How Electricity Works | Understanding Electricity | what is electricity for kids

How Electricity Works | Understanding Electricity | what is electricity for kids

What is Electricity?

The first question that we will find out the answer is “where does electricity come from?“.

“What are atoms?“

Electrons are bound in their orbit by attraction of protons, but electrons in the outer band can become free of their orbit by some external forces. These are referred to as free electrons, which move from one atom to the next, electron flows are produced. These are the basis of electricity. Materials that allow many electrons to move freely are called conductors and materials that allow few free electrons to move are called insulators.

“Static electricity“

Current, Voltage and Resistance

What is Current?

Wires are made up of conductors such as copper or aluminum. Atoms of metal are made up of free electrons, which freely move from one atom to the next. If an electron is added in wire, a free electron is attracted to a proton to be neutral. Forcing electrons out of their orbits can cause a lack of electrons. Electrons, which continuously move in wire, are called Electric Current.

Current is flow of electrons, but current and electron flow in the opposite direction. Current flows from positive to negative and electron flows from negative to positive.

What is voltage?

Electromotive force means the force which makes current continuously flows through a conductor. This force can be generated from power generator, battery, flashlight battery and fuel cell, etc.

Volt, abbreviated “V”, is the unit of measurement used interchangeably for voltage, potential, and electromotive force. One volt means a force which makes current of one amp move through a resistance of one ohm.

What is resistance?

The unit of measurement for resistance is ohms and its symbol is the Greek letter omega (Ω). The resistance of one ohm means a conductor allows a current of one amp to flow with a voltage of one volt.

All materials are difference in allowing electrons flow. Materials that allow many electrons to flow freely are called conductors such as copper, silver, aluminium, hydrochloric solution, sulphuric acid and saltwater. In contrast, materials which allow few electrons to flow are called insulators such as plastic, rubber, glass and dry paper. Another type of materials, semiconductors have characteristics of both conductors and insulators. They allow electrons to move while being able to control flow of electrons and examples are carbon, silicon and germanium, etc.

The resistance of conductor depends on two main factors as the followings:

1. Types of material
2.  Temperature of material

How to measure current?

Safety instructions for current measurement;

• Estimate current that required measuring then choose a suitable ammeter, since each ammeter has different limit of current measurement.
• Be sure that the connection to positive terminal (+) and negative terminal (-) of ammeter are correct.
• Do not directly connect ammeter terminals to dry cell terminals. Since it can damage the meter.

How to measure voltage?

Steps for voltage measurement
Connect a small light bulb to a dry cell. A voltmeter is wired in parallel with the light bulb to measure voltage across the light bulb. Connect positive terminal (+) of voltmeter to positive terminal (+) of a dry cell and connect negative terminal (-) of voltmeter to negative terminal (-) of a dry cell (see figure below)

Safety instructions for measuring voltage;

• Estimate voltage that required measuring then choose
  a suitable voltmeter, since each voltmeter is designed with the limit of voltage measurement
• Be sure that the connecting of positive terminal (+) and negative terminal (-) of voltmeter are correct

How to measure resistance?

Steps for resistance measurement;

• Turn the face dial to a position for required measuring, resistance, then touch both of terminals of multimeter  and adjust the meter range to 0 Ω.
• Touch both of terminals of meter to a resistance and take the reading (see figure 2).

How Electricity works?

Electric current is the ability to do work. Electric current can be converted to heat, power and magnetism.
Electric current is classified by its functions and three primary types are:

• Heat and power
• Electrochemistry
• Magnetism

Heat and power

Experiment is made by measuring heat quantity of water by calorimeter. Increase voltage across wire by the variac and connect ammeter and voltmeter to measure current and voltage.
Set the variac scale to adjust voltage and current value of nichrom wire and current is passed through periodically and measure heat quantity from nichrom wire. There are any indications of voltage and current. If voltage, current and time increase, heat quantity will also increase. They are expressed by the relation as below.

This is called Joule’s law. Heat quantity depends on voltage time current and interval of time. From Ohm’s law, V (Voltage) = I (Current) x R (Resistance) therefore

Heat quantity depends on current squared times resistance and interval of time.
When current is passed through nichrom wire in water, current is converted to heat and temperature rises. Work is done by heat generated in an electrical circuit, which is called Electric power.

Electric power is measured in Watts-hour (Wh) and heat quantity is measured in calories (Cal).

Work is done by heat generated in an electrical circuit is written in power, which it means that the rate work is done in a circuit when 1 Amp flows with 1 Volt applied and its unit of measurement is Watt.

Conclusion

Electrochemistry

Experiment is made by soaking two platinum (Pt) plates in molten salt. Connect batteries to two platinum plates, current is passed through molten salt and produces chlorine bubbles around positive plate (+) and hydrogen bubbles around negative plate (-) since sodium chloride composes of sodium (Na) and chloride (Cl). When sodium chloride melts in water, the elements are separated. Sodium has positive charges (+), while chlorine has negative charges (-) and these charges are called ions. The molten salt has both positive charges, called anodes, and negative charges called cathodes. The state of separated elements is called ionization. If salt is melted by water, solution is available ions, called electrolyte solution. And if current is passed through electrolyte solution, a chemical reaction known as electrolysis occurs.

Magnetism

What is magnetism?

The characteristics of magnet are.

•  Every magnet has two poles, one north pole and one south pole,
• Opposite poles attract each other, while like poles repel each other.

Electricity and magnetic field

When a current-carrying wire coil is placed near iron bar, the iron bar move slightly (see figure below). If core is placed in a wire coil, the iron bar is attracted strongly (see figure below). Because core is a soft iron, which conducts magnetic lines of force, when current is passed through wire coil around core, the core becomes magnetized with high power that is called electromagnets. This function is widely applied for using in industries.