Construction of a kaleidoscope:
Three rectangular mirror strips of dimensions 15cm x 4cm (l x b) are joined together to form a prism (Fig a).
This prism is fixed inside a circular cardboard tube where the length of the circular cardboard tube should be slightly longer than the prism (Fig b).
This circular tube is now closed at one end with a cardboard disc and the disc has a hole in it through which we can see the inside of the tube(Fig c).
At the other end of the circular tube, a plane glass plate is fixed in such a way that this glass plate touches the prism mirrors. Several small and broken pieces of coloured glass are put in this glass plate. This end is then closed by a round glass plate allowing enough space for the coloured glass pieces to move (Fig d).