Take pieces of metals like iron, aluminium, copper and zinc.
Place one of the metals on an iron block.
Strike it 4 to 5 times with a hammer.
Record the change in the shape of the metal.
Repeat the procedure with the other metals.
All metals will not break on striking with the hammer.
The force of the hammer changes the shape of the metal pieces, they become flat. On continuous hammering they can be flattened into sheets confirming that the metals are malleable.