Galvanic cell call a chemical source of current. It is possible to make the battery giving necessary tension for power supply of the electric device of several such elements. The simplest galvanic cell is called still Callot's element. It is possible to make it in house conditions or in school laboratory.
It is required to you
- - glass glass or bank;
- - copper wire or lead plate;
- - strip or a core from zinc;
- - water;
- - table salt;
- - little sulfuric acid;
- - copper vitriol;
- - voltmeter or tester;
- - measured chemical ware;
- - scales;
- - metalwork tools.
Instruction
1. Smooth out a copper wire to gloss. It can be done file or emery paper. Twist from it any concentric spiral with a diameter slightly less than diameter of bottom of a glass. Put a spiral on a bottom, and remove the free end above edge of a glass.
2. Cut out a strip which length is 1-2 cm more than glass height from zinc. Bend it so that it could hang on the edge of a glass, and other its end which is in a vessel would not get to the bottom and the copper electrode lying on it approximately on 1 cm.
3. Prepare 10% solution of table salt. When salt completely is dissolved, add 3-4 drops of the concentrated sulfuric acid. Pour in solution in a glass with electrodes.
4. Pour into a glass a small amount of crystal copper vitriol so that it formed a thin layer (1-2 mm) on a copper electrode. Solution has to have an appearance of transparent liquid. The top part it remains colourless, and lower is painted in dark blue color.
5. Take the measuring device (the laboratory voltmeter, a tester whether avometr a multimeter) and connect it by means of clips ""crocodile"" to electrodes of a galvanic cell. At the same time connect a zinc electrode to the terminal with marking "" -"", and copper, respectively, to ""+". Callot's element develops the EMF equal to 1 V, and has internal resistance about 2-3 Ohms. Such elements can be collected in the battery giving tension sufficient for power supply of the transistor receiver, a small small lamp and other small devices.