Question

What is the cause of thermal motion in particles of matter? State what happens to the motion of the particles when:
Heat is taken away from the body
Heat is supplied to the body

Answer 1

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