Ch 14Solar Radiation, Heat Balance and Temperature — Class 11 Geography, concept-first.

We live at the bottom of a huge pile of air. You rarely notice it, but it is always there — you feel it only when it moves. That moving air is what we call wind.

The earth’s surface receives most of its energy in short wavelengths. This incoming solar radiation is called insolation.

The amount and intensity of insolation reaching the Earth’s surface are not constant. They change through the day, across a season, and from one year to the next.

The atmosphere does not block sunlight; it lets most of it through. But the light that reaches the ground has already been changed — absorbed in part, scattered in part — by the air it travelled throu…

The amount of solar energy that actually reaches the ground is not spread evenly across the planet. It changes with latitude, with the seasons, and even with whether you are standing on land or at sea…

The atmosphere is not heated directly by the Sun. Instead, the Sun's energy first warms the Earth's surface, and the Earth then passes that heat upward to the air.

The earth’s surface receives solar energy in short-wave form, but once heated, it does not keep that energy to itself.

The Earth as a whole neither gains nor loses heat over time — it maintains a stable temperature. This balance is possible only because the heat the planet receives as insolation is exactly equal to th…

The Earth does not receive the same amount of solar energy everywhere. Because the planet is a sphere, the tropics get far more incoming radiation than the poles.

Heat and temperature are often used interchangeably, but they are not the same thing. Heat is the energy created by the molecular movement of the particles that make up a substance.

The temperature of air at any place is not a matter of chance. It is controlled by a small set of physical factors, and the most important of them are the latitude of the place, its altitude, and its…

The way heat is spread across the Earth’s surface is not uniform — it changes with latitude, season, and the nature of the underlying surface.

Normally, temperature decreases as elevation increases. That steady drop is the normal lapse rate. But sometimes the situation flips: temperature increases with height instead of decreasing.