"Capillary attraction takes place because of the adhesive force between the liquid and the sides of the glass tube. This adhesive force draws the particles of water upwards and makes them adhere to the sides of the tube.""But you have not told us yet, Fred," said Mr. Wilson, "what all this has to do with the absorbing power of porous bodies.""I am coming to that now, sir," said Fred. "Every pore in a porous body is really a little tube, and the liquids areabsorbed into the pores by capillary attraction, just as the colored liquid rose in the capillary tube.""That"s capital," said Mr. Wilson. "You"ve mastered this matter well, Fred. Remember, it is the same capillary attraction that raises the oil in the lamp wick for the supply of the flame; it is the same capillary attraction that emptied the tumbler of water when you hung the piece of loose wick over the edge of the glass; it is the same capillary attraction that allows the soil in the flowerpot to suck up water from the saucer in which it is placed."Lesson 06
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