What determines whether a material melts or burns when heated?

Melting is a change of state. Burning is a chemical reaction (usually with oxygen in the air). What determines whether something melts or burns is whether, as that object heats, it reacts quickly and exothermically with oxygen in the air. As you add thermal energy to a material the individual atom's also gain energy.

Explanation:

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i don't see a text, but i am gonna assume this *orbit* the curved path, usually elliptical, described by a planet, satellite, spaceship, etc., around a celestial body, as the sun.