14 FIRST TEAR SCIENCE 



good way to do this is to carry a ball around a bright 

 light and observe what part of the surface is illuminated 

 in the different positions. 



THE PHASES OF THE MOON. 

 Showing roughly the positions of the sun, moon, and earth. 



Summary. We have seen that the earth is one of 

 eight planets which revolve about the sun. The sun and 

 the bodies revolving around it comprise the solar system. 

 The fixed stars, which we see only at night because of the 

 great brilliancy of the sun in the daytime, are suns and 

 may like our sun be the centers of separate solar sys- 

 tems. 



Everything in the universe is composed of matter, which 

 has certain definite properties, like extension, inertia, gravi- 

 tation, and so on. The action of some of these properties 

 maintains the relation of the different heavenly bodies 

 keeps the earth revolving around the sun and the moon 

 around the earth. 



The sun and the moon have more influence upon the 



