EXPANSION & CONTRACTION
• 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.
Water expands when cooled or frozen and contracts when warmed or heated.
• 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.