The batteries.

The first battery was made by Alessandro Volta in 1799. This was a series of pairs of discs of zinc and copper, separated from each other by pieces of cardboard or felt impregnated water.
The battery more used is a battery Lenclanché. This battery was formed by a solution of ammonium chloride in which electrodes are immersed zinc and coal, cover for a paste of manganese dioxide and carbon dust.
The Batteries are a primary generator. This energy is accessible through two terminals that have the battery, called poles, electrodes, or terminals. One is the positive pole or the other is anode and the negative terminal or cathode. The fundamental structure of a battery consists of pieces of two different metals brought into a liquid conductor of electricity.

MELANOMA

It is a non infectious and cell proliferation disease. There are two types: the malignant melanoma or melanocarcinome and the benign melanoma or pigmentary nevus.
The risk factors in the melanocarcinome are: sunbathing in excess and without solar protection, contact with UVA and UVB rays, suffering important sunburns frequently in the infancy, a family history with this disease or having many spots. The pigmentary nevus disease is congenital.
The treatments for the melanocarcinome are surgery, chemotherapy, radiotherapy and immunotherapy and for the pigmentary nevus plastic surgery.
To prevent this disease you must protect yourself from the sun, UVB and UVA rays, use sunglasses and hats. You mustn’t sunbathe from 12h to 17h. You must supervise the growth of the spots because they can be malignant.
There is a ruler called A,B,C,D for checking the melanomas: Assymetry of their edges, Irregular Border, Different Colour and Diameter superior to 6 mm.