EXPANSION & CONTRACTION
Expansion:
• The process in which the volume of a substance increases with the increase in temperature is termed as expansion.
Figure 6- Electric cables expand in summer season
• Matter increases in volume when there is an increase in temperature.
• The volume increases the most in case of gases.
• When something expands; it takes up more space.
Figure 8- Hot air balloon
• Hot air balloon flies in the air because of the hot air present inside it. Due to this hot air, balloon expands.
Exception:
Water expands when cooled or frozen and contracts when warmed or heated.
Contraction:
• The process in which the volume of the substance decreases with the decrease in temperature is termed as contraction.
Figure 9- Electric cables contract in winter season
• When something contracts; it shrinks.
Figure 10- Hot air balloon
• Hot air balloon deflates (shrinks) because of the cold air in the atmosphere. Due to this cold air, balloon contracts.