The change from liquid to solid, or the reverse of melting, is called A Condensation B. freezing C. boiling D. sublimation
The correct answer and explanation is:
Correct Answer: B. Freezing
Freezing is the process in which a liquid turns into a solid. This change in state occurs when the temperature of the liquid drops to or below its freezing point. During freezing, the particles in the liquid lose energy and move more slowly. As they slow down, they become more organized and lock into fixed positions to form a solid.
This process is the reverse of melting. While melting involves adding heat to change a solid into a liquid, freezing involves removing heat to change a liquid into a solid. For example, water freezes at 0°C. When water reaches this temperature, its molecules arrange themselves into a crystalline structure that forms ice. This transformation is a physical change because the substance itself—H₂O—remains the same; only its state changes.
Freezing is an important concept in many areas of science and daily life. In biology, freezing helps preserve cells and tissues. In the food industry, it is used to preserve food and extend its shelf life. In weather systems, freezing temperatures result in frost, ice, and snow, which can impact transportation, agriculture, and ecosystems.
It is important not to confuse freezing with condensation, boiling, or sublimation. Condensation is the change from gas to liquid, boiling is the change from liquid to gas, and sublimation is the direct change from solid to gas without passing through the liquid phase. Each of these processes involves changes in energy and particle movement, but freezing specifically refers to the formation of a solid from a liquid.
In summary, freezing is the phase transition from liquid to solid. It involves the loss of thermal energy and a decrease in the movement of particles, causing them to form a structured, solid state.