Question

When you put an ice cube in a glass of warm tea, which of the following happens?

(a) Cold flows from the ice cube into the tea.

(b) Cold flows from the ice cube into the tea and heat flows from the tea into the ice cube.

(c) Heat flows from the tea into the ice cube.

(d) Neither heat nor cold flows. Only temperature flows between the ice and the tea.

Short answer

(c) Heat flows from the tea into the ice cube.

Step-by-step solution

Understanding the heat transfer between two bodies

The heat transfer takes place from the hotter body to the colder body. Due to the transfer of heat, the body changes its phase. By the same effect, the temperature of the body will vary accordingly.

Explanation for the transfer of heat when the person puts an ice cube into a warm tea

The ice cube is placed in the glass of warm tea. The molecules of the tea move quickly, and the warm molecules have high kinetic energy. In contrast, the molecules of ice have low kinetic energy.

The collision of molecules takes place between the ice molecules and the tea molecules. Due to the high kinetic energy of the tea molecules, a transfer of heat energy takes place from the warmer tea to the ice cube.

Due to the transfer of heat, ice melting occurs, and the tea starts cooling while heating the ice cube. The temperature of the ice cube starts increasing, and the temperature of the tea decreases accordingly.

Thus, heat flows from the tea into the ice cube.