The energy required for a particular change in state is given by the specific latent heat. Specific latent heat is the amount of energy required to change the state of 1 ... of ice into 1 kg of water at its melting point of 0°C. The same amount of energy ... stored or released as the temperature of a system changes can be calculated.
Gravity only becomes noticeable when there is a really massive object like a moon, planet or star. We are pulled down towards the ground because of gravity. The gravitational force pulls in the direction towards the centre of any object.
