The best answer is: Because heat has been transferred
to the substance, and it now contains more of it.
temperature goes up when gas is forced to change into a liquid. The amount the temperature goes up is related to the "heat of vaporization" of the particular substance.
It is usually called freezing, but can also be called solidification. It occurs when the temperature goes below the freezing temperature of a substance and that substance solidifies, or becomes hard.
When the piston goes up the heat temperature decreases while when the piston is down the heat temperature is increases.
Kinetic energy of a substance is the energy of motion of its particles. Temperature is a measure of this quality. When you increase the kinetic energy of a substance, you increase the motion and collisions between its particles, and its temperature goes up.
Solidification is the process of freezing of the substance from liquid form into the solid form as the heat goes out of the substance ie as the temperature decreases.
Melting point. Common sense goes a long way in science.
The substance will be compressed (increase in density) and if the compression is adiabatic, the temperature will go up since there is work being done on the system.
A physical change is one in which the shape, size, appearance or state, of a substance may alter, but its chemical composition remains same.
"Melting" and "freezing" are transition actions, going from solid-to-liquid form and liquid-to-solid form respectively. The point is the same transition temperature of that particular substance. The same goes for the transition temperature of the "boiling point" and "condensation point" of a substance.
The angle of insolation into a surface is largest when the surface directly faces the Sun. That coincides with the temperature rising. So the angle of insolation goes up as the temperature goes up.
That's the heat of fusion.
As temperature goes up, the volume goes down