STD VIII – MATTER (Online)

Kinetic Theory of Matter.

Kinetic energy is the energy that is produced when an object is in motion. It is defined as the work required to accelerate a body from rest to a particular velocity. If an object is not moving, then the object is said to have zero kinetic energy.

The word kinetic comes from a Greek word, ‘kinesis’ meaning motion. Although theories about kinetic energy have been known from Aristotle’s time, physicists and scientists started experimenting with it only in the mid-19th century.

All things that move in the universe are said to possess kinetic energy. They can be large objects like planets, meteorites, lava, and a rubber call to the smallest of matter like atoms. An object with a heavier mass is said to move faster, hence it has more kinetic energy. Kinetic energy is dependent on the velocity and mass of an object.

Change of State

A change of state occurs whenever matter changes from one state to another. … They are reversible changes that do not change matter’s chemical makeup or chemical properties. Processes involved in changes of state include melting, freezing, sublimation, deposition, condensation, and evaporation