6. Intro to Electricity The Forces in Creation - Part 2 Text: Module 12 pages Reading Assignments Module 12 pp Module 12 pp Homework Assignment Module 12 Study Guide Questions p 310 # 1-10 Module 12 Study Guide Questions p 311 # 1-20

Introduction (p 284) The electromagnetic force is a fundamental force due to the movement interactions of the charges associated with electrons. James Maxwell (p ) –Discovered and proved that electricity and magnetism were caused/governed by the same force now called the electric force. –also act as transmission media for sound. ALL waves excerpt for one (electromagnetic waves) requires a medium - something to move through.

Two General Type of Waves (p 353) Transverse - wave that propagates perpendicular to its direction of occultation. Longitudinal - waves that propagates parallel to its direction of occultation. –Compression - area of compression (higher pressure/greater density) - like crest –Rarefaction - pulled apart lower pressure/lower density - like trough.

Some Specific Types of Waves

Photon explanation of the inverse square law. (Page 291)

The Electromagnetic Force (p ) Likes charges repel Opposite charges attract Rules of EM force (p 289) All EM charges either attract or repel each other Likes charges repel Opposite charges attract The force is directly proportional to the amount of electrical charge on each object The force is inversely proportional to the square of the distance between the two objects. F = Kq1q2/r2

Experiment 12.1: Electrical Attraction and Repulsion (p 286) Photons and the Electromagnetic Force Electromagnetism has a due nature - it can act as wave and a particle. We don't understand this because logically (deductive logic) a particle can't be a wave and a wave can't be a particle. A wave should be the movement of energy through some medium (bunch of particles). But light violates this rule in that it sometimes acts as a particle and sometimes act as wave. In this section we will look at Electromotive force in terms of particle called photons. Photon - small packet of "light" that acts like a particle. Review the EM spectrum to reinforce that we only see a small part of the EM spectrum. Radio - Microwaves Infra red Red - Yellow - Green - Violet Ultra violet X-rays, Gamma rays

How Objects become Electrically charged. (P ) Separation of Charges (p ) Charging by conduction - charging by contact with another charged object Charging by induction - charging with direct contact (inducing the charge)

Experiment 12.2 Making and Using and Electroscope (p292)

Electrical Circuits (295) Electrical Circuit: a set of wires that can conduct electricity - allow electrons to flow. Review atoms and molecules - concept of a metal and a sea of electrons. Electrical Currents: The amount of charge that passes a given point of a electrical circuit Conventional drawing of a current - why it is done backwards from electron flow. Electrical Current terms Amperage - rate of flow of current (think of the volume of water in a river)

Voltage - the change in potential energy across two points of a circuit (sometimes also called electric potential difference or electrical tension). It can be thought of in terms of the rate of change in the river elevation. You may have heard the expression it is not the voltage but the amperage that kills you. Think of a waterfall - if the water fall is very high (high voltage) but has a trickle of water (low amperage it wont hurt you) (It is the potential similarity of electrical potential between two points of an electrical or electronic circuit, expressed in volts. It measures the potential energy of an electric field to cause an electric current in an electrical conductor. Depending on the difference of electrical potential it is called extra low voltage, low voltage, high voltage or extra high voltage.

Resistance (p 300) - The ability of a substance to impede electrical flow. Metal good conductors, poor resistors Plastic good resistor, poor conductor. Concept of heating element - little bit of both.

Experiment 12.3 Current and Resistance

Switches and Circuits (p 302) Open versus closed circuit Series and Parallel Circuit Series - one goes out all goes out Parallel - one goes out other stay on.

Magnetism (p 305) Movement of charge particle produce a magnetic force Instead of positive and negative charges, we have north and south poles The north pole of a magnet attracts electrons. The south magnetic pole repels electrons. (complicated because electrons both move forward (translate) and spin (rotate) Like poles repel and opposite poles attract. Terms of magnetism: –Dipole (versus monople) –Magnetic filed lines –Magnetic filed of the earth.

Permanent Versus Induced Magnets "permanent" magnet is one which stays magnetized for a long time, such as magnets often used in refrigerator doors. Permanent magnets occur naturally in some rocks, particularly lodestone, but are now more commonly manufactured. Induced Magnets are "soft" or "impermanent" magnet is one which loses its memory of previous magnetizations. "Soft" magnetic materials are often used in electromagnets to enhance (often hundreds or thousands of times) the magnetic field of a wire that carries an electrical current and is wrapped around the magnet; the field of the "soft" magnet increases with the current.