4 INTRODUCTION TO GENERAL SCIENCE 



heat in it than the liquid. For a given temperature matter 

 exists in only one of these conditions, although a slight 

 variation of temperature may cause it to change into another 

 state. All matter existing in the sun is so hot as to be en- 

 tirely composed of gas. 



There is one material with which we are all familiar, that 

 exists in the three states with a very slight change of tem- 

 perature. Water, above thirty-two degrees F., and below 

 two hundred and twelve degrees F., exists as a liquid; below 

 thirty-two degrees F. it is a solid; above two hundred and 

 twelve degrees F. it is a vapor. On account of the easy 

 changing from one condition to another, water is a powerful 

 agent in the transmission of energy. We shall see how the 

 freezing of water can break rocks, on account of its expansion. 

 Boiling water also exerts a tremendous pressure, and thus 

 enables us to change heat into mechanical energy. In all of 

 the explosions solids or liquids were changed into gases which 

 occupied much more space than the solids or the liquids. 

 If the space were occupied without resistance, there was a 

 rapid, but quiet, burning ; otherwise the space was occupied 

 with force, and an explosion resulted. 



References : 



1. 1304: 18-19. Air, Water, Rock. 



2. 1703 : 128. The Physical States of Matter. 



3. 1803 : 105-106. The Three States of Matter. 



a. 1201 : 126-128. Gases, Liquids, and Solids. 



b. 1314 : 6-7. The Three States of Matter. 



c. 1804 : 127-129. The Peculiar Properties of the Three 



States of Matter. 



d. 1805 : 101-105. States of Matter Explained. 



e. 1806 : 347-349. Causes of Changes of State. 

 /. 1806 : 354-355. Causes of Changes of State. 

 g. 1807 : 3-5. The Three States of Matter. 



