During a phase change what happens to the temperature?

During a phase change the substance or objects temperature increases or decreases depending on which way they go, Solid to liquid to gas needs added heat which makes it an endothermic reaction. Gas to liquid to solid loses heat energy to slow down its particles this is an exothermic reaction.

The temperature either rises or falls during a state change. 
Ex. 
Melting from ice to water~ the temperature is rising.

OR

Ex. 
From a gas to a liquid~ the temperature is falling.

Kinetic energy = 1/2mv^2. since the mass is constant we can form a ratio of it's kinetic energy at 60 divided by that at 30 to see ke(60)/ke(30) = +(60^2)/30^2). this may be said to 300% increase.