A. - Electrification contact
You can load a body with only touch it with a previously loaded. In this case, both are the same typeof load, ie if I play a neutral body with another positively charged, the first is also positively charged.
B. - Electrification by friction
Rubbing twoelectrically neutral bodies (number of electrons = number of protons), both are charged, one positively charged and one negatively charged.
If you rub a glass rodwith a silk cloth, there is a transfer of electrons from the glass to silk.
If you rub a pencil of pasta with a woolen cloth, there is a transfer of electrons from thecloth to the pen.
C. - .- Electrification by induction
An electrically charged body can attract another body that is neutral. When approaching an electrifiedbody to a neutral body, establishing an electrical interaction between the charges of first and neutral body.
As a result of this relationship, the initialredistribution is altered: the charges with opposite sign to the charge on the electrified body approach to it.
In this process of redistribution of loads, the initial netcharge has not changed in the neutral body, but in some areas is positively charged and other negative
We say that electric charges are induced. Then the electrifiedbody induces a charge of opposite sign in the neutral body and therefore it attracts
An electroscope is a device that can detect the presence of a charged object exploiting the phenomenon of separation of charges by induction.