SCHOOL COURSES. 39 



3. Germination of Beaus, Cress, Wheat, etc.* 



4. Examination of Pupae ; drawing and colouring. 



5. Physical study : Cause of the Seasons. 



After the pupils have realised the close dependence of 

 life upon the seasons, a study as to their immediate 

 cause is appropriate. The following should be made 

 clear : 



The sun is the source of heat upon the earth. 



Owing to the inclination of the axis of rotation of the 

 earth the distribution of solar heat upon the earth 

 varies at different times, thus producing the seasons. 



Exactly how this is brought about should be demon- 

 strated upon the school globe ; observations should 

 be made on the sun's altitude now and at each 

 season. Show the effect of obliquity on the sun's 

 rays, e.g. when this is great the heat is spread over 

 a larger area, a greater depth of atmosphere has 

 to be traversed, and thus more heat is absorbed 

 (see Eig. 2). A comparison of the average tem- 

 perature (taken from the school records) of the 

 three months of winter with the three months of 

 spring should be made, and the fact that more 

 heat is now being received from the sun should be 

 demonstrated in this way. 



6. Meteorological studies : Various Charts. See p. 317. 



7. Animal studies : see list in the previous course ; it will 



probably be found that the aquarium will provide 

 abundance of material for animal studies at this 

 season of the year. 



* Teachers who wish to carry out experimental work on seeds and 

 seedlings will find many useful suggestions in Cavers' Plant Biology, 

 or in the same author's Life Histories of Common Plants (Clive). 



