Grade 6 → Matter and its states ↓
States of matter
Matter is anything that occupies space and has mass. Everything around us is made of matter, from the air we breathe to the food we eat. Matter exists in different forms, often called "states." In this longer lesson, we'll explore the different states of matter and what makes each state unique.
What is the matter?
Matter is made up of tiny particles called atoms and molecules. These particles are so small that we cannot see them without a powerful microscope. Matter can combine and rearrange in countless ways, forming everything in the universe.
General properties of matter
Here are some basic properties that apply to all substances:
- Volume: The space occupied by an object.
- Mass: The amount of matter in an object.
- Density: This is a measure of how much mass is contained in a given volume.
Three main states of matter
Matter is usually found in three states: solid, liquid, and gas. Each state has different properties and can change from one state to another under certain conditions. Let's look at each state more closely.
Solids
The characteristic of solids is that they have a definite shape and volume. The atoms or molecules in a solid are adjacent to each other in a definite arrangement, due to which solids become rigid and maintain their shape.
Liquids
Liquids have a definite volume, but they do not have a definite shape. This means that the liquid will take the shape of its container. The atoms or molecules in liquids are more loosely packed than those in solids, allowing them to move more freely even while still being in contact with each other.
Gases
Gases have neither a definite shape nor a volume. They expand to fill the entire space of their container. The atoms or molecules in a gas are much more spread out than those in solids and liquids, allowing them to move freely and rapidly.
Changing states of matter
Matter can change from one state to another when energy, usually in the form of heat, is added or removed. Here are some of the processes through which states of matter change:
Melting
Melting is the process of changing from a solid to a liquid. When we heat a solid, its atoms or molecules gain energy and pass past each other more freely, turning it into a liquid.
H 2 O (solid) + heat → H 2 O (liquid)
Solidify
Freezing is the change from a liquid to a solid. It occurs when we remove heat from a liquid, causing its particles to lose energy and bond more tightly, forming a solid.
H 2 O (liquid) → H 2 O (solid) + heat loss
Evaporation
Evaporation is the conversion of a liquid into a gas, which occurs at the surface of the liquid. It occurs when particles in the liquid gain enough energy that they break free from the liquid and become gas particles.
H 2 O (liquid) + heat → H 2 O (gas)
Condensation
Condensation is the change from a gas to a liquid. It occurs when gas particles lose energy and come closer to each other to form a liquid.
H 2 O (gas) → H 2 O (liquid) + heat loss
Sublimation and deposition
Sublimation is the process in which a solid substance changes directly into a gas, bypassing the liquid state. Deposition is the opposite process in which a gas changes directly into a solid.
CO 2 (solid) → CO 2 (gas)
(sublimation)H 2 O (gas) → H 2 O (solid)
(deposition)
Unusual states of matter
In addition to the three main states, there are also some less common states that matter can take under special circumstances. These include plasma and Bose-Einstein condensates.
Plasma
Plasma is often called the fourth state of matter. Plasma is gases heated to very high temperatures, causing the atoms to lose their electrons. Plasmas are found in stars, including our Sun.
Gas + intense heat → Plasma + free electrons
Bose–Einstein condensates
A Bose-Einstein condensate (BEC) is a state of matter that occurs at temperatures close to absolute zero. At such low temperatures, a group of atoms cool down and behave as if they were a single particle.
Understanding matter and everyday life
States of matter are part of our everyday experiences. Knowing how and why states of matter change can help us understand natural processes and even design technologies that make our lives easier.
Conclusion
Matter is all around us, and understanding its various states enhances our understanding of science and the world. Solids, liquids, gases, and even plasma and Bose-Einstein condensates each have unique properties and behaviors. By learning about the states of matter, we are able to better understand the complex fabric of science we encounter in our daily lives.