3-Measuring Matter
(Volume and Density)
Volume: To get the volume of a solid or a liquid, you
go through steps similar to that of mass. It is possible to get the average
volume of a gas, even though a gas fills the container/area it is in (the gas
atoms/molecules have far bigger spaces between them than a solid or liquid, so
are not as compressed.) The units used to measure volume are milliliters, liters
and kiloliters.
To find the volume of a solid, you would use either of three
methods- Multiplying the mass by the density (MxD=V), or indirect
measurement with a liquid, similar to the way of getting the mass of a gas.
First, you would fill a beaker partially full with liquid, measure the volume,
and drop the solid in, and measure the volume again. Then, you subtract the
original volume form the total volume, and you would have the volume of that
liquid (TV(L+S)-Lv=Sv). Another way is that if the solid is cubic or rectangular,
like a CD case or a die, you multiply the length x width x height,
and end up with the volume (LxWxH=Mcm3).
To get the volume of a liquid, you would simply pour that
substance into a graduated cylinder and record the number that the meniscus is
at.
The only way to measure the volume of a gas is to measure
the volume of the container that it is in, so if you wanted to (for example)
get the volume of a filled up balloon, you would have to have a container
marked with the a liter unit. Putting that container upside down under-water or
completely filled up with a liquid, you'd slowly release the gas inside the
balloon into the container, you would get the volume by noting the numbers on
the side.
Density: when the mass of an object is divided into the volume, you end up with
X number of grams in one cm3, or the density (heaviness) of an object.
If an object’ s density is greater than 1g/cm3, it will sink in water,
for it is heavier. If it is less that 1g/cm3, then it will float on
water; for water’s density is 1g/cm3 (M over V(fraction), so V/M =
Dg/cm3).
Below are photos of a cube, a graduated cylinder, and wood floating in water.
1-Intro/Temperature 2-Measuring Mass
3-Measuring Volume/Measuring Density