Tutorials

States of Matter

states of matter

Core Concept

In this tutorial, you will learn about the four main states of matter (solid, liquid, gas, and plasma), as well as some intermediate states of matter, by reading about properties, applications, and examples.

Topics Covered in Other Articles

Vocabulary

  • Magnetic field – a region around a magnet or an electric current that describes the magnetic influence on moving electric charges, currents, and magnetic materials. A moving electric charge in a magnetic field experiences a force perpendicular to its own velocity.
  • Matter– anything that has mass and occupies space; it constitutes atoms and compounds, which compose physical and chemical properties. (For more in depth information on the concept of matter, check out this article!)
  • Phase and Matter are occasionally used as synonyms; however, it is possible to form several phases that are in the same state of matter (such as how solids can have different crystalline structures)

What are the States of Matter?

There are four main states of matter that are observed in everyday life; these most common states of matter are: solid, liquid, gas, and plasma. Additionally, there are many intermediate states, many of which only exist under extreme conditions; in total, there are 20! Due to their difference of properties being their distinguishing factors, lets go over some of the states of matter below:

Solids

In the solid state, the particles are the most tightly packed together in a fixed arrangement. Due to the strong forces holding the particles together, only allowed to “move” in small vibrations; therefore, they stay in their fixed position. Solids contain the least amount of kinetic energy of all the states of matter because there is the least amount of movement. The particles of the compound are bound either in an organized, or geometric, lattice or a random unstructured shape. The materials present and conditions in which a solid is created dictates whether it will be a crystalline or amorphous solid. Usually when conditions are steady, such as slow and gradual cooling/heating, the particles have a chance to align uniformly; however, when there are extreme and rapid temperature changes, an indefinitely shaped solid will most likely be the result.

Solids have a definite shape and volume; they have a fixed position and will not conform to the shape of their container. Because they are so densely packed, solids tend to have a high density and are hard to compress further without use of great external force.

solid state of matter example

Classes of Solids

Whether or not we realize it, there are so many types of solids all around us; from table salt to a wooden chair! Because of the types of forces and the bonding between particles can vary, there are different classes of solids. These classes include metals, minerals, (glass) ceramics, organic molecules, composite materials, semiconductors, nano-materials and biomaterials. Due to their different force interactions, these categories of solids have different physical and chemical properties. Some of these properties could include elasticity, conductivity, light transmittance, plasticity, and more.

Liquids

In the liquid state, the particles have more freedom to flow around each other, as they are more loosely packed than a solid. Due to the weaker forces holding the particles together, they can flow each other and can conform to the shape of their container. However, the interaction is strong enough to keep the particles attracted to each other and as a result, liquids are incompressible; this means that as long as the temperature and pressure is constant, the liquid will have a fixed volume no matter the shape of its container. Since there is more movement than within a solid, liquids have a higher kinetic energy value.

Solids, when heated past their melting point, can absorb thermal energy, which gets the particles moving. Once they are moving enough (enough energy enters the system) to weaken the forces keeping them fixed, the particles will be allowed more movement as they transition into the liquid state. Some properties to look at when researching liquids can be buoyancy, surface tension, fluidity and density.

liquid state of matter example

Gases

In the gaseous state, the particles have even more freedom to move than in a liquid. Here, the particles can move in random directions without attracting each other. The molecules have enough kinetic energy that the intermolecular forces holding them together is negligible, which is the reasoning behind their amount of movement. Like liquids, gases do not have a definite shape, so it will conform to the shape of its container. However, unlike liquids, gases are compressible – they do not have a fixed volume; this means that the gas particles will spread out to fill the container they are in. Because of the distance the particles have from each other, it is common for a colorless gas to be invisible to the human eye; this is why we have ways to detect gases, such as carbon monoxide detectors!

Due to the properties of this state of matter, it can be hard to mathematically analyze gases. This is why there is the Ideal Gas Law, which sets up conditions for how a gas should act under ‘perfect’ conditions. There are also different mathematical relationships that set up conditions for the behavior of gases such as Boyle’s Law, Charles’ Law, Gay-Lussac’s Law, Henry’s Law, Combined Gas Law, and Avogadro’s Law.

gaseous state of matter example

Pure Gases vs Gas Mixture

A pure gas can come from the noble gases, such as neon and argon gas, from single elemental molecules, such as the diatomic gases like O2 and N2, or compound molecules, such as carbon dioxide. A gas mixture is a a more general word, such as air, used to describe an environment where different pure gases are found together.

Plasmas

This lesser known state of matter is a subset of gases. Similar to gases, plasmas do not have a definite shape or volume and have lower density. Again, this means that the particles will conform to both the shape and the volume of the container they are held within. However, while gases are made of molecules with a net charge of zero, plasmas are made of charged particles; they consist of a freely moving sea of electrons with positively charged nuclei “floating about”. The sea of electrons means that plasmas can conduct electrical charges and interact with other electromagnetic forces.

A plasma can become a gas by one of two ways. First, being exposed to a big (equal or greater than a charge difference of 2) voltage difference will strip the electrical charge and ionize it, giving it the neutral charge of a gas. Second, by exposing the plasma to high temperature conditions, the electrons leave the atoms, causing free electrons; since here, only some electrons are free, this is called partially ionized plasma. In some extreme conditions, it can be assumed that all electrons are free, which is called fully ionized plasma.

Examples of Plasmas

Plasma comprises approximately 99% of the universe; it glows in the form of stars, sun, nebulas, and auroras in the north and south poles. In addition, the branch of lightning in the sky and neon signs in the city streets are other examples of plasma.

Examples of Intermediate States of Matter

Bose-Einstein Condensates (BEC)

In 1995, scientists demonstrated a man-made state of matter, Bose-Einstein condensates. It is a group of atoms cooled to near absolute zero (-273.15°C). At this temperature, the atoms do not have free energy to move relative to each other. Therefore, they begin to coalesce into a single quantum state and become identical, behaving as a single atom. Bose-Einstein condensates plays a major role in the development of energy-efficient lasers and ultrafast optical switches. 

states of matter example

Color Glass Condensate

This type of matter has a theory to it! It supposedly exists inside atomic nuclei when they collide and travel close to the speed of light. in association with Einstein’s theory of relativity, a high energy nucleus can appear compressed and as a result, the gluons within the nucleus appears as a wall traveling at the speed of light. The gluon wall’s density can increase and the saturated gluon matter is known as the Color Glass Condensate. This state of matter is important because is used as the proposed universal form of matter to analyze and describe properties of high energy/interacting particles.

Further Reading

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