When we burn coal or wood in a burner or a stove, we see that the coal becomes extreme heat (burning lava) while burning. After some time we see that when the burner cools down, the coal finishes and the ash remains.

We use wood, cow dung cakes, kerosene (kerosene), bio gas or (LPG) gas in the stove for cooking. Scooters and buses run on diesel, petrol and (CNG) roads. In the fields, the tractor also runs on diesel.

Hydrocarbons are compounds of hydrogen and carbon. They are found in petroleum and natural gases. Methane (CH₄), Ethane (C₂H₆), propane (C₃H₈) and butane (C₄H₁₀) are some examples of hydrocarbons.

We often read the news in the newspapers that on seeing it in the morning it was found that some people were found dead in a closed room, who were sleeping by burning coal in the fireplace.

Carbon dioxide is 0.03 percent of the total volume of air. This gas is produced by burning of fuel, by respiration and by rotting of animals and plants (vegetables) and is added to the atmosphere.

Carbon is found in two forms - (1) crystalline (crystal-forming) and (2) amorphous (shapeless). Crystalline atoms are arranged in an order. Diamond and graphite are two forms of carbon.

Carbon is the 12th element found in abundant quantities in the Earth's upper layer (surface). In nature it is found in both independent and combined states.

Common salt is one of the common salts that is used mainly in our daily life. The chemical name of common salt is sodium chloride (NaCl). Another such salt is Soda, which is chemically named sodium bicarbonate (NaHCO₃).

In your daily life, you use different types of soaps and detergents. Washing and cleaning clothes are done with their help. These substances contain alkalis, which are chemically hydroxides or oxides of metals and react with water to form hydroxides.

You must have seen and eaten many such substances in your life, which have a sour taste. Some examples of these substances are lemon, tamarind, vinegar, orange and yogurt.

If some substances are mixed by mistake, then they need to be separated from each other, but sometimes it is very difficult to separate them. In such situations we use a variety of special methods, such as filtering, gleaning, sublimation, evaporation, precipitation to easily separate substances.

If you add some sugar or salt to the water, we see that in a short time they dissolve in the water and then do not appear in the water.

There are many substances that consist of the same type of atoms, such as oxygen, hydrogen, gold, copper, silver, iron, nitrogen, chlorine, sulfur, magnesium, aluminum. Such substances which consist of the same type of atoms are called elements.

Matter can be divided into three groups - solids, liquids and gases, depending on their states.

We see many things around us such as a table, chair, book, glass, hills, mountains, river, birds, animals, sun, moon and stars. All the objects seen around us are either born naturally or made by humans.

Whenever we feel hungry, we eat food. Food not only ends our hunger but also gives us energy. Food gives energy to do some essential elements required for the important works of the body.

Organs which tell us about the presence, element or taste of any objects are called sensory organs. We can see, listen or feel by these organs. We have five sensory organs - eyes, ears, nose, tongue and skin.

All the coordinating activities are done by our brain and nerves which is called nervous system.

Every cell of our body keeps on doing something or the other. Therefore, some garbage is always found there. These elements are harmful and should not be collected in body. It should be thrown out of the human body.

How digested food from food pipe and absorbed food from body reaches every cell? Carbon dioxide from all body parts and other waste elements related to waste materials (kidney, lungs)? All there works are done by a pump (heart) and artery coming out and reaching there.

All living organisms including humans breathe. Our body needs energy for many activities 24 hours a day. This energy is used inside the cells during breathing. It uses oxygen to disintegrate glucose from food.

 Every organism needs food to live. There are five steps of nutrition or food intake to its usage.

We are movable. We are not static at one place. We move from one place to another. We can also move our hands, legs, head and so on. All these movements are possible by the mixture of two systems in human body - bones and muscles. All bones together make skeleton system and all muscles together make muscle system.

Every organism whether plant or organisms reproduces his species and gives birth to new ones. Giving birth to a child of its own type is called reproduction. Plants reproduce in two ways - through seeds or by stem or leaves.