Carolyn N. Kinder
Matter is what the world is made of. All materials consist of matter. All matter has its own set of properties or characteristics. Some properties of matter such as color, size, and shape can be observed easily; other properties cannot be observed quite so easily. Properties that can be determined without changing the substance into a new kind of substance are called physical properties. Changes that do not produce a new kind of substance are called physical changes. During a physical change, the physical properties of a substance are altered, but the substance remains the same kind of matter.
Two Basic Properties: Mass and Volume
Mass is the most important physical property of matter in an object. The kilogram is the basic unit of mass in the metric system. For example, there is more matter in a large pool than in a child’s play pool. So a large pool has more mass than a child’s play pool. To measure small units of mass, we use the gram. One kilogram is equal to 1000 grams.
Volume is another important property of matter. Volume is the amount of space an object takes up. Volume is expressed in units called liters (1), milliliters (ml) and cubic centimeters (cm
3
). One liter is equivalent to 1000 cubic centimeters.
Using the two physical properties of mass and volume, you can define matter as anything that has mass and volume.
Density
Density is the mass per unit volume of a substance. The following formula can be used to find the density of an object. Density is mass/volume. Mass is usually expressed in grams, and volume in milliliters or cubic centimeters. Thus density is g/ml or g/cm
3
. So we can compute the density of a 1-centimeter cube taken from the planet Mars with a mass of 3.96 grams. The average density of mass would be: Density=3.96g (mass)/1 cm
3
(volume)=3.96 g/cm
3
. The density of water is 1g/cm
3
, while the density of gold is 19.32g/cm
3
.