Heat Transfer: แบบฝึกหัด

Four rods of the same size but made of different materials are placed into a beaker of hot water. If a small piece of wax is placed on the top end of each rod, which rod will most likely cause the wax to melt first?

When two objects with different temperatures are placed in contact, heat naturally flows between them. In which direction does this heat transfer occur?

Explain why air conditioners are usually installed high up on the wall near the ceiling rather than near the floor, in terms of heat transfer and air movement.

A metal spoon and a wooden spoon of the same size and at room temperature (\(24^\circ\text{C}\)) are placed on a table. When a person touches both spoons with their bare hands, explain why the metal spoon feels significantly colder than the wooden spoon, even though they are at the exact same temperature.

A student places an ice cube on a kitchen countertop at room temperature (\(25^{\circ}\text{C}\)).

(a) In which direction does heat flow between the ice cube and the surrounding air?

(b) What physical state change occurs to the ice cube as it absorbs heat?

(c) Identify whether this change of state is a reversible or irreversible change.

A student conducts an experiment to test how heat travels through different materials. Three rods of the same length and thickness, made of copper, glass, and wood, are placed in a beaker of boiling water at \( 100^{\circ}C \). A small piece of wax is placed on the top end of each rod.

(a) On which rod will the wax melt first? Explain your answer based on the property of the material. (2 points)

(b) What is the name of this method of heat transfer through solids? (1 point)

(c) Based on this experiment, why are the handles of cooking pots usually made of plastic or wood? (1 point)