The axis of the earth is an imaginary line that runs through the center of the earth. This axis is slightly titled. The earth this is slightly titled. The two points on the surface of the earth where the axis seems to center are called the poles: North Pole and South Pole.
The equator is another imaginary line around the earth, exactly halfway between the poles. It divides the earth into two equal halves, the Northern hemisphere and Southern hemisphere. We know that the spinning of the earth, called rotation, causes day and night. The movement of the earth around the sun, that is its revolution, causes seasons.
Seasons of earth
As the earth orbits around the sun, the longer days of summer change into the shorter days of winter. This means that the length and temperature of the days change. This is why when the North Pole is way from the sun, the South Pole is towards it. Northern Hemisphere is away from the sun when the southern Hemisphere is towards it. So the season in the Northern Hemisphere can always never be the same as the season in the Southern Hemisphere.
What happens when the earth goes around the sun?
A) When the North Pole is towards the sun it is summer in the Northern Hemisphere. The sun seems to be hotter because its ray falls directly on earth. At the North Pole there is sunlight throughout the day and during night. During this time the South Pole is turned away from the sun. So the sun rays do not reach the South Pole and there is no light at all. It is winter in the southern Hemisphere.
B) When the North Pole is turned away from the sun, it is winter in the northern Hemisphere. The days are shorter and the sun seems low in the sky. The North Pole is in darkness, now it is summer in the southern Hemisphere.
The distance of the South Pole and North Pole from the sun would be the same. There would be no changes of seasons. So the two factors which cause seasons are
1) The titled axis of the earth
2) The revolution of the earth