Question

When an object is heated, the molecules that make up the object :

• A. begin to move faster
• B. lose energy
• C. become heavier
• D. become lighter

Answer 1

The correct option is A begin to move faster

When heat is added to a substance, the molecules and atoms vibrate faster. As atoms vibrate faster, the space between atoms increases. The motion and spacing of the particles determines the state of matter of the substance. The end result of increased molecular motion is that the object expands and takes up more space.

Mass of the object remains the same, however solids, liquids and gases all expand when heat is added.