Electrical Conductors, Insulators, and Ways to Charge

Electrical Conductors, Insulators,

and Ways to Charge

Moving Charges

Have you ever noticed that electrical cords are often made from metal and plastic? Different materials are used because electric charges move through some materials more easily than they move through others. Most materials are either conductors or insulators based on home easily charges move in them.

Electrical Conductors

An electrical conductor is a material in which charges can move easily. Most metals are good conductors because their electrons are free to move. Conductors are used to make wires. Copper, aluminum, and mercury are good conductors.

Electrical Insulators

An electrical insulator is a material in which charges cannot move easily. Insulators do not conduct charges very well because their electrons cannot flow freely. Insulation around wires are made of insulators. Plastic, rubber, glass, wood, and air are good insulators.

Multiple Choice

What is the difference between insulators and conductors?

• Insulators allow electricity to flow easily and conductors do not.

• Conductors allow electricity to flow easily and insulators do not.

• Conductors are used only for electricity and insulators are used only for heat.

• Insulators are used only for electricity and conductors are used only for heat.

Multiple Select

Select the conductors.

• copper

• wood

• air

• mercury

• rubber

Multiple Select

Select the insulators.

• aluminum

• plastic

• glass

• steel

• diamond

Copy this chart onto page 94 of your notebook.

Electric Charge

All matter is made up of very small particles called atoms. Atoms are made of even smaller particles called protons, neutrons, and electrons.

Multiple Choice

Which is correct?

• protons are positive, neutrons are negative, and electrons are neutral

• protons are negative, neutrons are neutral, and electrons are positive

• protons are positive, neutrons are neutral, and electrons are negative

• protons are negative, neutrons are neutral, and electrons are positive

Charge It!

An object becomes positively charged when it loses electrons. An object becomes negatively charged when it gains electrons. Objects become charged by friction, conduction, and induction.

Friction

Charging by friction happens when electrons are "wiped" from one object to another. If you use a cloth to rub a plastic ruler, electrons move from the cloth to the ruler. The ruler gains electrons and becomes negatively charged. At the same time, the cloth loses electrons and becomes positively charged.

Conduction

Charging by conduction happens when electrons move from one object to another by direct contact. Suppose you touch an uncharged piece of metal with a positively charged glass rod. Electrons from the metal will move to the glass rod. The metal loses electrons and becomes positively charged.

Induction

Charging by induction happens when charges in an uncharged metal object are rearranged without direct contact with a charged object. Suppose you hold a metal object near a positively charged object. The electrons in the metal are attracted to and move toward the positively charged object. This movement induces an area of negative charge on the surface of the metal.

Find this worksheet. It is with your extra pages for unit 2.

These are not in the correct order. Label each one with an "I" for induction, a "C" for conduction, or a "F" for friction.

(you could also choose to color code them instead)

Fill in the Blank

_____ is when objects do not touch but become charged.

Fill in the Blank

_____ is when objects rub against each other to become charged.

Fill in the Blank

_____ is when objects touch each other and become charged.

Check your answers!

Cut and glue these notes onto

page 95 in your notebook.

Multiple Select

Select the two that are true.

• Insulators are usually charged by friction.

• Conductors are usually charged by friction.

• Insulators are usually charged by conduction and induction.

• Conductors are usually charged by induction and conduction.

• Conduction, induction, and friction are used to charge both conductors and insulators.