Thread: Mass and Volume ... PLeeEase HELP!

Ok... can somebody please help me here!

I am not a student of Physics but I am trying to get the simple idea that Mass and Volume are separate to each other.

I need a VERY simple example.

I keep picturing an orange. When I fill it with juice... I picture that to be it's volume.

So I'm thinking that the volume of an object creates it's mass... but then this confused me:

"... The term "volume" refers to the amount of space an object occupies..."

Because if I'm picturing volume as being a substance inside an object and attributing to it's mass... then why is this saying that the Volume is actually the object?

I know I'm interpreting something incorrectly here and it's driving me nuts!

I'd really appreciate proper answers and not cheeky ones about looking on Wikipedia!!

Thanks

Originally Posted by Janey

Ok... can somebody please help me here!

I am not a student of Physics but I am trying to get the simple idea that Mass and Volume are separate to each other.

I need a VERY simple example.

I keep picturing an orange. When I fill it with juice... I picture that to be it's volume.

So I'm thinking that the volume of an object creates it's mass... but then this confused me:

"... The term "volume" refers to the amount of space an object occupies..."

Because if I'm picturing volume as being a substance inside an object and attributing to it's mass... then why is this saying that the Volume is actually the object?

I know I'm interpreting something incorrectly here and it's driving me nuts!

I'd really appreciate proper answers and not cheeky ones about looking on Wikipedia!!

Thanks

Take a graduated cylinder partially filled with water. Now take an object and push it under the surface of the water. The change in the level of the water in the cylinder is a mesure of the volume of the object.


Now take the object and place it on a scale. The weight of the object is a measure of the mass. It is the force on the object as a result of gravitationlal attraction from the earth and is proportional to mass, the proportionality constant being 9.8 Newtons per kilogram.

Take a graduated cylinder partially filled with water. Now take an object and push it under the surface of the water. The change in the level of the water in the cylinder is a mesure of the volume of the object.


Now take the object and place it on a scale. The weight of the object is a measure of the mass. It is the force on the object as a result of gravitationlal attraction from the earth and is proportional to mass, the proportionality constant being 9.8 Newtons per kilogram.

So, basically... Volume is not what's IN the object... what's in the object (along with gravity) results in it's Mass.

What's AROUND the object is it's Volume. Its a measure of how much space it occupies.

Is this correct?

generally speaking, yes. Volume would be the amount of space it occupies where mass is the amount of 'stuff' you have in there.

Originally Posted by Janey

Take a graduated cylinder partially filled with water. Now take an object and push it under the surface of the water. The change in the level of the water in the cylinder is a mesure of the volume of the object.


Now take the object and place it on a scale. The weight of the object is a measure of the mass. It is the force on the object as a result of gravitationlal attraction from the earth and is proportional to mass, the proportionality constant being 9.8 Newtons per kilogram.

So, basically... Volume is not what's IN the object... what's in the object (along with gravity) results in it's Mass.

What's AROUND the object is it's Volume. Its a measure of how much space it occupies.

Is this correct?

Volume is precisely the amount of space that it occupies.

Mass exists without gravity, and is roughly speaking, the amount of "stuff" that is in the object. The force of gravity acts on mass and the resulting force is weight. Weight is proportional to mass, at the surface of the earth.

Thank You so much...

Volume makes sense to me now. (And Mass too!)
I may not understand it to the fullest as of yet, but at least I have the basics for now.

I'm sure I'll be back here for more answers in the future.

Thanks Again

I'll try my hand at explaining it. Essentially, volume is a measure of substance. Density is a constant, thirty m^3 of a circle's volume is equal to thirty m^3 of a square's volume. Now, here's the difference between mass and voloume: while all volume is the same, different substances don't have as much mass per cubic length as others. Thus, we have to multiply the density of something by its volume to find its mass. If all density was equal to one kilogram per cubic meter, than we could simply ignore it, as volume = mass. One final note: if object A has thirty percent greater density than object B, than object B would need to have thirty percent greater volume than object A, and vice versa.

EDIT: I apologise, I haven't read previous posts until now. One comment however:
mass is not how much "stuff that's within something," (although volume is the amount of stuff) but the product of how much stuff and the amount of stuff within the object.

Also another comment Janey, density and gravity don't result in mass. Density and volume do, and weight is little more than the downward net force of an object. We can find it simply using Newton's second law of motion: multiplying an object's mass by its acceleration (that is, the acceleration of the planet or whatever it may be it resides in). On Earth, everythings weight is about 980% greater than its mass.