Theory question 202
The Earth and Solar System(a) Distinguish between rotation and revolution of the earth
(b) Highlight any two effects of either rotation or revolution of the earth
(c) With the aid of a suitable diagram describe an eclipse of the sun
Show the model answer
(a) Rotation: the earth spinning on its axis from west to east once in 24 hours (a day). Revolution: the earth moving round the sun in its orbit once in 365¼ days (a year)
(b) Rotation: day and night; deflection of winds and ocean currents (Coriolis force); time difference between longitudes; daily tides/sunrise-sunset. (Revolution: seasons; varying length of day and night; changing altitude of the midday sun)
(c) Diagram: sun – moon – earth in a straight line; the moon blocks the sun's rays; umbra (total eclipse) and penumbra (partial eclipse) on the earth; occurs at new moon, lasts only a few minutes
In a solar eclipse the moon is between the sun and the earth.