To make a kaleidoscope, get three rectangular strips of glass 15 cm long and 4 cm wide each. Join them together to form a prism. Fix them with a few thick chart papers in a slightly long circular tube. Close one end of the tube by a cardboard disc having a hole in centre. At the other end touching the mirrors fix a circular plane glass sheet. Invert the tube and place some broken small pieces of coloured bangles on the glass plate. Close this end of the tube by a ground glass plate.