An important example of convection
currents that can be interpreted in this manner is the creation
of breezes over land masses next to large bodies of water.
Thus, during the day the air above the water will be cooler
than that over the land.
This creates a low pressure
area over the land, relative to the high pressure area over
the water, and subsequently one finds breezes blowing
from the water to the land.
On the other hand, during the
night water cools off more slowly than the land, and the
air above the water is slightly warmer than over the land.
This creates a low pressure area over the water relative
to the high pressure area over the land, and breezes will
blow from the land to the water. Places near the sea have
pleasant and moderate climates because of the occurrence
of land breezes and sea breezes.
Land breeze: the cold
air blowing from the land towards the sea during night is
called land breeze. Land being a good absorber is also a
good radiator . Thus during the night , the land loses more
heat by radiation. The specific heat capacity of land being
lower than that of water, its temperatures in the early
hours of the morning are lower than that of the sea. The
air above the sea being warmer , expands, rises up and convection
currents of cold air flow from the land towards the sea,
forming land breezes.
Sea breezes:during day time , land becomes more heated
than the sea . In the evening , air above the land, being
more heated, expands, rises up and the colder air from above
the sea surface blows towards the land to take its place.
This sets up he convection currents which forms the sea
This would explain why:
- The freezing unit is fitted to the top of the refrigerator
- It is fallacious to install air conditioners near the
- Ventilators in the room are provided near the ceiling
- Factories are fitted with chimneys
More of this in the animation