PDF chapter test TRY NOW

Open a water tap. Adjust the flow so that it forms a thin stream. Charge a refill. Bring it near the water stream. Observe what happens. Write a short report on the activity.
  
a. The sound returns to being , when we take the tumbler out of our mouth.
 
b. When we try to suck air in, we notice that sound gets  than it did earlier.