2-Measuring Matter (Mass)
Mass: The amount of matter in an
object is said to be its mass, but the common name is weight. To get the mass
of a solid, you would use direct measurement; where as if you where measuring a
liquid or gas,
you would have to use indirect measurement. The unit used to
record the mass of an object is grams. Milligrams are for the smallest
weight
(such as a pebble), grams for something about the mass of a medium
sized rock, kilograms for a larger weight, like a human body or an
aquarium, and tonnes for something quite heavier, like a car.
To get the mass of a solid, you weigh it on a scale that was
adjusted to the air pressure surrounding it, and the number that appeared on the scale would
be its mass. This is an example of direct measurement.
To measure a set amount of liquid, you would need to have a
scale with a container on top, and use a method indirect measurement. For
starters, set the scale to zero, and then place the container on top, and pour
the substance in. When you get the combined weight of the container and liquid,
subtract the mass of the container from the total, and you have the weight of
the set amount liquid. Another way is to find out the density and volume, and
multiply them together (DxV=M).
As for measuring the mass of a gas, there are three simple
ways; all using indirect measurement. The first way, (easiest), is to find out
the density from a reference book, and then multiply it by the volume of the
set amount (DxV=M). Another way is to put the gas into a container with
liquid and weight the original mass (L+C=oM), then weigh the added mass
of the gas, and subtract from the total; (L+C=oM;(L+C+G)-oM=M). The
third and final way of measuring a gas is to freeze/solidify it and measure it
before any evaporation occurs. Below is an image of a scale.