CBSE Class 9 Answered

Temperature is directly proportional to the average kinetic energy. So if temperature is increased,the average kinetic energy of the molecules will also increase.

Ex:
In an ice cube(solid), the molecules are packed.If you increase the temperature the average kinetic energy of the molecules will begin to increase and move out of place. When this happens the ice starts to melt. As temp continues to increase the molecules will have gained enough kinetic energy to escape the liquid into water vapor(gas).