XY. ICE 



Material. — When the weather is freezing cold, place some cups and 

 bottles of water outside of a window on the sill. Tip them frequently so 

 as to see the first ice that forms. 



Observation. — Look at tlie freezing cup of water. 

 On what part of the surface does the first ice form ? 

 How many pieces of ice form at one time ? What is 

 the size of the first bits of ice that you see ? What 

 is their shape ? Is the ice tlie same in all the cups ? 



Just before the cup is frozen over pour off the 

 water. Do you find any particles of ice on the sides 

 of the first bits of ice that formed ? Is the under sur- 

 face of the ice smooth ? What do you find on the 

 under surface ? Is the upper surface of the ice per- 

 fectly level, or does it show tiny ridges ? How are 

 the ridges made ? 



Look at the freezing bottle of water. Where 

 does the first ice appear in the bottle ? What is 

 the shape of the ice ? How far into the water do 

 the first pieces of ice reach ? 



Drawing. — Draw a picture of the first particles of 



ice that you saw on the freezing cup of water. Draw 



a picture of the first ice that formed in the bottle of 



water. 



73 



