It is used as a demonstration model with an Overhead Projector. Comprises a steel frame with an acrylic window. The frame is shared to form beaches on all sides to minimize unwanted reflections & fits neatly onto an overhead projector. The undersides of the frame has threaded metal inserts to take the four legs provided enabling the tank to be used as a free standing beach model, if required. Facilities are provided for mounting the ripple tank illuminant for this purpose. A gantry is supplied for supporting a motor beam, the height of which is easily adjustable allowing it to be positioned for maximum effect. Ripples are produced by a small 1.5 to 4.5V DC motor mounted on the plastic beam of 240mm length. A standard cam is fitted to the motor spindle to give an oscillatory motion & row of nine holes in the beam are for mounting the spherical dippers for production of circular ripples.