1.0 Introduction to Matter
Look around you. Your book, pencil, chair, water bottle, school bag, food, air inside a balloon and even your own body are made of matter. In Physics, we study matter because almost everything around us is made of it. Matter is the basic material of the universe.
The easiest way to identify matter is to ask two questions: Does it have mass? and Does it occupy space? If the answer to both questions is yes, it is matter.
Statement: Matter is anything that has mass and occupies space.
Mass means the amount of matter present in an object. A stone has more mass than a feather because it contains more matter. Space occupied by matter is called volume. A football occupies more space than a tennis ball, so it has a greater volume.
Why is air considered matter even though we cannot see it? Air has mass and occupies space. When we fill a balloon with air, the balloon becomes bigger. This shows that air occupies space. If we compare an empty football and a football filled with air, the filled one has slightly more mass. This proves that air is matter.
When you blow air into a balloon, you are adding matter into it. When you pour water into a glass, water takes the shape of the glass because it occupies space. When you pack books into a bag, the bag becomes heavier because more matter has been added.
Some things are not matter. Light, sound, heat and shadow are not matter. They do not have mass and do not occupy space like objects, liquids or gases. Light and heat are forms of energy. Sound is produced by vibrations. A shadow is only a dark region formed when light is blocked.
Do not write that everything around us is matter. Light, heat, sound and shadow are around us, but they are not matter because they do not have mass and do not occupy space.
| Example | Matter or Not Matter? | Reason |
|---|---|---|
| Book | Matter | It has mass and occupies space. |
| Water | Matter | It has mass and takes space in a container. |
| Air | Matter | It has mass and fills space. |
| Light | Not Matter | It is energy, not a material object. |
| Shadow | Not Matter | It is formed when light is blocked. |
MOS helps you remember matter: Mass + Occupies Space = Matter.
- Matter is anything that has mass and occupies space.
- Solids, liquids and gases are matter.
- Light, sound, heat and shadow are not matter.
A balloon becomes bigger when air is filled into it. What does this tell us about air?
2.0 Properties of Matter
Matter can be identified by its properties. The two most important properties of matter are mass and volume. If something has mass and occupies volume, it is matter. These properties help us compare objects in daily life.
Statement: Mass is the amount of matter present in an object. Volume is the space occupied by an object.
Mass tells us how much matter is present. A school bag with many books has more mass than an empty bag. A watermelon has more mass than a lemon. Mass is commonly measured in gram (g) and kilogram (kg).
Volume tells us how much space matter occupies. A large bottle has more volume than a small cup. A football occupies more space than a cricket ball. Volume of liquids is commonly measured in millilitre (mL) and litre (L).
Volume = length x breadth x height
- Length: Longer side of the object (cm or m)
- Breadth: Width of the object (cm or m)
- Height: Vertical size of the object (cm or m)
- Volume: Space occupied (cm³ or m³)
Q: A small box has length 5 cm, breadth 3 cm and height 2 cm. Find its volume.
Solution: Volume = length x breadth x height
Volume = 5 x 3 x 2 = 30 cm³
Answer: The volume of the box is 30 cm³.
💡 Unit Conversion Tip: If all measurements are in cm, volume will be in cm³. If measurements are in m, volume will be in m³.
When you buy fruits, the shopkeeper measures their mass using a weighing balance. When you buy milk or water, it is measured by volume in litres or millilitres. Physics helps us measure matter accurately in daily life.
Another term students often hear is weight. Weight is related to the pull of gravity on an object. At Class 6 level, remember this simple difference: mass tells how much matter is present, while weight tells how strongly gravity pulls that matter.
Mass and weight are not exactly the same. Mass is the amount of matter in an object. Weight is the force with which Earth pulls the object. In Class 6 exams, write this difference clearly.
| Property | Meaning | Common Unit | Measuring Instrument |
|---|---|---|---|
| Mass | Amount of matter | g, kg | Beam balance or electronic balance |
| Volume | Space occupied | mL, L, cm³ | Measuring cylinder or measuring jar |
| Weight | Pull of gravity on matter | newton (N) | Spring balance |
MV helps you remember the two main properties of matter: Mass and Volume.
- Mass is the amount of matter in an object.
- Volume is the space occupied by matter.
- Mass and weight are related but not exactly the same.
If two bottles have the same volume, will they always have the same mass? Why or why not?
3.0 States of Matter
Matter mainly exists in three common states: solid, liquid and gas. These states are different because their particles are arranged differently and move differently. A stone is a solid, water is a liquid and air is a gas.
Statement: The physical forms in which matter exists are called states of matter. The three common states are solid, liquid and gas.
A solid has a fixed shape and fixed volume. A liquid has a fixed volume but no fixed shape. It takes the shape of the container. A gas has no fixed shape and no fixed volume. It spreads to fill the entire space available.
Why do solids keep their shape? In solids, particles are closely packed and cannot move freely. They only vibrate in their fixed positions. In liquids, particles are close but can slide over one another. In gases, particles are far apart and move freely in all directions.
| State | Shape | Volume | Particle Arrangement | Examples |
|---|---|---|---|---|
| Solid | Fixed shape | Fixed volume | Particles are tightly packed | Stone, book, ice |
| Liquid | No fixed shape | Fixed volume | Particles are close but can slide | Water, milk, oil |
| Gas | No fixed shape | No fixed volume | Particles are far apart and move freely | Air, steam, oxygen |
A lunch box keeps its shape because it is solid. Water takes the shape of a glass because it is liquid. Perfume smell spreads across a room because perfume vapour mixes with air like a gas. These examples show states of matter in daily life.
Do not write that liquids have no volume. Liquids have fixed volume, but they do not have fixed shape. They take the shape of the container.
S-L-G helps you remember the three states: Solid has fixed shape, Liquid flows, Gas spreads.
The same substance can exist in different states. Water can exist as ice in solid state, liquid water in liquid state and steam or water vapour in gaseous state. The substance is the same, but its state changes due to heating or cooling.
Gas particles are always moving very fast. This is why gases spread quickly and fill empty spaces. When you open a perfume bottle, its smell spreads because gas particles move and mix with air.
- Matter commonly exists as solid, liquid and gas.
- Solids have fixed shape and fixed volume.
- Liquids have fixed volume, while gases have neither fixed shape nor fixed volume.
Why does a gas fill the whole container, but a solid does not?
4.0 Change of State of Matter
Matter can change from one state to another when it is heated or cooled. Ice can change into water, water can change into steam, and steam can change back into water. These changes are called changes of state.
Statement: The process in which matter changes from one physical state to another due to heating or cooling is called change of state.
The important changes of state are melting, freezing, evaporation, boiling and condensation. These changes do not usually form a new substance. For example, ice, water and steam are all forms of the same substance: water.
Why does heating change the state of matter? When we heat a substance, its particles get more energy and move faster. In ice, particles are fixed in position. When ice is heated, particles gain energy and move more freely, so ice melts into water. On further heating, water particles gain even more energy and change into water vapour.
| Process | Change | Example |
|---|---|---|
| Melting | Solid → Liquid | Ice changes into water |
| Freezing | Liquid → Solid | Water changes into ice |
| Evaporation | Liquid → Gas | Wet clothes dry in sunlight |
| Condensation | Gas → Liquid | Water droplets form on a cold glass |
Wet clothes dry faster in sunlight because water in the clothes gets heat from the Sun. Water particles gain energy and escape into the air as water vapour. This is evaporation. Wind also helps by carrying away water vapour from the clothes.
Evaporation and boiling are not exactly the same. Evaporation can happen slowly from the surface of a liquid at many temperatures. Boiling happens rapidly throughout the liquid at its boiling point.
| Point | Evaporation | Boiling |
|---|---|---|
| Speed | Slow process | Fast process |
| Where It Happens | Only at the surface | Throughout the liquid |
| Example | Drying clothes | Water boiling in a kettle |
Heat moves matter forward: Solid → Liquid → Gas. Cooling brings it back: Gas → Liquid → Solid.
The water cycle in nature depends on changes of state. Water evaporates from oceans and rivers, condenses to form clouds and returns to Earth as rain.
- Matter changes state when it is heated or cooled.
- Melting, freezing, evaporation and condensation are changes of state.
- Evaporation and boiling are different processes.
Why do wet clothes dry faster on a hot and windy day?
5.0 Revision, Applications and Exam Readiness
Matter is the material from which objects around us are made. Everything that has mass and occupies space is matter. In this chapter, we learned that matter can be solid, liquid or gas, and it can change from one state to another by heating or cooling.
Matter is used everywhere in daily life. Solids like wood, iron and plastic are used to make furniture, vehicles and tools. Liquids like water, milk and petrol are used for drinking, cooking, cleaning and transport. Gases like air, oxygen and LPG are used for breathing, burning and cooking.
How can the same substance exist as solid, liquid and gas? The substance remains the same, but the arrangement and movement of its particles change. Water can exist as ice, liquid water and water vapour. Heating makes particles move faster, while cooling makes them move slower.
Do not confuse change of state with change of substance. When ice melts into water, no new substance is formed. It is only a physical change of state.
| Topic | Quick Revision Point | Example |
|---|---|---|
| Matter | Anything that has mass and occupies space | Book, water, air |
| Mass | Amount of matter in an object | Mass of fruits in kg |
| Volume | Space occupied by matter | Water in a bottle |
| Solid | Fixed shape and fixed volume | Stone, book, ice |
| Liquid | Fixed volume but no fixed shape | Water, milk, oil |
| Gas | No fixed shape and no fixed volume | Air, steam, oxygen |
| Change of State | Matter changes state due to heating or cooling | Ice melting into water |
Volume of cuboid = length x breadth x height
- Length: Long side of object (cm or m)
- Breadth: Width of object (cm or m)
- Height: Vertical size of object (cm or m)
- Volume: Space occupied by object (cm³ or m³)
Matter Check = M + S
M = Has Mass
S = Occupies Space
If both are present, it is matter.
- Define matter.
- Give two examples of things that are matter and two examples of things that are not matter.
- Write one difference between solid, liquid and gas.
- Why does a gas fill the whole container?
- What is the difference between evaporation and boiling?
- Matter has mass and occupies space.
- Matter exists mainly as solid, liquid and gas.
- Heating and cooling can change the state of matter.
How can the same substance, water, exist as ice, liquid water and steam?