Definition
The temperature at which a solid substance changes into a liquid. For a pure substance at a given pressure, the melting point is a fixed, repeatable temperature.
Plain English
The temperature at which something solid turns into a liquid.
Context Anchor
Seen in weather, icing, and aircraft maintenance discussions involving ice, metals, plastics, solder, or other materials.
Derivation
From the Old English meltan, meaning to dissolve or become liquid. The melting point is simply the point on the temperature scale where that change happens.
Why Pilots Care
Aircraft parts and engine materials are selected so their melting points exceed operating temperatures to preserve strength and prevent failure.
Grounding Statement
Ice has a familiar melting point: when it reaches about 32°F or 0°C, it can begin changing from solid ice into liquid water.
Intuition Check
Melting point does not mean the substance instantly becomes fully liquid all at once. It means the temperature where the change from solid to liquid begins and can continue as heat is added.
Example Sentence 1
Aluminum has a much lower melting point than steel, which is why aluminum aircraft structures must be kept away from intense heat sources.
Example Sentence 2
During preflight, the mechanic confirmed the melting point of the solder used on electrical connections remained well above any expected heat exposure.