Detailed description of physical changes and its examples

1. Grade: 7
Subject: SCIENCE
CH – 6 Physical and Chemical changes

2. RECAP
• Reversible Changes – a change which can be
reversed to form the original substance is
called a reversible change.
• Irreversible Change – a change which cannot
be reversed.

3. PHYSICAL PROPERTIES OF SUBSTANCES
• Shape – Folding and Cutting
the paper changes the shape
of paper. But the property of
paper is intact.
• Size - with continuous usage
a chalk reduces in size. But if
the chalk dust is collected
and water is added and
rolled, we can again get the
chalk.
• Colour – when a piece of
Iron is heated, it becomes
red hot, but on cooling
regains the original colour.
• State of a substance – water
can exist in three states –
solid, liquid and gas.

5. PHYSICAL CHANGES
• Any change in the physical properties of
substances (Shape, Size, Colour or State) is
called a physical change.
• Most Physical Changes are Reversible. Not all
of them. For eg.
Folding of Paper – Reversible Physical Change
Cutting of paper – Irreversible Physical Change
• NO NEW SUBSTANCE IS FORMED.