Temperature is ultimately a measure of molecular movement. The higher the temperature, the more the molecules of a body agitate and move. Some bodies, such as gases, are ideal to observe the impact temperature changes has on bodies. Different temperatures alter the pressure, volume and even the physical state of the body.
Differences in molecular movement
Temperature is a measure of energy. The higher the energy, the higher the temperature. The energy absorbed by the molecules on a body make the molecules of the body agitate and move faster, in a chaotic way. Colder bodies have molecules that move slower with less chaos. Molecules in a solid can not move freely but they agitate faster.
Differences in Pressures
Pressure is directly related to temperature. This effect is best observed in in gases. At higher temperatures, molecules move faster, colliding more constantly with other bodies. This collisions increase pressure. Lower temperatures have the opposite effect. Molecules move slower, colliding less and reducing pressure.
Differences in Volume
Volume is also related to temperature. When a body increases its temperature it dilates. This increase in volume is caused by the increasing movement in molecules. The opposite effect, contraction, is observed in bodies as the temperature lowers. This property of changing volume is easily observed in some materials like metals.
Changes in State
As a body gets hotter and hotter, its energy rises and its molecules agitate more and more. At some point, the molecules use the extra heat to separate, triggering a change in aggregation state. The different states are also related to the effect of energy and heat on their molecules. The aggregation states from colder to hotter are solid, liquid and gas.