Which term describes the capacity of a material to expand when heated?

Which term describes the capacity of a material to expand when heated?

• A. Grain lines
• B. Thermal expansion
• C. Habit
• D. Twinned crystal

Answer: (B)

Thermal expansion describes the capacity of a material to expand when heated. As temperature rises, atoms vibrate more and occupy more space on average, causing the material to lengthen or increase in volume. The amount it expands is quantified by the coefficient of thermal expansion, which varies among materials. The other terms describe different concepts: grain lines are boundaries between crystalline grains formed in metals, habit refers to the typical crystal shape of a mineral, and a twinned crystal is a crystal that has a symmetrical intergrowth with a twin domain. None of these capture how size changes with temperature.

Thermal expansion describes the capacity of a material to expand when heated. As temperature rises, atoms vibrate more and occupy more space on average, causing the material to lengthen or increase in volume. The amount it expands is quantified by the coefficient of thermal expansion, which varies among materials.

The other terms describe different concepts: grain lines are boundaries between crystalline grains formed in metals, habit refers to the typical crystal shape of a mineral, and a twinned crystal is a crystal that has a symmetrical intergrowth with a twin domain. None of these capture how size changes with temperature.