Define matter and list some examples.

Understanding the states of matter is crucial in grasping how matter interacts within our universe. At a fundamental level, matter can be classified into four main states: solid, liquid, gas, and plasma.

Solid is characterized by a fixed shape and volume. The particles are closely packed and only vibrate in place, providing the solid material with a definite form. For example, a rock or a chunk of metal are solids with their own distinct shapes.
Liquid has a definite volume but no specific shape, meaning it can flow to match the shape of its container. The particles in a liquid are less tightly packed than in a solid and have greater freedom to move. Water is the most common example of a liquid.
Gas has neither a fixed shape nor a fixed volume. Gas particles are spread out and move freely, expanding to fill the space they are in. Oxygen that we breathe and carbon dioxide exhaled by humans are common examples of gases.
Lastly, plasma is a less familiar state of matter that exists at very high temperatures. In plasma, electrons are removed from atoms, creating a soup of charged particles. The sun and stars are made of plasma.

Two fundamental properties of matter are mass and volume. Mass is a measure of the amount of substance in an object, usually measured in grams or kilograms. Volume, on the other hand, indicates the amount of space an object occupies and can be measured in liters or cubic meters.

Both properties are critical for characterizing different forms of matter. For instance, when you hold a rock, its mass is the measure of how much matter it contains, while its volume is how much space it takes up in your hand. In a classroom science experiment, students might measure the mass and volume of various objects using scales and graduated cylinders to comprehend these properties concretely. Understanding mass and volume is also essential for calculations in fields such as chemistry and physics where density (mass divided by volume) is a key concept.

Exploring examples of matter helps us recognize the diversity of materials that compose the world. From everyday items to less apparent examples, matter includes everything made of atoms and molecules.

Common examples of matter around us include water in all its forms, like ice (solid), liquid water, and water vapor (gas). The air we breathe, a mixture mainly of nitrogen and oxygen, is also matter in its gaseous state. Living organisms, from the tiniest bacteria to the largest whales, consist of matter as well, including their complex biological structures composed of various organic and inorganic substances.
Materials such as metals used in construction, plastics for manufacturing, and even the food we eat are all examples of matter. The diversity extends to many substances we cannot see, such as the natural gases underground or various chemicals used in laboratories. Understanding the myriad of forms that matter can take helps students appreciate the material composition of their surroundings and its relevance in science and everyday life.