What happens to coffee as the heat enery escapes from a polystyrene cup

It get cooler, of course.

The coffee cools off?

When heat energy escapes from a polystyrene cup, the coffee inside undergoes a series of changes. Heat transfer occurs in three ways: conduction, convection, and radiation.

Conduction is the process of heat transfer through direct contact between objects. In the case of a polystyrene cup, the heat energy from the coffee gradually conducts through the walls of the cup to the surrounding environment. Polystyrene is a poor conductor of heat, so it helps to retain the temperature of the coffee for a longer time compared to other materials.

Convection is the process of heat transfer through the movement of a fluid, such as air or water. As the coffee loses heat, the surrounding air near the surface of the cup gets warmer. This warm air expands, becomes less dense, and rises, creating a convection current. This movement allows fresh cooler air to come in contact with the surface of the coffee, causing further heat loss.

Radiation is the transfer of heat energy through electromagnetic waves. All objects emit and absorb radiation. As the coffee cools down, it emits thermal radiation in the form of infrared waves. However, in a polystyrene cup, the walls reflect a significant amount of this radiant heat back into the coffee, reducing the rate of heat loss through radiation.

As the heat energy escapes from the polystyrene cup, the temperature of the coffee gradually decreases. The rate of cooling depends on factors such as the initial temperature of the coffee, the temperature of the surrounding environment, the thickness of the cup, and the efficiency of the cup in insulating heat.

To observe the changes in the coffee, you can measure its temperature using a thermometer at regular intervals of time. By recording these measurements and plotting them on a graph, you can visually see how the temperature decreases over time. This process is known as temperature decay or cooling curve analysis.