Which scenario correctly illustrates Charles Law?

The scenario that illustrates Charles's Law is when a balloon expands as it is heated. Charles's Law states that the volume of a gas is directly proportional to its temperature (in Kelvin) when the pressure is held constant.

When the temperature of the gas inside the balloon increases due to heating, the kinetic energy of the gas molecules increases as well. This increased kinetic energy makes the molecules move more vigorously and push against the walls of the balloon, resulting in an increase in volume. Therefore, as the temperature goes up, the volume of the gas inside the balloon expands, perfectly demonstrating Charles's Law.

The other options do not depict the relationship described by Charles's Law. The contraction of a metal piece in cold temperatures relates to thermal contraction rather than gas behavior. A gas remaining constant in a sealed container does not illustrate a change in volume with temperature, and the melting of an ice cube is a phase change involving solids and liquids, which is unrelated to gas laws.