LIQUIDS AND THEIR PROPERTIES 



91 



does not rise higher in tubes than in the surrounding liquid, 

 as water does, but is slightly depressed. 



Small spaces between threads close together, as in a wick 

 or cloth, have the effect of 

 tubes in which liquid rises. 

 If a dry cloth is placed with 

 one end in water, the liquid 

 rises in the spaces, as in 

 tubes, and the cloth is 

 soon dampened throughout. 

 Water sometimes rises 

 through the cloth over the 

 edge of a bowl and drops 

 from the other end of the 

 cloth. Kerosene rises be- 

 tween and upon the threads 

 of the lamp wick to the top, 

 where it burns. Blotting 

 paper takes up ink be- 

 tween the fibers of the 

 paper. In plants, capillar- 

 ity aids in the rise of liquids 

 from the roots through the 



FIG. 41. CAPILLARITY 



The smaller the bore of a tube, 

 the higher a liquid will rise by capil- 

 larity. The diameter of the tube 

 shown here is 2 mm., which is much 

 larger than that of many plant cells. 

 Liquids pass from cell to cell by 

 osmosis, and rise in the cell by 

 capillarity. 



stems to the leaves. In soil, 



it aids in the rise of water from lower levels to the surface 



of the ground. 



EXERCISES 



1. Which would be likely to furnish cooler water, a hillside spring 

 or a fissure spring? Why? 



2. At what depth in fresh water will the pressure be 75 g. per square 

 centimeter? 



3. Why is pressure in the ocean greater than at the same depth in 

 a pond? 



4. Which apparently loses more weight, a body partially immersed 

 in water or a body wholly immersed? Why? 



60 A cubical block 5 cm. on each edge is immersed in water to a 



