Question 5
- With the aid of suitable diagrams, describe the following proofs supporting the spherical shape of the earth:
- circumnavigation;
- Bedford Level experiment;
- Ship visibility.
- Highlight three differences between equinoxes and solstices.
Observation
This was a popular question among the candidates. Quite a good proportion of the candidates who answered the question were able to show the proofs of earth’s spherical nature by backing up their explanations with good diagrams. However, the (b) component of the question which centred on the differences between equinoxes and solstices was not properly answered by most of the candidates. The differences between equinoxes and solstices are:
- equinox could be spring or autumnal while solstice could be summer or winter
- equinox means equal lengths of day and night while solstice mean unequal length of day and night
- equinoxes occur on March 21st and September 23rd while solstices occur on June 21st and December 22nd
- during equinoxes the duration of day and night is constantly 12 hours, while during solstices places north of the Antarctic Circle or south of the Antarctic Circle have 24 hours day light or 24 hours darkness respectively.
- at equinoxes, the days and nights are equal whereas in solstices days are longer in summer and shorter in winter.
- at equinox, the sun is vertically overhead at the Equator while during solstices the sun is vertically overhead at either the Tropics of Cancer or Capricorn