Electricity: Learning goals

Electricity is based on electric charges.

There are two kinds of charges: positive and negative. Matter is made up of lots and lots of both kinds of charges.

Positive and negative charges together cancel each other out, so matter can have lots of electric charges but be neutral (uncharged) overall.

There are forces between charges.

• Opposite charges attract (pull together). Positive and negative attract.

• Like charges repel (push apart). Positive and positive repel. Negative and negative repel.

Rubbing certain things together, like a balloon and wool, transfers some charge from one to the other, so that they become oppositely charged. This is called static electricity (charges that don't move).

Electric current is created when electric charges move along a wire. This electric current is very useful because it can move energy from one place to another and do many valuable tasks.

Lightning is an electric current. It is created by the flow of charge between clouds and earth, which happens when they become oppositely charged.

Conductors (mostly metals) allow the flow of electric charge. Insulators (e.g. wood, paper, ceramics, plastics, stone) do not allow the flow of charge.

To work, electric devices need a circuit, which is a conducting loop that allows the current to flow in a continuous circle.

Batteries push electric charges through a circuit. They store electrical energy as chemical energy, and the current carries that energy to such things as lights, heaters, and motors. These devices change electrical energy into some other form of energy, such as heat, light, and mechanical motion.

Performance tasks:

• the student is able to build a circuit a light a bulb with a battery.
• (5-6) the student is able to identify, draw, and build a circuit with two lights in series and a circuit with two lights in parallel.
• the student is able to create static electricity and explain where there are extra charges on each object.