An electric cell is device that converts chemical energy into electrical energy. It contains chemicals that undergo a chemical reaction to produce electricity. A dry electric cell contains chemicals in dry or semi-solid form.

Inner view of a dry cell: The dry cell contains a paste of ammonium chloride inside a zinc container. Inside the paste a cardboard container contains powdered manganese dioxide and carbon is placed. A carbon rod with a metal cap which acts as a the positive terminal is dipped into the manganese dioxide. The base of the zinc acts as a negative terminal. The whole thing is then sealed so that only the base is exposed. A chemical reaction takes place between ammonium chloride paste and powdered manganese dioxide.

Electric current flows in from one terminal and flows out from the other terminal. If we connect the tip of the metal cap along with the base of the zind can by a metal wire current will flow through it and a bulb can glow.

According to the video, a circuit is a route through which electrical current can flow. In the example circuit used in the video, electrons flow from the negative side of a battery to a conducting material on the base of the bulb. Then the electrons flow up a wire inside the bulb and across the filament, which is the part of the bulb that lights up. Some of the electrical energy is changed to heat and light energy as the electrons go through the filament. The electrons then continue down another small wire inside the bulb to another conductor on the base of the bulb, and finally make their way to the positive side of the battery. Importantly, there would not be a complete circuit if the electrons did not travel all the way back to the positive side of the battery, and the bulb would not light. When there is an unbroken path on which electrons flow, as in this example, it is called a complete circuit. The unbroken path that the electrons follow is called a closed circuit because electricity will only flow on an unbroken path. The light bulb will not light unless there is a closed circuit.

The video also discusses the role of insulators in a circuit. Insulators are materials that do not easily accept and pass on electrons. There is an insulator between the conductor that leads up to the filament and the conductor that leads away from the filament in a light bulb. If an insulator did not surround a wire carrying a current, it is possible for the electron flow to get directed to another conductor that comes into contact with the circuit. Electricity will follow the path of least resistance. If the electrons take a path that bypasses part of the complete circuit, it is called a short circuit.

The video identifies the parts of a light bulb and explains their functions. Here's a breakdown of the parts covered:

• Glass bulb: This is the transparent shell that houses the other components of the bulb.

• Inert gas: This gas is inside the bulb to prevent the filament from burning out.

• Tungsten filament: This is a thin wire that heats up and glows when electricity is supplied.

• Support wires: These thin wires hold the filament in place.

• Glass tab: This is a glass piece that supports the filament and the contact wires.

• Contact wires: These wires connect the filament to the electrical supply.

• Base: This is the metal screw part of the bulb that screws into a light socket.

• Insulation: This is a black material that covers the wires to prevent electrical shock.

• Terminals: These are the metal contacts at the base of the bulb that connect to the electrical supply.

The video also mentions that viewers may have questions about the materials used in the bulb and why certain designs are chosen. The creator promises to answer these questions in future videos.

chapter 1

today we learn about conductors and insulators electricity is the movement of electrons called electric current in a circuit some materials are good at passing electric current through them and others block the current these materials are known as conductors and insulators lets learn about conductors first

chapter 2

conductors are the materials which provide the easiest path to the electric current current travels smoothly through the conductors conductors provide a good path to an electric current because they have free to move electrons in their atoms

chapter 3

look at the computer so many electric wires are connected these wires are made of conductors which allow electricity to flow through it metals are good conductors as they contain loose electrons the most conductive metal is silver but it is expensive so copper is used instead which is cheaper and a good conductor

chapter 4

now lets see the benefits of using a good conductor good conductors have very low resistance so electric current can move easily if a high resistance conductor is selected then it will get hot when electric current flows through it this wastes electricity in heating the conductor that could have powered appliances using conductors with very low resistance saves electricity

chapter 5

the most useful and commonly used conductors for electric wires are following silver it's the best conductor but very expensive and it oxidizes easily copper home wiring is usually made of copper because it has a good amount of free electrons which can conduct electricity gold has low resistance but gold is very expensive it's used in cell phone circuits and computer chips aluminum this conductor is usually used in long electric transmission lines aluminum is lightweight but less conductive than copper

chapter 6

now lets learn about insulators an insulator is a material in which electric current does not flow freely through an electric circuit materials like glass and rubber have very good insulation property while others like water and wet wood have poor insulation property insulators are mostly used to insulate the conductors so if someone touches them they won't get electrocuted refrigerators need good insulators to insulate the electric wires and heat shield the appliances insulation performs a vital role in limiting heat gains in the system ensuring that the compressor load does not become excessive some examples of good insulators are porcelain rubber plastic paper wood and glass.