Presentation on theme: "What is an electric charge? An electric charge is the electrical property of matter that creates a force between objects. the attracting or repelling behavior."— Presentation transcript:
What is an electric charge? An electric charge is the electrical property of matter that creates a force between objects. the attracting or repelling behavior of a material. the attracting or repelling behavior of a material.
What is an electric charge? To create this charge, electrons must move from one atom to another.
What is an electric charge? All matter is made up of atoms Atoms are made up of smaller particles called protons, neutrons and electrons.
Why do objects become charged? An imbalance of its protons and electrons occurs An imbalance of its protons and electrons occurs Protons positive Protons positive Neutrons neutral Neutrons neutral Electrons negative Electrons negative
Conservation of Charge Electrons are bound more tightly to some atoms and molecules than others. When an electron is transferred, it creates an ion.
Conservation of Charge A charged atom is an ion. positive ion – atom loses electrons positive ion – atom loses electrons negative ion – atom gains electrons negative ion – atom gains electrons Charge is always conserved – never created or destroyed!
ELECTRICAL CONDUCTORS Conductors allow electrons to flow Conductors allow electrons to flow Conductivity depends upon how tightly the atom holds on to its electrons. Conductivity depends upon how tightly the atom holds on to its electrons. loose electrons in a material conduct the electric charge through (metals). loose electrons in a material conduct the electric charge through (metals). Examples of conductors: Metal, graphite, etc.
In solid conductors, the electrons carry the charge through the circuit because they are loosely held. In fluids, like those in a car battery, positive and negative ions and electrons may compose the flow of electric charge. ELECTRICAL CONDUCTORS
ELECTRICAL INSULATORS Insulators DO NOT conduct electricity well!! They provide RESISTANCE to the flow of electrons. RESISTANCE IS CAUSED BY INTERNAL FRICTION Examples of Insulators: Glass, wood, rubber, etc.
SEMICONDUCTORS Semiconductor – material made to behave sometimes as insulators and sometimes as conductors (germanium and silicon).
How can objects become charged? Charging by Contact – 1) Two objects are rubbed against each other and electrons are transferred. PROTONS NEVER MOVE from one atom to another.
How can objects become charged? 2) A charged object touches a neutral object, transferring electrons – PROTONS NEVER MOVE from one atom to another
How can objects become charged? Charging by Induction (charging at a distance) – A charged object is held near a neutral object and causes an overall charge.
Charge Polarization When charges rearrange in an atom, one side becomes slightly more positive and the other side becomes slightly more negative. The atom is electrically polarized. Ex – charged comb attracting bits of paper or charged balloon sticking to the wall.
Electric Fields An electric field surrounds every electric charge and exerts the force that causes other electric charges to be repelled or attracted. Electric fields are represented by arrows that show how the electric field would make a positive charge move.
Charges Exert Forces Unlike charges attract each other (positive and negative) Like charges repel each other (positive to positive or negative to negative)
Charges Exert Forces Just like gravity, the amount of electrical force exerted on an object is related to the following: 1. Distance from the charged object 2. Strength of the charge on the charged object
What is an electric charge? Protons are positive and are found in the nucleus of the atom Neutrons are neutral and found in the nucleus of the atom Electrons are negative and are found in regions around the outer edges of the atom