- Education and Science»
Facts About electricity and batteries
What is electricity?
A Everything is made of atoms. At the centre of an atom is the nucleus made of protons and neutrons. An atom also has tiny electrons which spin around the nucleus.
Electrons have a negative electrical charge, and protons have a positive charge. The electrons don’t stay in one place. They move around to different atoms, so some atoms have more protons, some have more electrons. An atom with more protons is positively charged.
One with more electrons is negatively charged. When the electrons pass from one atom to the next, it creates an electric current. Electricity can be used or stored sford in batteries ( GP baterija ) for later use.
Who discovered electricity?
A Ancient Greeks knew that electricity could be produced by rubbing two pieces of felt together. But the first use of the word electricity was by Sir Thomas Browne in his 1646 book Pseudodoxia Epidemica (Vulgar Errors).
In 1752, Benjamin Franklin proved that lightning was created by electric charges. He tied an iron key to a kite string during a storm and showed that the lightning hit the key. For this reason, Franklin is said to have discovered electricity.
Today, we know that lightning is the most commonly seen form of natural electricity. It is caused by clouds carrying a negative charge that bump in to positively charged objects on Earth.
How do power stations generate so much electricity?
Power stations convert the kinetic energy of moving water (hydroelectricity), heat produced by burning coal (thermal electricity) or by a nuclear reaction (nuclear power), the kinetic energy of wind that turns a windmill, tide movements (tidal power) or heat from inside the Earth (geothermal power) to generate electricity.
How is electricity measured?
A Voltage is the measure of the strength of an electric current. The unit for measuring voltage is the volt.
A voltameter tells us how many electrons are sent from one end of the circuit and how many are received at the other end. The distance electricity travels affects its quality, especially if it is prevented from flowing freely because of resistance.
Resistance is a material’s opposition to the flow of electric current through it. Resistance is measured in ohms.
Scientists are always looking for materials like copper that are good conductors of electricity and have a low resistance. Silver is the best conductor, but it cannot be used in wires in our homes because it is too costly. Most metals are good conductors.
How does a light bulb work?
A The electric bulb is made of transparent or translucent glass and has a delicate wire called a filament. It has to be thin so that its atoms collide more often when an electric current is passed through it. That is how it glows.
Thomas Alva Edison made the first practical, workable bulb for home use. Compact fluorescent lamps that use less energy than other bulbs have become increasingly popular since the 1980s.
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