States of Matter Class 3 Notes Science

States of Matter

• Everything we see around us, like tables, chairs, water, and air, takes up space and has weight. These things are called matter. Matter is everywhere. 
• Scientists say that matter can be solid like a table, liquid like water, or a gas like air. 
• Matter is made of tiny parts called molecules, and these molecules are put together in different ways in different things.

Three State of Matter

1. Solids

• Solid is a state of matter that has a definite shape and volume. 
• In solids, molecules are closely packed. That is why solids are hard. 
• Solids do not change their shape when moved from one container to another container, i.e., they have a definite shape and a definite volume. 
• For example, chair, dice, cup, book, wood, etc.

2. Liquid

• Liquid is a state of matter that does not have a definite shape and flows easily. 
• The molecules that make up a liquid are loosely packed than those in solids and are able to move freely. 
• Liquids take the shape of the container in which they are kept and have a fixed volume. 
• For example, water, oil, milk, juice, etc.

Gases

• Like liquids, gases also do not have a definite shape.
• The molecules that make up gases are more loosely packed than liquids.
• They are able to move randomly. 
• Like liquids, gases take the shape of the container they are kept in.
• They do not have a fixed volume. 
• Air is a mixture of many gases. 
• Examples of gases are oxygen, carbon dioxide, hydrogen, nitrogen, etc.

Change of States

• States of matter can be changed from one form to another. 
• A solid can change into a liquid on heating. 
• On heating, a liquid becomes a gas. 
• On cooling down, a gas  becomes a liquid. 
• When we freeze a liquid, it becomes  solid. 
• For example, on heating, ice changes into water (liquid), which on further heating, changes into vapours.

Conclusion

Matter around us can exist in three different states: solid, liquid, and gas. Each state has unique properties based on how its molecules are arranged and move. Changes in temperature can cause matter to switch from one state to another, like ice melting into water or water evaporating into vapor. Understanding these states and changes helps us see how things around us work and interact in everyday life.