Penicillin is a medicine that kills bacteria and helps with infections. Medicines like Penicillin are called antibiotics. Bacteria is responsible for some kinds of infections. Bacteria can enter body through cuts or through physical contact.

There was a scientist experimenting with growing bacteria in petridishes. He noticed that when there is mold, the mold killed bacteria. The chemical study of this mold yielded or gave Penicillin.

Before Penicillin and other antibiotics like Penicillin, people used to die sometimes just from simple cuts as the cuts get infected from bacteria.

antibiotics today save thousands of people every year.

Antibiotics are chemicals or medicine that cure infections by killing bacteria that cause those infections. Penicillin is an example of antibiotics.

Vitamins are chemicals in food that help the human body to be healthy and prevent some diseases.

Nylon is a man made replacement material for silk. Like silk it is smooth, light yet strong and durable. Carbon is an important element of Nylon. There are other man made materials like Nylon. Plastics are another example. These materials are called Polymers. Polymers have their molecular structure arranged into long connecting chains like a long train with attached trailers. This chaining gives them their strength.

Nylon is used for stockings, ropes, and nets.

Materials like Nylon and Plastic are called Polymers. Polymers have their molecular structure arranged into long connecting chains like a long train with attached trailers. This chaining gives them their strength.

The "Poly" in polymer stands for "many" implying the many connections that are there between its molecular or atomic structures.

Carbon is an important element of polymers.

Plastics are a kind of polymers. These are ligh weight and also strong and durable at the same time.

Petroleum is a kind of "oil" that is extracted from ground where it formed over millions of years from dead trees and other organic material.

When petroleum is refined and broken down we get Gasolene, Kerosene, and Diesel.

Petroleum is an essential fuel used in cars and other vehicles and also used to heat homes in winter.

Rubber is extracted from trees in nature. This rubber is further treated by heating it with "sulphur" to make it hard and durable. This process is called "vulcanization". Vulcanization is invented by a scientist named "Goodyear". This rubber is then used to make tires which are essential for transportation.

Liquids or solutions like lemon juice and vinegar are called acids.

Cleaning liquids like bleach and ammonia are called bases.

Liquids like water are considered neighther acids nor bases but neutral.

acids and bases react with each other chemically a lot and so one has to be very careful mixing them.

You can use and identification paper strip. When this strip is dipped in acid it will turn red. It will turn purple for a base.

1. Decomposition Chemical Reaction: A large molecule gets broken down into smaller molecules or atoms like water breaking down to become hydrogen and oxygen.

2. Combination Chemical Reaction: Smaller molecules join together to become a larger molecule like hydrogen and oxygen coming together to become water.

3. Replacement Chemical Reaction: Molecules instead of joining or decomposing simply get rearranged changing partners like in a dance.

Decomposition Chemical Reaction: A large molecule gets broken down into smaller molecules or atoms like water breaking down to become hydrogen and oxygen.

Replacement Chemical Reaction: Molecules instead of joining or decomposing simply get rearranged changing partners like in a dance.

Combination Chemical Reaction: Smaller molecules join together to become a larger molecule like hydrogen and oxygen coming together to become water.