What is the temperature at which a substance changes from a solid to a liquid?

2 Answers

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beateach | Elementary School Teacher | (Level 1) Educator

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The precise temperature at which a substance changes from a solid to a liquid is called its melting point. The temperature to reach the melting point varies for different types of solids. Different conditions such as changes in pressure can affect the melting point. The melting point of a substance is achieved when the molecules in the solid substance are heated until they have enough movement in them to change into the liquid state.

An experiment that is often used to show the change of state that occurs when ice, a solid, is heated until it reaches its melting point and changes to its liquid form, water. The melting point of the ice is just above one degree Celsius, thirty-two degrees Fahrenheit, when in normal pressure conditions.

When pressure is lower, solids usually reach their melting temperature more quickly.

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gsenviro | College Teacher | (Level 1) Educator Emeritus

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The temperature at which a substance changes from a solid state to a liquid state is called the melting point. It is the opposite of the freezing point, the temperature at which liquid turns to solid. The melting point of ice (solid form of water) to liquid water is 0 degrees Celsius. Melting point is a function of pressure and hence pressure is reported along with the melting point of a substance. The 0 degree Celcius melting point of ice is observed at a pressure of about 1 atmosphere. 

The melting point of a substance can be used to measure its purity. An element has a well-defined melting point,whereas a mixture will have a different melting point (and generally, it would be lower than that of the pure element).