Matter is the material substance of which all physical objects are composed. It has mass and occupies space. All matter is made up of atoms, which are the smallest units of matter.
Atoms are indivisible and indestructible; they cannot be created or destroyed. The structure of an atom is a central nucleus composed of protons and neutrons, with electrons orbiting around this nucleus.
The properties of matter depend on the way its atoms are arranged. For example, water (H2O) consists of two hydrogen atoms bonded to one oxygen atom. The different arrangements of atoms give rise to different types of molecules, which in turn make up the different phases of matter: solids, liquids and gases.
The study of matter is known as physics. Physics investigates the fundamental nature ofmatter and its interactions with energy. In doing so, it makes use of a variety mathematical models and laws, such as Newton’s laws offorcesand motionand Einstein’s theoryof relativity.