An element is a substance that cannot be broken down into simpler substances by chemical means. Elements are divided into […]

Acids Acids occur naturally in substances like unripe mangoes and oranges, giving them a sour taste. They have a sour […]

Key Terms Solution: a homogeneous (uniform) mixture of a solute and a solvent. Solvent: the majority component of a solution, […]

Hand picking: removing one component of a mixture by hand, e.g. picking stones out of rice. Sieving: separates solid particles […]

Water is often called the universal solvent because it can dissolve so many other substances. Hard and Soft Water Hard […]

Air is a mixture of gases: roughly 78% nitrogen, 21% oxygen, 0.03–0.04% carbon dioxide, plus variable amounts of water vapour, […]

What Is Matter? Matter is anything that has mass and occupies space — stones, trees, chairs, dust and chalk are […]

Matter can be divided into living matter (which meets all the characteristics of life — plants and animals, studied in […]

The Laboratory A laboratory is a special room where scientists carry out experiments and research, and where chemicals and equipment […]

Science and Its Branches Science is the systematic, orderly study of nature — the world around us — and a […]