Science 8

What is a commutator?

A commutator reverses the current in a coil in an electric motor.

What is a step- up and step- down transformer?

A step- up transformer increases the voltage and a step- down transformer decreases voltage.

How does alternating current differ from direct current?

Alternating current differs from direct current because it reverses the direction of current flow, and direct current flows in only one direction through a wire.

What is a galvanometer?

Galvanometers are devices that use an electromagnet to measure electric current.

Lily went to Sweden with her friends for a summer vacation. Electrical outlets in Sweden are 210 volts, instead of the 120 volts that she was used to in the U.S. What would Lily need to do before she could use her Amercian alarm clock?

Lily would have to use a step-down transformer to lessen the volts, so she can use her device.

What do you think some potenetial problems might be when using windmills as a source of energy for generators?

Some potential problems of using windmills are there may not be enough wind to power the windmills, and they may break if the wind is too fast.

What is the difference between a motor and generator?

The difference between a motor and a generator is that a generator turns mechanical energy to electrical energy, and a motor turns electrical energy to mechanical energy.

What is the difference between a magnetic field and a magnetic domain?

The magnetic field surrounds the atoms that are lined up in the magnetic domain.

electric current that reverses its direction regularly and is used to run appliances

alternating current

electric current that flows through a wire in only one direction

direct current

device that converts electrical energy to mechanical enery to do work; basically has a power supply, a permanent magnet, and an electromagnet that can rotate

electric motor

tempory magnet made by placing an iron core inside a current-carrying coil of wire and whose strength can be increased by adding more turns to the wire loop or by increasing the amount of current passing through a wire

electromagnet

process in which electric current is produced by moving a wire loop through a magnetic field or by moving a magnet through a loop of wire

electromagnetic induction

instrument that uses an electromagnet to measure electric current

galvanometer

device that converts mechanical energy to electrical energy by rotating a wire coil through the magnetic field of a permanent magnet

generator

group of atoms having aligned magnetic poles

magnetic domain

region where a magnet's magnetic force is strongest; like poles repel and opposite poles attract

magnetic pole

the properties and interactiions of magnets

magnetism

device that increases or decreases alternating current generated by a power plant so that it can enter homes safely

transformer

large wheel that rotates when pushed by steam, wind, or water and that provides mechanical energy to a generator

turbine