Unit 1: The Earth in the Universe                                            1   2   3   4

3.2. The seasons

The seasons are due to the different amount of solar radiation that reaches the Earth's surface. This energy changes throughout the year due to the revolution of the Earth around the Sun and the fact that its rotational axis is tilted.

The seasons are divided according to the length of the day and their beginning and end are marked by particular days:

- Equinoxes are the two days of the year when day and night

   last the same time (12 hours).

- Solstices are the two days of the year when there is more difference

   between the duration of day and night.

The Earth is furthest from the Sun (aphelion) during summer in Northern hemisphere. However, it is hotter because there are more hours of sunlight per day and the Sun's rays strike the Earth's surface at a more direct angle providing more heat.

The inverse situation takes place in the Southern hemisphere where it is winter.

3.5. Change the following sentences to make them true:

       a. During the spring equinox, the Sun illuminates the northern hemisphere

           more than the southern hemisphere.

       b. During the autumn equinox, days are long and nights are short

     in the northern hemisphere.

       c. Summer solstice is on 22^nd September.

       d. Winter solstice is when day and night have the same length.

3.6. Listen and relate each definition with the following terms: