REVOLUTION AROUND THE SUN

The Earth revolves around the sun. One revolution takes 365 ¼ days (one

year) to be completed. The path the Earth travels is called an

orbit.

At each position in the orbit people in different parts of the world experience different seasons.

In the Southern hemisphere, midsummer’s day falls on 21 December called the summer solstice.

During the summer solstice we have long days and short nights and receive the most insolation. We have the longest day and the shortest night.

Between December and march we move from summer to autumn and days become shorter.

SH Mid-autumn day falls on 21 March –called autumn equinox and the days and nights are at equal lengths.

Between March and June we move from autumn to winter - days become more shorter -less insolation.

SH Mid-winter day fall on 21 June, this is called winter solstice. We then have the longest night and the shortest day.

Lastly, between June and September we move from winter to spring.

SH Mid-spring day falls on 23rd September called-the spring equinox and the day and night are of equal length.

ACTIVITY

(Using image on next slide)1. Which season is the southern hemisphere

experiencing?2. How does the diagram show this?3. Which part of the Earth’s surface has 24 hours

of daylight? 4. Which date in the year does this diagram

represent?5. Name the two factors that cause the Earth to

have seasons.