Pull it into a wire
Metals can be drawn into long thin wires.
Wires everywhere
Look around: the wires in electrical fittings, the strings of a sitar, veena or guitar, even bangles and necklaces are made of thin metal wires.
A lump of copper and a lump of coal are pulled through a small hole. What do you think happens?
What this lesson covers
The idea
Ductility is the property by which materials can be drawn into wires; it is mainly possessed by metals, gold being extremely ductile, while coal and sulfur are not ductile.
Wires everywhere
Look around: the wires in electrical fittings, the strings of a sitar, veena or guitar, even bangles and necklaces are made of thin metal wires.
A lump of copper and a lump of coal are pulled through a small hole. What do you think happens?
- Copper becomes a wire; coal crumbles
- Both become wires
- Neither becomes a wire
Draw a wire
Pull each lump through the hole in the plate. First guess, then watch.
Ductile
Ductility is the property by which materials can be drawn into wires. It is mainly possessed by metals. Gold is extremely ductile: 1 gram can be drawn into a wire 2 kilometres long. Coal and sulfur are not ductile.
Dive deeper: ropes of steel wires (steel is iron mixed with carbon) can carry heavy loads. They are used in suspension bridges and in cranes.
- Material | Pulled through the hole | So it is
- Gold, copper, aluminium | becomes a wire | ductile
- Coal, sulfur | crumbles | not ductile
Notes
Ductility: materials can be drawn into wires. Mainly metals. 1 gram of gold can make a 2 km wire. Coal and sulfur are not ductile.
Check yourself
The property by which materials can be drawn into wires is called...
1 gram of gold can be drawn into a wire how many kilometres long?
Answer: 2 km
1 gram of gold can be drawn into a wire 2 kilometres long.
Which of these uses the ductility of metals?
Which of these cannot be drawn into wires?
- malleability. Malleability is being beaten into thin sheets.
- sonority. Sonority is the ringing sound of metals.
- ductility — correct. Yes! Ductile materials can be drawn into wires.
- Silver foil on sweets. That uses malleability: beating into thin sheets.
- The copper wires in electrical fittings — correct. Yes! Copper is drawn into wires.
- The ringing of a coin. That is sonority.
- Coal — correct. Yes! Coal is not ductile. It crumbles.
- Copper. Copper is ductile.
- Aluminium. Aluminium is ductile.