When someone touches a cold surface the perception of cold is the sensation of heat flowing from the body to the cold object. Temperature is a measure of the average molecular kinetic energy of a body. Temperature is a local property and doesn t depend on the size of the body. Heat is the flow of energy from one body to another whereas internal energy is the energy contained within a particular body. The relative temperature of two bodies in contact determines the direction of heat flow.
Heat flows from hot to cold.
A substance that heats up quickly has a low heat capacity. The temperature of land masses surrounded by large bodies of water remains relatively constant because the temperature of the surrounding water is relatively constant. This is due to water s relatively high specific heat. If the glass is thick there will be a significant mismatch of temperatures between the outside and inside of the glass. This will cause the inside to expand considerably more than the outside and lead to the glass cracking.