What Does Composition Mean in Science: Understanding Elements

Understanding the fundamental elements of science is critical in comprehending various concepts that constitute the field. One of these essential concepts is ‘composition’ – the arrangement of elements that make up a compound. Composition refers to the physical and chemical properties of substances that are important in science.

The Definition of Composition in Science

Composition, in science, refers to the arrangement of elements that make up a substance. It defines the physical and chemical properties of a compound, which scientists and researchers use to distinguish one substance from another. The composition of a compound can be determined through different methods such as chemical analysis or spectroscopy.

The Importance of Composition in Science

The significance of composition in science is enormous. It is important in researching new drugs, chemical reactions, and materials science. For instance, the composition of a medicine affects its efficacy, safety and potential side effects, and its interaction with other drugs. Similarly, the composition of a polymer determines its physical and mechanical properties, critical in the design process of materials. In research, composition is used to evaluate the quality and purity of the sample being tested.

Basic Elements in Science

The basic elements of science are the building blocks of all matter. There are 118 known elements with unique atomic numbers and properties. They are classified into three main groups based on their physical properties and electron configuration: metals, nonmetals and metalloids. The elements present in a compound determine its physical and chemical properties.

The Classification of Chemical Compounds

Chemical compounds are substances made up of two or more elements that are chemically bound. These compounds are classified into different groups based on the types of chemical bonds that hold the atoms together. Compounds are either organic or inorganic, based on the presence or absence of carbon in their structure. Below are the different types of chemical compounds:

Organic Compounds

Organic compounds contain carbon atoms that are covalently bonded with hydrogen atoms. They include carbohydrates, proteins, lipids, and nucleic acids. These compounds are essential in biology and chemistry. They play crucial roles in bodily functions, provide energy and structural support, and act as enzymes or hormones.

Inorganic Compounds

Inorganic compounds do not contain carbon atoms but may contain other elements like nitrogen, sulfur, or phosphorus. These compounds do not typically have long chains of atoms like organic compounds, and they are mostly found in nature. Examples of inorganic compounds include water, carbon dioxide, and various acids and bases.

Metallic Compounds

Metallic compounds are elements with metallic properties that join to form a compound. Metals are considered ductile, malleable and good conductors of electricity and heat. Examples of metallic compounds include sodium chloride, copper sulphate and calcium carbonate.

Molecular Compounds

Molecular compounds are formed between two or more nonmetals based on their shared electrons. These compounds are usually gases or liquids with low melting and boiling points. Examples of molecular compounds include water, carbon dioxide and oxygen gas.

Composition and Chemical Properties of Water

Water is a universal solvent that forms the basis of life on earth. A water molecule comprises of two hydrogen atoms, and one oxygen atom covalently bonded. The shape of the water molecule is bent, with a tetrahedron shape, giving rise to the unique properties of water.

The Physical Properties of Water

The physical properties of water include its melting and boiling points, density, surface tension and viscosity. Water has a high boiling point of 100°C and melting point of 0°C. At room temperature, it is a liquid, making it an ideal solvent for many chemical reactions. Its density is 1 g/cm3 and varies with temperature.

The Chemical Properties of Water

The chemical properties of water refer to its ability to participate in chemical reactions. Water can dissociate into hydrogen ions (H+) and hydroxide ions (OH-) in aqueous medium. The pH of pure water is neutral, meaning that it has equal amounts of H+ and OH-. Water molecules can also form hydrogen bonds, resulting in its unique properties such as its high surface tension and adhesive properties.

The Composition and Properties of Air

Air is a mixture of gases that comprises the earth’s atmosphere. The composition of air is essential in understanding the different properties of air.

The Composition of Air

Air consists of approximately 78% nitrogen and 21% oxygen, with the remaining 1% comprising of rare gases such as argon and carbon dioxide. Water vapor and trace amounts of gases such as neon, helium, methane, ozone and hydrogen also exist within the atmosphere.

The Properties of Air

The properties of air depend on several factors such as temperature, humidity, pressure and altitude. Air has different properties such as density and viscosity, which varies with temperature and pressure.

The Properties and Composition of Rocks

Rocks are made up of different mineral compositions that affect the physical and chemical properties of the rocks. Understanding the composition and properties of rocks is critical in geology and other earth sciences.

The Composition of Rocks

Rocks are classified into three major groups based on their origin—igneous, sedimentary, and metamorphic rocks. They each have different mineral and chemical compositions, resulting in various properties like density, color, and texture.

The Properties of Rocks

The physical properties of rocks depend on their mineral composition and texture. These properties include hardness, fracture, texture, porosity, and permeability. The chemical properties of rocks describe the behavior of the minerals in the presence of other elements and compounds. Atomic structure and bonding affect a rock’s strength, durability, and resistance to weathering and erosion.


Composition is one of the fundamental concepts in science. Understanding the composition of compounds, elements, and substances is critical in designing new materials, discovering new drugs or chemicals, and evaluating sample quality and purity. Composition defines the physical, chemical, and mechanical properties of substances, which is essential in various sciences such as materials science, geology, and chemistry.

Most Common Questions and Answers on Composition in Science

  • What is composition in science?
    • Composition refers to the arrangement of elements that make up a substance in chemistry or materials science.
  • What are the basic elements in science?
    • The basic elements in science refer to the building blocks of matter.
  • What is the significance of composition in science?
    • The composition of a compound plays a vital role in various sciences where it provides insight into the physical, chemical, and mechanical properties of substances. Understanding the composition is important in designing new materials, discovering new drugs or chemicals, and evaluating sample quality and purity.


Brown, L. M. (2019). Fundamentals of geology. New York: Springer International Publishing.

Cheng, K., Clark, D. E., & Pollock, H. M. (2019). Materials science in engineering. London: Wiley-Blackwell.

Heaney, P. J. (2018). Chemistry and materials science. Hoboken, NJ: Wiley.

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