If small pieces of tissue paper are brought near to the charged glass rod, it will be found that they will be attracted to it. In fact, they will jump up to the glass rod. Similarly, a stick of sealing wax rubbed with silk will attract small pieces of tissue paper. Should a stick of sealing wax “charged” be suspended in balance by a silk thread and the charged glass rod brought near to it, the sealing wax will be attracted by the glass rod. See Fig. 1(A). Two charged bodies may attract each other.
Instead of a glass rod, a rod of charged sealing wax is brought near the suspended stick of sealing wax With this arrangement, we will find the suspended sealing wax stick is thrust away. See fig. 1(B).
Fig. 1
Two charged bodies may repel each other. In this case, both sticks of sealing wax obviously contain the same kind of charge, from which the following laws apply to electrostatic charges.
Like charged bodies repel each other. (See Fig. 2)
Unlike charged bodies attract each other. (See Fig. 3)
This action demonstrates that there are two kinds of electric charges, to which the names positive (+) and negative (-) have been applied.
ELECTRON THEORY APPLIED TO CHARGES
The charges on bodies and many other electrical phenomena may be explained by the electron theory.
An atom is the smallest part into which matter may be divided by chemical means. An electron is a minute particle of negative electricity, and represents the smallest known particle of matter. Normally an atom has enough electrons collected
