The paper "Causes of Seasons" is an outstanding example of an assignment on environmental studies. It is a well-known fact that the earth follows an elliptical around the sun which is completed in 3651/4 days. But contrary to popular belief the distance of the earth from the sun has no bearing on the changing of the seasons. For example, the earth is nearest to the sun on 3rd January (perihelion) and farthest from the sun on 4th July (aphelion). Thus if distance were a factor in deciding seasons then summer should be January, and winter in July when the earth is farthest from the sun.
Changes in the earth’ s temperature occur due to the angle at which sunlight enters the earth’ s atmosphere. In winter the sun rays reach the earth at a lower angle covering more distance. They lose some of the heat during traveling and are cooler. These rays are also spread over a greater area of the earth’ s surface for a shorter duration so that the covered area becomes less warm and cold conditions prevail. In summer the sun rays reach the earth from a higher angle and travel a shorter distance in the atmosphere.
These rays reach the earth faster and are consequently hotter. Additionally, the higher angle of entry leads to a concentration of the rays on a smaller area which leads to a greater warming of the earth’ s surface and summer prevails. Thus the phenomena of changing seasons are in fact due to the angle at which the earth lies in relation to the sun during its orbit. For example on 21st December the earth is positioned so that the northern hemisphere is tilted away from the suns rays and they enter the atmosphere at a greater angle covering a longer distance so it is winter; but the southern hemisphere is tilted towards the sun and the suns rays travel through the atmosphere faster and at a lesser angle so it is summer.
On 21st June the cycle is reversed and summer replaces winter and vice- versa.