EXERCISE 2 

 TAX AIR BE MADE TO EXCLUDE WATER? 



Materials. Those of Exercise ;1 :, also a short glass tube, or straw bent slightly at one end, or 

 piece of rubber tiiting. 



Directions. I' hire the drmkinjg.'g.lass under the water so that it is full of water. Then invert the 

 glass so that the mouth is downward. With the straw or tube placed with the bent end directly 

 under the mouth of the glass, blow through the tube. Explain what occurs. 



Additional problem. Why is it that when a heavy rain falls after a long period of dry weather air bubbles 

 arise from the soil ? 



[2'] 



