94 L AB OR A 7 'OR Y G UIDE IN PH YS/OLOGY. 



3. Operation. Mark upon the side of the reservoir a point 

 36 cm. above the center of the nozzle, also a point 64 

 cm. above the nozzle. While the reservoir is filled from 

 one flask the water may be caught in the other. As- 

 sume some convenient unit of time, as 10 or 15 seconds. 

 4.. Observations. (a) Fill the reservoir to the height of 64 



cm. 



Allow the water to flow from the nozzle freely into the 

 flasks. Observe the force with which the jet issues 

 from the nozzle when the water begins to flow. Note 

 the difference when the water in the reservoir reaches 

 the 36 cm. mark; the 16 cm. mark. What are your 

 conclusions? 



(<) Velocity. How does the velocity of the discharge 

 vary with the varying height of the column of water ? 

 Why does it so vary? Does it verify the law of 

 Torricelli? The rate at which a fluid is discharged 

 through an orifice [better a nozzle] in a reservoir is 

 equal to the velocity which would be acquired by a body 

 falling freely through a height equal to the distance be- 

 tween the orifice and the surface of the fluid. 



Recall the law of falling bodies. How far will a 

 body fall in vacuo,\}\e first, second and third seconds 

 respectively? What is the constant acceleration 

 per second, due to gravitation ? What is the 

 velocity at the end of the first, second and third 

 seconds respectively? What is the total distance 

 traversed at the end of the first, second and third 

 seconds respectively? Let g equal the constant 

 acceleration (approximately 32 ft. or 981 cm). Let 

 h equal the total distance in centimeters, v the 

 velocity and t the time in seconds. Derive from 

 the facts the following equations: 

 (1) v = gt. 



CO h = g 



