The product is composed of teaching board, magnetic block and chemical device. Demonstration board 38, for the production of white plastic plate with 3mm thickness, the size is 80 * 45mm, the teach board back embedded two blocks with 4 * 2mm magnets, each magnet surface magnetic induction intensity is less than 20GS; 38 kinds of chemical device schematic plan printed on the demonstration board, respectively. A series of "1 to 38" serial number.