The striking blue walls in this photo are actually the sheer ice walls of a massive glacier. The glacier in the picture is on the coast of Antarctica, and the bluish water in the foreground is the ocean off the Antarctic coast. The photo represents an important concept in physical science. Can you guess what it is?
Water, Water Everywhere
The photo above represents water in three common states of matter. States of matter are different phases in which any given type of matter can exist. There are actually four well-known states of matter: solid, liquid, gas, and plasma. Plasma isn’t represented in the iceberg photo, but the other three states of matter are. The iceberg itself consists of water in the solid state, and the ocean consists of water in the liquid state.
Q: Where is water in the gaseous state in the above photo?
A: You can’t see the gaseous water, but it’s there. It exists as water vapor in the air.
Q: Water is one of the few substances that commonly exist on Earth in more than one state. Many other substances typically exist only in the solid, liquid, or gaseous state. Can you think of examples of matter that usually exists in just one of these three states?
A: Just look around you and you will see many examples of matter that usually exists in the solid state. They include soil, rock, wood, metal, glass, and plastic. Examples of matter that usually exist in the liquid state include cooking oil, gasoline, and mercury, which is the only metal that commonly exists as a liquid. Examples of matter that usually exists in the gaseous state include oxygen and nitrogen, which are the chief gases in Earth’s atmosphere.
Phases Are Physical
A given kind of matter has the same chemical makeup and the same chemical properties regardless of its state. That’s because state of matter is a physical property. As a result, when matter changes state, it doesn’t become a different kind of substance. For example, water is still water whether it exists as ice, liquid water, or water vapor.
The most common states of matter on Earth are solids, liquids, and gases. How do these states of matter differ? Their properties are contrasted in the Figure below. You can also watch videos about these three states of matter at the following URLs.
Properties of Matter in Different States
Q: The Figure below shows that a liquid takes the shape of its container. How could you demonstrate this?
A: You could put the same volume of liquid in containers with different shapes. This is illustrated below with a beaker (left) and a graduated cylinder (right). The shape of the liquid in the beaker is short and wide like the beaker, while the shape of the liquid in the graduated cylinder is tall and narrow like that container, but each container holds the same volume of liquid.
Q: How could you show that a gas spreads out to take the volume as well as the shape of its container?
A: You could pump air into a bicycle tire. The tire would become firm all over as air molecules spread out to take the shape of the tire and also to occupy the entire volume of the tire.
- States of matter are different phases in which any given type of matter can exist. There are four well-known states of matter—solid, liquid, gas, and plasma—but only the first three states are common on Earth.
- State of matter is a physical property of matter. A given kind of matter has the same chemical makeup and the same chemical properties, regardless of state.
- Solids have a fixed volume and a fixed shape. Liquids have a fixed volume but take the shape of their container. Gases take both the volume and the shape of their container.
Play the states of matter game at the following URL to reveal the hidden picture.