4.1.1 Malleability

What is Malleability?

It is the property by which materials can be beaten into thin sheets .

• Metals like copper and aluminium become flat when beaten .

• Gold and silver are the most malleable metals .

• Non-metals like coal and sulphur are brittle materials .

• Wood is neither malleable nor brittle .

Activity 4.1: Testing Malleability (Page 2)

What you need:

• Waste pieces of copper and aluminium
• An iron nail
• A piece of coal
• A pea-sized lump of sulphur (gandhak)
• A block of wood
• A hammer
• Hard surface

What to do:

• Step 1: Observe the appearances of all items
• Step 2: Note whether they are lustrous, hard or soft
• Step 3: Record observations in Table 4.1
• Step 4: Place each item on hard surface
• Step 5: Beat them with a hammer
• Step 6: Record what happens to each material

Question (Page 2): Are they lustrous?

Answer:
We have studied that metals have shiny surfaces called lustre . This is why:

• Copper , aluminium , and iron nail appear shiny
• Coal , sulphur , and wood appear dull

Question (Page 2): What do you think will happen?

Answer:
We have studied that malleable materials can be beaten flat . This is why:

• Metals will become slightly flattened
• Non-metals will break into pieces

Question (Page 2): Do the objects become slightly flattened or do they break into pieces?

Answer:
We have studied that malleability determines behavior under hammering . This is why:

• Copper , aluminium , iron become slightly flattened
• Coal and sulphur break into pieces
• Wood shows neither behavior

Observations

What you see:

Why this happens:
We have studied that malleability is a property of metals . This is why metals flatten while non-metals break .

• Metal atoms can slide over each other
• Non-metal structures are rigid and brittle

Question (Page 2): Are all metals hard and solid?

Answer:
No, they are not all hard and solid.

• Sodium and potassium are soft metals
• Mercury is liquid at room temperature