Here's a breakdown:
* Solids: Most metals (like iron, gold, silver), rocks, wood, and ice are solid at room temperature. They have a fixed shape and volume.
* Liquids: Water, oil, alcohol, and mercury are liquid at room temperature. They take the shape of their container but have a fixed volume.
* Gases: Air, oxygen, nitrogen, and carbon dioxide are gases at room temperature. They take the shape and volume of their container.
Note: "Room temperature" is generally considered to be around 20-25°C (68-77°F).
