Answer the following question:
A group of students tested different materials to find out whether they could be drawn into thin wires. Their observations are given below.
| Material | Observation |
|---|---|
| Copper | Formed a wire of length 40 cm from the given sample |
| Aluminium | Formed a wire of length 60 cm from the given sample |
| Silver | Formed a wire of length 80 cm from the given sample |
| Gold | Formed a wire of length 120 cm from the given sample |
| Glass | Broke when stretched |
| Coal | Crumbled into pieces |
1. A student claims that "any material that can be stretched is ductile." Which additional observation would best verify this claim?
2. Which material is the most ductile according to the activity?
3. A student says, "Glass and coal are not suitable materials for making wires." Which observation from the activity best supports this conclusion?