going if I tell you how to do it??

You have been expected to get an A+ gcse??

Water is 1 gram per cubic centimetre

Buoyancy is to do with the mass of an object and the amount of water it displaces .

Archimedes Eureka!!!

Next Google is your Friend.....

 

[LiamS]

nope, a kilo of each weighs exactly the same

whoops sorry i meant how much a litre of each weighs

 

[LiamS]

How will it keep your brain going if I tell you how to do it??

You have been expected to get an A+ gcse??

Water is 1 gram per cubic centimetre

Buoyancy is to do with the mass of an object and the amount of water it displaces .

Archimedes Eureka!!!

Next Google is your Friend.....

because once i know those i can go do the harder questions on the internet

i understand the Archimedes principle

if the object displaces a higher density of water than itself it is positively buoyant ect

 

[teddybeardiver]

Google is definitely your friend....

how much does a litre of water weigh - Google Search

how much does a litre of salt water weigh - Google Search=

 

[Lazlo]

(P1 * V1) / T1 = (P2 * V2) / T2

P = Pressure in bar absolute. Sea level = 1 bar absolute
V = Volume in Litres
T = Temperature in Kelvin

Resultant Buoyancy = force upwards (displaced water) - force downwards (gravity)

Fresh water is 1 kg/litre
Sea water = 1.03 kg/litre (ish)

The rest you can work out for yourself

 

[LiamS]

(P1 * V1) / T1 = (P2 * V2) / T2

P = Pressure in bar absolute. Sea level = 1 bar absolute
V = Volume in Litres
T = Temperature in Kelvin

Reslutant Buoyancy = force upwards (displaced water) - force downwards (gravity)

Fresh water is 1 kg/litre
Sea water = 1.03 kg/litre (ish)

The rest you can work out for yourself

cheers

if you smell smoke... it'll be me

 

[weazelz]

(P1 * V1) / T1 = (P2 * V2) / T2

P = Pressure in bar absolute. Sea level = 1 bar absolute
V = Volume in Litres
T = Temperature in Kelvin

this is the combined *gas* law - doesn't work very well for liquids

 

[LiamS]

this is the combined *gas* law - doesn't work very well for liquids

Salt water weighs approx 8.55 lbs per gallon and fresh water weighs approx. 8.34 lbs per gallon

so now i can start doing lift bag physics ect???



i need a job :sad:

 

[362436]

Density= mass/volume

Fresh water is less dense than salt water (because of the salt dissolved in the latter!) ie it has a lower density. This makes you more buoyant in salt water since a given volume of salt water can support a greater weight of you than the same volume of fresh water.




P1 V1 /T1 = P2 V2 /T2 is the combined gas law

P1 V1 = P2 V2 is Boyle's Law (applying to an ideal gas at constant temperature)

 

[Dyson Diver]

beg borrow or steal a copy of the dm course work , it will explain most of what you want , in prob enough detail . encyclopedia of diving isnt bad , and the course workbook is usefull. without going to the expense of actually doing the course.
or
do the course.

 

[Lazlo]

this is the combined *gas* law - doesn't work very well for liquids

But is sometimes useful in buoyancy problems involving lift bags...

Admittedly including temperature could be considered overkill.

 

[Lazlo]

beg borrow or steal a copy of the dm course work , it will explain most of what you want , in prob enough detail . encyclopedia of diving isnt bad , and the course workbook is usefull. without going to the expense of actually doing the course.
or
do the course.

The PADI Encyclopedia of Recreational Diving is a brilliant book.

 

[weazelz]

But is sometimes useful in buoyancy problems involving lift bags...

Admittedly including temperature could be considered overkill.

ah, fair do's. didn't want liam wondering why his kettle doesn't explode when it boils

 

[Dyson Diver]

The PADI Encyclopedia of Recreational Diving is a brilliant book.

thats the one ,,, couple it with dm work book , should be enough knowledge for most , without turning pro.