internal energy

• hot air always rises
• evaporation increases when more movement of air across the liquid's surface is created
• particles which have a higher kinetic energy are more energetic and 'break free' from the water becoming a gas. when the evaporation occurs, it causes cooling down in the liquid that has been left behind
• increasing the movement of air across liquid affects the rate of evaporation (increases). for example, wet clothes dry faster in a breeze
• boiling only takes place at a particular temperature because the particles are vibrating at a particular speed. this is called the boiling point and it occurs throughout the liquid
• evaporation takes place from the SURFACE of the liquid at all temperatures
• evaporation is when a liquid changes to a gas
• potential energy is due to the POSITION of the particles in the object, not the amount of matter in the object
• kinetic energy is due to the MOVEMENT of particles
• internal energy is the sum of the kinetic and potential energies of the particles in a system
• internal energy is stored by the particles (atoms and molecules) of a substance
• when an object is heated it expands because its atoms gain kinetic energy and move further apart.
• the temperature of a body depends on how much internal energy it has per unit mass