Physics is a branch of science concerned with the study of matter and its motion through space and time, along with how it relates to other concepts such as energy and force. Basically, matter is anything that occupies space and has got mass. Mass is measured as the quantity of matter in an object and its SI unit is grams.
States of Matter
Matter exists in three states namely; solids, liquids and gases. A solid refers to a tangible object with a definite shape, mass and volume whereas a liquid refers to a tangible object with no definite shape but has a definite volume. This means that liquids take the shape of the container in which they are put.
On the other hand, a gas refers to a substance with no definite shape and no definite volume. Gases are also intangible and invisible and their volumes are influenced by changes in temperature and pressure. As volumes are only stable under room temperature or pressure or under any other controlled conditions, upon which a slight variance in the two variables causes a proportionate change in its volume.
Changes In The States Of Matter
The three states of matter are not permanent but rather physical. Their existence depends on temperature variations. The following are the terms used to describe the various processes through which matter changes state.
Melting – this is the change if state from solid to liquid as is observed when an ice is placed on a hot pan.
Vaporization/Evaporation – this refers to the change of state from liquids to gases as is observed when water is heated.
Condensation – this is the change of state from a gaseous state to a liquid state, as is observed when water vapor cools in the clouds and forms rain.
Freezing – matter is said to be freezing if it changes state from liquids back to solids, an example is the phenomenon that takes place in our home refrigerators.
Sublimation –This is a direct change of state from solids to gases without necessarily passing through the liquid stage. An example of a substance that sublimes is iodine and most anhydrous compounds.
Other Things That Affect Matter
Aside from mass, volume, temperature and pressure, there are other concepts that are closely related to matter. These include force, weight, density and energy.
Force is the pull or push of an object and it is measured in Kilojoules. A man pulling a hand cart is an example of application of force. Weight refers to the gravitational pull of an object, as is observed on weighing scales.
Energy refers to the property of matter that can be transferred to other matter or converted into different forms which explains why energy at rest [potential energy] can be converted into energy in motion [kinetic energy]. Lastly, density refers to mass measured under unit volume.