Question

Which image shows effect of thermal expansion?

Answer 1

The tendency of matter to change its shape, area, volume, and density with a change in temperature is called Thermal Expansion. When most substances are heated, their molecules begin to vibrate and move creating more distance between themselves.[2]
With increase in energy the particles start moving faster and the inter-molecular forces between them weakens. Thermal expansion is expressed as the relative or fractional change in length or volume per unit change in temperature.[2]