# PS.11 - Electricity & Magnetism

The student will investigate and understand basic principles of electricity and magnetism. Key concepts include
a) static electricity, current electricity, and circuits;
b) relationship between a magnetic field and an electric current;
c) electromagnets, motors, and generators and their uses; and
d) conductors, semiconductors, and insulators.

### BIG IDEAS

• Electricity is a form of energy that makes many modern conveniences possible.
• Energy exists in many forms and has the ability to do work or cause a change.
• Magnets show predictable behavior, making them useful tools in a variety of ways-- medicine, transportation, music, etc.'

• I can explain why my clothes sometimes stick to me, especially in the winter.
• I can explain how electricity helps a recycling center sort metals.
• I can explain why, sometimes, when one light in a set goes out, they all go out.
• I can determine safe steps for working with electricity.

### UNDERSTANDING THE STANDARD

• Several factors affect how much electricity can flow through a system. Resistance is a property of matter that affects the flow of electricity. Some substances have more resistance than others.
• Friction can cause electrons to be transferred from one object to another. These static electrical charges can build up on an object and be discharged slowly or rapidly. This is often called static electricity.
• Electricity is related to magnetism. Magnetic fields can produce electrical current in conductors. Electricity can produce a magnetic field and cause iron and steel objects to act like magnets.
• Electromagnets are temporary magnets that lose their magnetism when the electric current is removed. Both a motor and a generator have magnets (or electromagnets) and a coil of wire that creates another magnetic field.
• A generator is a device that converts mechanical energy into electrical energy. Most of the electrical energy we use comes from generators. Electric motors convert electrical energy into mechanical energy that is used to do work. Examples of motors include those in many household appliances, such as blenders and washing machines.
• A conductor is a material that transfers an electric current well. An insulator is material that does not transfer an electric current. A semiconductor is in-between a conductor and an insulator.
• The diode is a semiconductor device that acts like a one way valve to control the flow of electricity in electrical circuits. Solar cells are made of semiconductor diodes that produce direct current (DC) when visible light, infrared light (IR), or ultraviolet (UV) energy strikes them. Light emitting diodes (LED) emit visible light or infrared radiation when current passes through them. An example is the transmitter in an infrared TV remote or the lighting course behind the screen in an LED TV or notebook computer screen.
• Transistors are semiconductor devices made from silicon, and other semiconductors. They are used to amplify electrical signals (in stereos, radios, etc.) or to act like a light switch turning the flow of electricity on and off.

### ESSENTIALS

In order to meet this standard, it is expected that students will

a) design an investigation to illustrate the effects of static electricity.

construct simple circuits to determine the relationship between voltage, resistance, and current.

b) explain the relationship between a magnetic field and an electric current.

c) construct and compare series and parallel circuits.

create an electromagnet and explain how it works.

compare and contrast generators and motors and how they function.

identify situations in everyday life in which motors and generators are used.

d) provide examples of materials that are good conductors, semiconductors, and insulators.

identify current applications of semiconductors and their uses (e.g., diodes and transistors).

### KEY VOCABULARY

static electricity, current electricity, series circuit, parallel circuit, magnetic field, electric current, motor, generator, voltage, resistance, current, direct current, electromagnet, conductor, alternating current, insulator

Updated: Jun 29, 2018