Science

[Weaverk53]

How do you determine Density?

[steveb]

it is mass per unit volume, divide mass by volume

[vascop]

so if it's a liquid you weigh it and put it in a measuring cylinder to get the volume.
If it's a solid you weigh it and then put it into a measuring cylinder of water and subtract the two readings to get the volume.
If it's a gas then the volume is easy because you put the gas into a vessel of known volume, For the mass it's not so easy to get an accurate answer as gases are so light.

There are various ingenious methods which you can find out about by searching on the internet.

[vascop]

Also remember that density varies with temperature, since with a given mass of anything, the volume changes as the temperature changes. This is especially significant with gases since they always fill whatever space is available.

Strictly speaking a density value should always be quoted together with the value of the temperature of the substance when the measurement was made.

[mibn2cweus]

Density might also vary with pressure, especially for gases.

Within a confined space, mass and volume, and therefore density, remain the same whereas temperature and pressure are mutually effected.

Where volume is not fixed, temperature and pressure have inverse effects on density:
greater temperature = lower density
greater pressure = greater density

Density of various substances are typically referenced to STP (standard temperature and pressure) conditions.

All gases have the same density as air under STP conditions.


Measuring Density

[mibn2cweus]

Ah oh! "All gases have the same density as air under STP conditions". Disregard that comment.

Density of a gas at STP varies with the molecular weight of the gas.

[Theland1]

Erm .... Mibs ..... Sanctuary ........

[Theland1]

Education divided by common sense = density.

[mibn2cweus]

measuring gas density and gas density formula