Page 230 - Primary Five Science
P. 230
Expansion in gases
Expansion is fastest in gases.
The water heats the bottle and the air inside the bottle ex-
pands causing the balloon to expand.
Application of expansion and contraction in daily life
Expansion Gaps in Concrete Roads
In hot summer, the concrete used to build roads expands. If no
space is provided for its expansion, the road surface cracks. To
avoid such damage, small gaps are left after every few meters
in the Constitution of concrete roads of footpaths.
Railway lines
Two sections of a railway track are not welded together. In-
stead they are laid with gaps between them. This allows ex-
pansion and contraction of rails during hot and cold days.
