196 LABORATORY LESSONS IN GENERAL SCIENCE 



(d) A diagram to show the relative distances of the planets 

 from the sun. 



i 



I --7 



*--.ae 



--VU.ouo.ooo 



2,775,000,000--' 



FIG. 88. Distances of the planets from the sun. 



(e) The views concerning the universe held by the ancients. 

 The knowledge Columbus had of the earth's size and form. 



\ 



FIG. 89. Periods of revolution of the planets (length of their years). 



(/) The distance from sun to earth. The time required 

 for light to traverse that distance. The time required for 



FIG. 90. It is calculated that the earth receives about one two-billionth 

 of the heat and light given off by the sun. 



