Section 9.2 The Electrical Nature of Matter
Rubbing items together does not create electrical charges. The charges were already
there!
STATIC ELECTRICITY refers to the buildup of electric charge on the surface of objects.
The static charges remain on an object until they either bleed off to ground or are
quickly neutralized by a discharge
The study of static electric charge is called ELECTROSTATICS.
The Law of Electric Charges:
“Like charges repel one another, and unlike charges attract one another.”
Charged objects will also attract neutral objects. (comb and paper demo)
Balloon & Water video…
A MODEL FOR THE ELECTRICAL NATURE OF MATTER
1. All matter is made up of submicroscopic particles called atoms.
2. At the center of each atoms is a NUCLEUS, with two kinds of particles: the
positively charges PROTON and the uncharged NEUTRON. Protons do not move form
the nucleus when an atom becomes charges.
3. A cloud of negatively charged particles called ELECTRONS surround the nucleus. An
electron has the same amount of charge as a proton, but the kind of charge is
opposite. When atoms become charged, only the electrons move from atom to
atom.
4. Like charges repel each other; unlike charges attract each other.
5. In some elements, such as copper, the nucleus has a weaker attraction for its
electrons than in others, and electrons are able to move freely from atom to atom.
IN other elements, such as sulphur, the electrons are strongly bound to each atom.
6. In each atom, the number of electrons surrounding the nucleus equals the number
of protons in the nucleus. A single atom is always electrically neutral.
7. If an atom gains an extra electron, the net charge on the atom is negative, and it is
called a NEGATIVE ION or ANION. If an atom loses an electron, the net charge on
the atom is positive, and it is called a POSITIVE ION, or CATION.