What happens to the heat of a cup of tea when left on the table?
When an object is hotter than its surroundings, then a process called heat transfer happens. This is when heat (or thermal energy) flows from the hotter object to the cooler one, for example a cup of tea cooling down on a table. Some of the heat will be lost to the table through conduction (through direct contact with eachother), while some will be lost through convection (in the steam rising up from the cup). The rest of the heat will be lost through radiation (heat transfer through empty space), or the sides of the cup being in contact with the cooler air. Heat transfer will only happen when there is a difference in temperature. When the two objects are at the same temperature (for example the cup and the table, or the cup and the air), the transfer stops and is said to be in equilibrium (meaning in the same state). This is why a hot object in room temperature can’t cool down further than the temperature of the room.
