diagram of the ripple tank is featured in figure 2. 



A Graphic-View camera was used in all the ripple tank 

 studies. After a series of experiments, it was determined that 

 an exposure of l/lOO seconds and an aperture opening of F4.5 

 was best suited for freezing the motion. In processing the 

 pictvires, the wave crests appear as dark bands on the negative 

 and as bright bands on the positive, or actual photograph. 



Chapter I. Discu ssion of the Equation of Wave Motion 



3. Fundamental concepts 



In a non-dispersive medium, that is, a medium in which the 

 velocity of the waves is independent of the period, consider a 

 disturbance <p , which is propagated along the x-axis with a velo- 

 city c. When t = 0, cp is some function of x, f(x), which is the 

 wave profile of the disturbance (<p) plotted against x. At t = 0, 

 the curve obtained will be cp = f(x). If we suppose that the dis- 

 turbance is propagated without change of shape, then at some 

 later time, t, the curve will be identical with that at t = 0, 

 except that the profile has moved a distance ct in the positive 

 direction of the x-axis. If a new origin is taken at x = ct and 

 if distances measured from this origin are called X, so that 

 X = X + ct, then the equation of the wave profile referred to 

 the new origin would be 



9 = f (X) (3.1) 



Referred to the fixed origin, this means that 



cp = f (x - ct) (3.2) 



This is the most general expression for a wave moving with 



8 



