What Is Chemistry? The Science of Matter and Change

Why does bread rise, why does iron rust and why does soap clean? Chemistry gives the answers. It is the science that studies what everything is made of, how it behaves and how it changes. This opening article gives you the big picture: what chemistry is, how chemists work, how they measure, and how to stay safe. The other Chemistry articles on EDUSAMBAM build on it.

1.What Is Chemistry?

Chemistry is the science that studies matter (anything that has mass and takes up space), its properties, its structure, and the changes it undergoes. Because everything physical around you is matter, from the air to your phone to your body, chemistry touches every part of life.

Chemistry is sometimes called the “central science” because it connects physics, biology, earth science and engineering. Physics explains the forces and energy inside atoms; biology depends on the chemical reactions inside cells; geology studies the minerals and chemistry of rocks; medicine relies on chemicals that act on the body.

2.Matter: Elements, Compounds and Mixtures

All matter can be sorted into a few types:

• An element contains only one kind of atom, for example oxygen, iron or gold. There are about 118 known elements, listed in the periodic table.
• A compound contains two or more elements chemically joined in a fixed ratio, for example water (H₂O) or sodium chloride (NaCl).
• A mixture contains two or more substances that are not chemically joined, for example air or sea water, and can be separated by physical methods.

A physical property can be observed without changing the substance, such as colour, melting point, density or whether it dissolves. A chemical property describes how a substance reacts, such as whether it burns or rusts. A physical change (like melting) does not make a new substance; a chemical change (like burning) does. You will study these ideas in the Mixtures and Solutions, States of Matter and Chemical Reactions articles.

3.The Main Branches of Chemistry

Chemistry is huge, so chemists specialise. Most areas belong to one of a few branches, though they often overlap.

4.A Short History of Chemistry

Chemistry grew from ancient crafts such as metalworking, pottery, dyeing and medicine. Some key steps are:

• Alchemy (many centuries, in several civilisations): alchemists tried to turn cheaper metals into gold and to find medicines that would prolong life. They did not succeed, but they developed apparatus and methods, such as distillation, that later chemists used.
• 1661, Robert Boyle: argued in his book The Sceptical Chymist that chemistry should rely on experiments and clear ideas about elements, and he studied how gases behave.
• 1770s to 1780s, Antoine Lavoisier: showed the role of oxygen in burning and established the conservation of mass through careful weighing.
• Early 1800s, John Dalton: developed the modern atomic theory.
• 1869, Dmitri Mendeleev: published a periodic table that organised the elements and predicted undiscovered ones.
• 1898 onward, Marie Curie and Pierre Curie: studied radioactivity and discovered polonium and radium. Marie Curie won Nobel Prizes in both Physics (1903) and Chemistry (1911).

Chemists in many countries have contributed to the science, including scholars of the medieval Islamic world such as Jabir ibn Hayyan, whose name is linked with early laboratory methods, though historians note that many works attributed to him were written by later authors.

5.How Chemists Work: The Scientific Method

Chemists learn about the world through experiments that test ideas. The process is a loop, not a fixed recipe.

A good experiment is a fair test: you change only one factor and keep everything else the same.

• The independent variable is the one thing you change on purpose.
• The dependent variable is what you measure as the result.
• Control variables are the things you keep the same.

Repeating an experiment improves reliability. Accuracy means how close a measurement is to the true value; precision means how close repeated measurements are to each other.

6.Measuring in Chemistry

Chemistry depends on careful measurement, using SI units (the international system).

Read liquid volumes at eye level, from the bottom of the curved surface (the meniscus). Write measurements with the correct unit, and avoid giving more digits than your apparatus can measure.

7.Staying Safe in the Laboratory

Safety is part of chemistry, not an extra. Hazard symbols on containers warn you of the risks.

• Wear eye protection, and tie back long hair. Wear a lab coat or apron if provided.
• Never taste, and do not sniff chemicals directly. If you need to smell a gas, waft it gently towards your nose, only when told to.
• Point test tubes away from people when heating, and use tongs or holders.
• Keep flammable liquids away from flames, and never leave a flame unattended.
• Do not eat or drink in the laboratory, and wash your hands afterwards.
• Report spills and breakages to your teacher at once; do not clean up chemicals yourself.
• If a chemical gets on your skin or in your eyes, rinse with plenty of running water and tell your teacher straight away.

8.Chemistry and Society

Chemistry has helped to produce medicines, clean water, fertilisers that help feed the world, fuels, plastics, fabrics and electronics. It also raises problems such as pollution, plastic waste and climate change. Green chemistry aims to design products and processes that use less energy, produce less waste and use safer materials. Understanding chemistry helps citizens make informed decisions about health, food, energy and the environment.

Careers that use chemistry include chemist, pharmacist, doctor, nurse, chemical engineer, food scientist, forensic scientist, environmental scientist, materials scientist, teacher and many more.

9.How to Study Chemistry Well

1. Learn the symbols and the first 20 elements early; they are the alphabet of chemistry.
2. Practise writing and balancing equations regularly, and check atoms on both sides.
3. Always write units with answers and show your working in steps.
4. Connect each topic to something real: cooking, cleaning, batteries, rust.
5. Draw diagrams and flow charts, and explain ideas aloud to someone else.
6. Use past papers and quizzes, and learn from every mistake.

Your chemistry roadmap on EDUSAMBAM

These articles take you through the subject in a logical order:

1. Atoms and the Periodic Table
2. Chemical Bonding
3. States of Matter and Changes of State
4. Mixtures and Solutions
5. Chemical Reactions and Equations
6. The Mole and Chemical Calculations
7. Acids, Bases and Salts
8. Chemistry of Metals and Non-Metals
9. Electrochemistry
10. Organic Chemistry Basics
11. Chemistry in Everyday Life

10.Common Mistakes to Avoid

• Thinking chemicals are only dangerous liquids in laboratories. Water, salt and sugar are chemicals, and natural substances can also be harmful.
• Calling every mixture a compound. Compounds have a fixed formula; mixtures do not.
• Mixing up physical and chemical changes. Check whether a new substance forms.
• Changing more than one variable in an experiment. The test is then not fair.
• Confusing accuracy and precision. A set of readings can be close together but all wrong.
• Ignoring units. A number without a unit has no meaning in chemistry.

11.Check Your Understanding

Try each question first, then tap it to reveal the answer.

12.Summary

13.Sources and Further Reading

These reputable sources were consulted to verify the facts in this article:

• Encyclopaedia Britannica: Overview of chemistry and its history. Chemistry.
• Royal Society of Chemistry: Teaching resources for school chemistry. rsc.org.
• American Chemical Society: Educational chemistry resources. acs.org.
• OpenStax: Free peer-reviewed textbook whose first chapter introduces chemistry and measurement. Chemistry 2e.
• LibreTexts Chemistry: Open educational chemistry library. chem.libretexts.org.

Copyright note: This article is original EDUSAMBAM educational writing. The diagrams are original inline SVG schematics created for this page and are not copied from any source. Links open external websites; the sources were used to check facts and are suggested for further study.

Last updated: 21 October 2026. Written for students up to age 18 and checked against standard school-level chemistry references. This is general education, not a substitute for your teacher, textbook or syllabus.