Matter
ICSE Class 6 · Physics · Chapter 1
What this chapter covers
- Matter and its composition
- States of matter
- Characteristics of the three states
- Distinguishing properties of solids, liquids and gases
- Classifying objects by state
Key definitions
Matter is anything that has mass and takes up space.
Atoms are the tiny particles that all matter is built from.
A molecule is a group of two or more atoms joined together.
The states of matter are the three forms in which matter is found: solid, liquid and gas.
A solid is a form of matter that has a fixed shape and a fixed volume.
A liquid is a form of matter that has a fixed volume but no fixed shape.
A gas is a form of matter that has neither a fixed shape nor a fixed volume.
Texture is the way the surface of a thing feels when you touch it.
Volume is the amount of space that a thing takes up.
Key points
- Matter is anything that has mass and takes up space.
- All matter is made of tiny particles called atoms and molecules, which are too small to be seen.
- A molecule is a group of two or more atoms joined together.
- Matter is found in three states: solid, liquid and gas.
- A solid has a fixed shape and a fixed volume.
- A liquid has a fixed volume but takes the shape of its container.
- A gas has no fixed shape and no fixed volume; it fills the whole container.
- Solids have textures you can feel; liquids feel wet; gases are felt only when they move.
- Liquids and gases flow; solids do not.
- Gases can easily be pressed into a smaller space; solids and liquids cannot.
- Powders such as sugar and sand are solids, because each grain keeps its own shape.
- To classify an object, check whether it keeps its own shape and its own volume.
Questions answered
What is matter? Give two examples of matter that you can see and one that you cannot see.
Matter is anything that has mass and takes up space. A book and a glass of milk are matter you can see. Air is matter you cannot see.
Name two things that are not matter.
Light and sound are not matter. Neither of them has mass or takes up space.
What are the tiny particles that make up all matter?
All matter is made of tiny particles called atoms and molecules. They are too small to be seen with the eye.
Which state of matter has a fixed volume but no fixed shape? Give one example.
A liquid has a fixed volume but no fixed shape. Water is an example.
Why is a gas said to have no fixed volume?
A gas spreads out to fill the whole of any container it is put in. The same amount of gas can fill a small bottle or a large room, so its volume is not fixed.
Salt can be poured into a jar like water. Is salt a liquid? Give a reason.
No, salt is a solid. Each grain of salt has its own fixed shape and does not change shape when it is poured.
Sort these into solids, liquids and gases: a marble, mustard oil, steam, a pencil, air in a tyre, lemon juice.
Solids are a marble and a pencil. Liquids are mustard oil and lemon juice. Gases are steam and the air in a tyre.
Describe the texture of a solid, a liquid and a gas.
A solid can be rough, smooth, hard or soft to touch. A liquid feels wet and may be thick or thin. A gas cannot be felt unless it is moving, like a breeze.