Question

Where has the thermal energy in the polystyrene cup when it has cooled down to room temperature?

(Talk about how it decreases as the particles collide less frequently, and then thermal equilibrium is reached with room temperature)

Answer 1

When a polystyrene cup cools down to room temperature, it means that the thermal energy in the cup has been transferred to its surroundings until thermal equilibrium is reached. Thermal energy transfer can occur through conduction, convection, and radiation. Conduction involves molecules transferring kinetic energy to one another through collisions. In this case, the thermal energy from the cup is transferred to the air molecules around it through collisions until both the cup and its surroundings reach the same temperature.

Step-by-step explanation:

Thermal energy refers to the energy contained within a system that is responsible for its temperature. Heat is the flow of thermal energy. When two objects or systems are at different temperatures, heat will flow from the hotter object to the cooler one until both objects reach the same temperature. This state is called thermal equilibrium.

There are three ways that heat can be transferred: conduction, convection, and radiation. Conduction is the transfer of heat through direct contact between particles of a substance without moving the particles to a new location. This happens when molecules collide with each other and transfer their kinetic energy. For example, when you touch a hot pan on the stove, heat is transferred from the pan to your hand through conduction.

Convection occurs when hot air rises, allowing cooler air to come in and be heated. This creates a cycle where hot air rises and cool air sinks, creating a current that transfers heat. For example, when you boil water on the stove, the heat from the stove heats the water at the bottom of the pot. This hot water rises to the top and cooler water sinks to the bottom to be heated, creating a convection current that transfers heat throughout the pot.

Radiation is the transfer of heat through electromagnetic waves. This can happen even in a vacuum where there are no particles to transfer heat through conduction or convection. For example, when you stand in front of a fire, you can feel the heat even though you are not touching it. This is because heat is being transferred to you through radiation.

In the case of a polystyrene cup cooling down to room temperature, heat is transferred from the cup to its surroundings through conduction until thermal equilibrium is reached and both the cup and its surroundings are at the same temperature.

Answer 2

The thermal energy in a polystyrene cup, or any object for that matter, is stored in the kinetic energy of its particles. When a hot object, such as a cup of hot liquid, is left to cool down to room temperature, the thermal energy stored in the cup decreases as the particles collide less frequently.

As the cup and its contents cool, the particles within the cup begin to lose kinetic energy as they collide with each other and with the surrounding environment. As the particles lose energy, they move more slowly, which in turn decreases the amount of thermal energy stored in the cup.

Eventually, the cup and its contents reach a state of thermal equilibrium with the surrounding environment, meaning that they have reached the same temperature as their surroundings. At this point, the thermal energy stored in the cup has been completely transferred to the environment, and the cup is said to be at room temperature.

Overall, the decrease in thermal energy in a polystyrene cup when it cools down to room temperature is a result of the transfer of kinetic energy from the particles within the cup to the particles in the surrounding environment, through collisions and other forms of energy transfer.

Have a Great Day!

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