ELECTRICITY AND MAGNETISM

ELECTRICITY AND MAGNETISM

ELECTRICITY

1.       Electricity is a form of energy produced by a flow of electrons.

2.       Electrons are negatively charged particles orbiting around an atom.

  1. An atom is the smallest indivisible particles of matter.
  2. When electrons flow, they produce electric current.
  3. An electric current is a flow of electrons.
  4. Electric current is measured in units called Amperes using an instrument called ammeter.

Forms of electricity

          There are two forms of electricity:

  1.  Static Electricity
  2.  Current Electricity

STATIC ELECTRICITY:                   

  1. In some materials called insulators, electrons don’t move. They only move when there is friction.
  2.  Electrons in insulators move from one atom and get attached to another.

3.       Static electricity is the form of electricity in which electrons don’t flow.

4.       It is usually produced when insulators are rubbed together.

5.       Static electricity has two charges. These are negative and positive charges.

6.       The positive charges are the protons and the negative charges are the electrons.

7.       In static electricity there is no continuous flow of electrons.

8.       Static electricity takes place as a result of friction in insulators.

plastic comb

LIHGTNING AND THUNDER

  1. In nature static electricity takes place in the clouds as they move rubbing against a layer of air.
  2. When a negatively charged cloud meets a positively charged cloud they form a huge spark called Lightning.
ligth

3.       The huge spark causes the air around to expand and contract immediately resulting into a loud sound called thunder.

4.       Thunder and lighting are formed at the same time but we see lightning first because light travels faster than sound.

5.       Other examples of static electricity happens after ironing a nylon cloth. When brought near the body hair it stands or sticks out.

DANGERS  OF LIGHTNING:

  1. Therefore lightning can destroy plants and animals life.
  2. Lightning can cause huge fires on houses; especially the high raised  buildings. This causes destruction of property.

PROTECTION AGAINST LIGHTNING:

  1. Place Lightning conductors on  tall buildings.

These are copper and aluminum pieces of metals which are placed on the building and are made to connect to a metal plate placed underground.

spikes or pointed ends of the metal are placed above the building to attract the charges.

 Copper or aluminium are used because they are good conductors of electricity. So they conduct the charges to the ground easily where they are neutralised.

  • Avoid standing in an open space when IT IS drizzling, as you may be the tallest material to attract the charges. This may result into being struck by lightning.
  • Avoid seeking shelter from rain under a tree because you may be struck by the charges  as they are passing through the tree.

CURRENT ELECTRICITY:

1.       This is the type of electricity whose electrons flow through conductors.

2.       Conductors are materials that allow electricity to pass through them.

3.       The flow or movement of electrons through a conductor is what is known as an electric current.

Types of Current electricity:

  • Direct Current (D.C)
  • Alternating Current (A.C)

Direct Current:

1.       This is the type of current electricity where electrons flow in one direction. They flow from the negative terminal of the source through the conductor, appliance and then to the Positive terminal.

2.       Current on the other hand flows from the Positive terminal to the negative terminal.

3.       It cannot be stepped up or down.

4.       It cannot be stored.

          Sources of direct current electricity.

  1. Dry cells
    1. Wet cell.
      1. Batteries
batteries

ALTERNATING CURRENT ELECTRICITY:

1.       This is the type of electricity where current flows in both directions. (from the source to the appliance and then back to the source).

2.       Current electricity is produced by Devices like: – Generators and dynamos

3.       It can be stored.

4.       It can be stepped down up or down.

SOURCES OF ALTERNATING CURRECNT ELECTRICITY:

1.       The source of this type of electricity depends on the source of power which helps to turn the generators.

2.       Electricity from each source is given a name as below

      Source of energy                        Type of electricity
  i  Running water                             Hydro Electricity
  ii  Fuels                                             Thermal Electricity
  iii  Geothermal heat                            Geo thermal Electricity
  iv  Wind                                               Mechanical Electricity
  v  Nuclear power                               Atomic Electricity
  vi  Machines (Dynamos)                    Mechanical Electricity
  vii  Chemicals                                      Chemo Electricity