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melting

Primary Information
Secondary Information

Definition

Melting is the process of a solid changing to a liquid. This happens when the molecules in the solid gain enough energy to overcome the forces of attraction between them. The melting point of a substance is the temperature at which it melts.

The melting point of a substance depends on the strength of the forces of attraction between its molecules. Substances with strong forces of attraction, such as metals, have high melting points. Substances with weak forces of attraction, such as ice, have low melting points.

The melting point of a substance can also be affected by pressure. When pressure is applied to a solid, the molecules are forced closer together, which increases the forces of attraction between them. This can raise the melting point of the substance.

Melting is a reversible process. When a liquid is cooled, the molecules lose energy and eventually slow down enough to form a solid again. This process is called freezing.

How can the word be used?

The snow is melting.

melting

Different forms of the word

Noun:

  • The process of changing from a solid to a liquid.

Adjective:

  • Relating to or caused by melting.

Verb:

  • To change from a solid to a liquid.

Etymology

The word "melting" comes from the Old English word "meltan", which means "to dissolve".

The word "melting" was first used in English in the 13th century. It was originally used to describe the process of ice melting, but it soon came to be used in a more general sense to describe the process of any solid changing to a liquid.

Question

What does melting mean?

AQA Science Exam Question and Answer

Question:

Explain the concept of melting in the context of changes of state for substances. Provide examples of substances that undergo melting and discuss the process and energy changes involved.

Answer:

Melting is a phase transition that occurs when a substance changes from a solid state to a liquid state due to an increase in temperature. During melting, the kinetic energy of the particles within the substance increases, causing them to overcome the attractive forces that hold them in a fixed lattice structure.

For example, consider ice (solid water). As heat is added to ice, its temperature rises. At the melting point, which is 0 degrees Celsius for ice, the particles have gained enough energy to break free from their rigid arrangement, and the substance transitions into liquid water.

During melting, the energy supplied is used to weaken or break the intermolecular forces between particles, rather than increasing their kinetic energy further. This energy is known as the heat of fusion. The heat of fusion is the energy required to change a unit mass of a substance from solid to liquid at its melting point.

The reverse process, freezing, occurs when a liquid loses energy and transitions to a solid. Melting and freezing occur at the same temperature for a given substance, reflecting the equilibrium between solid and liquid phases.

Understanding melting and changes of state is vital in various fields, from cooking and materials science to climate science. It underlines the dynamic nature of matter and energy and provides insights into how substances transform as they gain or lose thermal energy.