What causes global convection currents to form

uneven heating of Earth's surface

Explanation:

The motion of air between equator and poles is known as global winds. The equatorial region gets more direct sun heat than poles. This causes air above equator to heat and rise. The cold air above poles which is denser rushes towards the equator. These convection currents on small scale cause local winds and large scale causes global winds.

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .

an energy transformation flow diagram is shown

where is it ?