Theory question 203
Latitude, Longitude and Time(a) (i) With the aid of a diagram, identify the main lines of latitude. (ii) Calculate the distance between Addis Ababa in Ethiopia (latitude 10°N) and Maseru in Lesotho (latitude 30°S). (b) (i) Define revolution of the earth. (ii) Describe how revolution of the earth affects the length of day and night in the Northern Hemisphere.
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(a)(i) Diagram of a globe showing the Equator (0°), Tropic of Cancer (23½°N), Tropic of Capricorn (23½°S), Arctic Circle (66½°N), Antarctic Circle (66½°S), North and South Poles (90°).
(ii) Places are on opposite sides of the Equator, so add: 10° + 30° = 40°; 1° of latitude ≈ 111 km (69 miles), so 40 × 111 = about 4,440 km.
(b)(i) Revolution is the movement of the earth round the sun in its orbit, taking 365¼ days (one year).
(ii) Because the axis is tilted 23½° and keeps the same direction, the overhead sun moves between the tropics; about 21 June (summer solstice) the Northern Hemisphere leans towards the sun: days longer than nights, 24 hours of daylight north of the Arctic Circle; about 22 December (winter solstice) it leans away: nights longer, 24 hours of darkness north of the Arctic Circle; at the equinoxes (21 March, 23 September) the sun is overhead at the Equator and day equals night everywhere; the length of day changes more the further north a place is.
Add the latitudes when places are in different hemispheres.