Seasons - Causes and Effects on our Weather
Seasons are a very important element in our lives. They have an influence on what we wear, what we eat and what we do in our free time. They also affect the mood we are in.
In ancient civilizations people observed that the sun was at different places during different times of the year. But they didn’t understand how this led to the changes in seasons.
Towards the end of the Middle Ages the astronomer Nicolai Copernicus changed our view of the solar system. He said that the sun, not the Earth, was at its centre and all objects moved around it. Today we know that the Earth moves in an elliptical path around the sun. The Earth spins around its axis and is tilted towards or away from the sun. This means that the northern and southern parts of the Earth get different amounts of sunlight throughout the year. The sun gives us heat too and temperatures change, depending on how steep the sun’s rays come in.
The seasons start with solstices and equinoxes. Solstices occur every year in June and December. They mark the beginning of summer and winter. The Earth is tilted farthest towards or away from the sun. The equinoxes occur in March and September. On March 20 th or 21 st the sun seems to be right above the equator and moving towards the north. At the end of September the sun passes the equator on its way to the south. Day and night have the same length almost all over the planet. The exact day and time of a season’s beginning always changes a bit.
The Earth and its path around the sun
The change of seasons also has an effect on our weather. In June, the northern hemisphere is tilted towards the sun. The sun’s rays are more direct, and they do not have to travel so far to reach the surface. More radiation reaches the Earth. The days are longer and more light gets to the surface .There it is changed to heat. At the same time the southern hemisphere is tilted away from the sun. Rays have to travel longer to get to the surface and there are fewer hours of daylight.
Although June and December mark the official beginning of summer and winter, these months are not always the hottest and coldest of the year. Temperatures also depend on the heat that is absorbed and reflected by land and the oceans. In most cases the hottest months in the northern hemisphere are July and August and coldest times of the year occur in January and February.
- affect = change
- amount = how much of something
- ancient = old
- astronomer = a person who studies the sun, stars and the planets
- effect = change, result
- hemisphere = half of the earth
- influence = power to change something
- length = how long something is
- mark = are
- mood = how we feel
- path = track, route
- radiation = here: heat or light
- ray = a line of light that comes form the sun
- solar system = the sun and the planets
- spin = revolve, go around
- steep = not flat
- surface = the top layer of land or water
- tilt = to move so that one side is higher than the other