To understand how the seasons are made you must first have clearly in mind the positions of the tilted Earth in different parts of its orbit round the Sun. The things needed for this experiment are a nice round apple, a candle, a piece of string, a safety-pin and a knitting needle.
Fig. 78.—Circle Around Candle Marked with Seasons.
Place the candle in the center of a table and call it the Sun; draw a circle a foot in diameter on the table top and around the candle with a bit of chalk. Mark one side September 22; at the next quarter of the circle mark December 21; directly opposite the September mark chalk in March 21, and finally between March and September mark June 21, all of which is shown in [Fig. 78].
Push the knitting needle through the center of the apple, call the apple the Earth and call one end of the knitting needle the north pole and the other end the south pole. Fasten the safety-pin through the skin of the apple and tie the string to the pin so that when the string is tied to a tack in the ceiling or some one is holding it directly over the candle the knitting needle of the apple will be tilted to the perpendicular, as shown in [Fig. 79].
Fig. 79.—Apple to Represent Earth
Suspended in Air.
Fig. 80.—Position of the Earth
and Sun in Autumn.
