84 



N 

 (b) Relation to animals, plants, feoil, and medium for transpor- 



tation. 

 1. Pressure of Liquids. 



(a) Presses downward and 



With a nail make a row of h^les near the bottom of a baking 

 powder can; fill with wa"ter. Compare streams issuing 

 from holes. Make a rowW small holes and row of larger 

 holes down the side of ^similar can; fill with water. 

 Compare streams from thr^e sets of holes. 



(b) Pressure upward and in every Direction. 



(1) Press glass down in a vessel of water v 



(2) Partly fill a jar with wat^r; float a circular piece of 



cardboard on the surface of the water. Place the 

 large end of an argand lan>P chimney on the card and 

 press down. What supports the card? Carefully 

 pour water into the chimney- Compare the height o f 

 the water in chimney and jar when the card floats 

 away. ^ 



(c) Buoyancy of liquids. 



(1) Buoyancy of water. 



(a) Corks in water; buoys; life bo^ts, preservers. 



(2) Buoyancy of salt water. >v. j0 uous 



(a) Learning to swim in fresh and salt l ^ eav age; 



(b) Put an egg in a jar of water; it 



Through a tube or funnel pour stron^ uar t z \ater 

 to the bottom of the jar. What makt egg 



change position? Stir the water. Wha ses 

 the egg to rise to the top? IJO , 



(3) Bouyancy of mercury, salt and fresh water. 



(4) Specific gravity. 



(a) Floating vessels and icebergs. 



(b) Oil on water; cream on milk. 



2. Water as a Solvent. 



(a) Action on salt, sugar, alum, soda, etc. 



(b) Uses of water dependent upon solvent power. 



(1) Formation of caves and springs. 



(2) Assimilation of minerals by plants. 



(3) Lime in solution in ocean and rivers used by coral and 



shell animals. 



3. Water as Vapor. 



(a) Evaporation. Effect of heat upon evaporation; heat at dif- 



ferent times of day; seasons; zones. 



(b) Condensation. Fog, mist, clouds, rain, steam. Relations. 



Effect of cold upon vapor. Condensation in different lati- 

 tudes and altitudes. 



