Chapter 15: Electricity

Lesson #1

What are the effects of moving charges?

  1. Current – The flow of electrical charges thorough a material.
  2. Conductor – A material through which an electric charge can move easily. (Examples of good conductors: Copper, gold, silver, and aluminum. Graphite and salt water can conduct electrical current).
  3. Resistor – A material that resists the flow of an electrical charge.
  4. Insulators – Are such strong resistors that they stop most electrical currents. (Examples: Rubber, glass, plastic, and dry cotton.)
  1. Some materials allow electric charges to flow easily, while other reduce or stop the flow.
  2. An object that loses an electron, gains a positive charge. An object that gains an electron, gains a negative charge. This is electricity.
  3. Moving charges are found in electrical currents in wires.
  4. Conductors have electrons that are not tightly bound to their atoms.
  5. As a current moves through a resistor, some electrical energy changes to thermal energy. (Example: Toaster).
  6. A superconductor has no resistance to electrical current. Many metals and ceramics can become superconductors but only at super-cold temperatures.

Lesson #2

What are simple currents?

  1. Circuit diagram – A map of a circuit.
  2. Volt – (V) A measure of the electrical force provided by an energy source.
  1. An electrical current can travel in a circuit, or loop, to power electronic devices.
  2. A simple circuit contains a source of energy (usually a battery) and at least on conductor. (It may also include at least on switch, which opens or closes the gap in the circuit).
  3. A series circuit is a circuit with more than one resistor on a single wire.
  4. Insulators help keep the electric charges inside the pathway.
  5. Resistors can transform electrical energy into: sound, light, thermal, or mechanical energy.
  6. Symbols on a circuit diagram stand for each part of a circuit. (Examples: Wire, battery, open switch, closed switch, resistor, and wall outlet.)
  7. The Ohm () is the unit of measure for resistance to electrical current.
  8. Current is a measure of how much charge moves past a given spot each second. The unit for measuring current is ampere (A) often called amp.

Lesson # 3

What are complex circuits?

  1. Electromagnet–Magnets that carry an electrical current.
  1. A parallel circuit has more than one branch or pathway. Not all branches need to be on at the same time. Some circuits have hundreds or thousands of circuits. Computers have the most complicated circuits. (Other examples: Power strip or light fixture with multiple bulbs.)
  2. Dr. Oersted discovered every electrical current produces a magnetic force.
  3. An electromagnet can become stronger by using more coils or increasing the current. You can also place a bar inside the coils to make an electromagnet stronger.
  4. An electromagnet can be turned on and off and the strength changed, a regular magnet cannot.
  5. Electromagnets are uses in motors, sound systems, cranes, and doorbells.
  1. Never touch electrical outlets.
  2. Never unplug electrical cords by yanking on them.
  3. Replace frayed cords.
  4. Never touch a downed power line. Call 911.
  5. Never touch an electrical appliance when standing in water.
  6. Never use cord-operated appliances near water.