Gravity, Electricity, & Magnetism S8P5. Students will recognize characteristics of gravity, electricity, and magnetism as major kinds of forces acting in nature.

Enduring Understandings Students will understand that: Electric forces arise from the movement of electrical charge. Magnetic forces arise from the movement of electrical charge. An electric circuit allows electrons to flow from a negative pole to a positive pole.

Series and parallel circuits can be used to control the amount of electric energy produced. Every object exerts gravitational force dependent upon its mass and distance from other objects.

Gravity The force that attracts all objects toward each other. Gravity depends on two factors: Mass of objects Distance between objects

Mass Amount of matter in an object Weight Force of gravity on an object

Electricity The collection or flow of electrons in the form of an electric charge. Electrons are a negatively charged particle located outside the nucleus of an atom.

Static Electricity Is the charge that stays on an object. Unlike charges (+,-) attract each other, and like charges (+,+), (-,-) repel each other.

Materials affect charge movement Conductors- a material that allows an electric charge to pass through it easily. Examples: iron, steel, copper, & aluminum Insulators- a material that does not allow a charge to pass through it. Examples: plastic & rubber

Electric Current The steady flow of electricity. A current will move along a wire or a path called a circuit. Circuit means “to go around.” There are two types of circuits Series Circuit Parallel Circuit

In which direction does the current flow? From the Negative terminal to the Positive terminal of a cell.

Types of Circuits Series Circuit is a circuit that has only one path for the current. Parallel Circuit is a circuit that has more than one path for current to travel.

Short Circuits An unintended path connecting one part of a circuit with another. A short circuit will cause large amounts of current to flow in a circuit and overload the circuit. They are very dangerous. The wires on a circuit can melt and then cause a fire.

Magnetism A push or pull exerted by a magnet. There are two poles. North South If you cut a magnet in half, you do not separate one pole from the other. Both pieces will have two poles.

Opposites attract Like poles push away from each other.

Magnetic Field The area surrounding the magnet is the magnetic field. Where the lines are the closest, the magnetic force is the strongest.

Electricity & Magnetism Passing a current through a piece of wire causes a magnetic field to form around a wire (electromagnetism). The strength of the magnetic field could be greater if you put a piece of copper inside the wire. This is called an electromagnet.

Electromagnets Their magnetism can be turned on or off. Stopping the flow of electric current through the wire coil stops the magnetic field. How do we change the strength of the electromagnet? To INCREASE To DECREASE Increase the strength of the current Decrease the strength of the current Add more coils of wire Use fewer coils of wire Increase size of iron core Decrease size of iron core