Answer:
- Fibreglass - Insulator
- piece of paper - Insulator
- copper - Conductor
- Stone - Insulator
- Aluminium - Conductor
- plastic spoon - Insulator
- Iron - Conductor
- Wood - Insulator
- Ruler - Conductor/Insulator
- Plastic straw - Insulator
- Glass - Insulator
- Brass - Conductor
- Gold - Conductor
- Cotton bud - Insulator
- Silver - Conductor
Step-by-step explanation:
Conductors are substances that can conduct electricity/heat. Usually, metals are good conductors as they have free electrons — electrons that are loosely held by the nucleus and are free to travel across the surface(they stay on the surface and are not free to escape into the surrounding space).
These free electrons help in the conduction of heat/electricity. Hence, substances containing these free particles are conductors.
Insulators do not allow heat/electricity to flow through them. Mostly, they are made up of molecules that are held together by strong intermolecular forces(eg: Plastic ).
[Note#9: Metal rulers are conductors whereas wooden rulers are insulators so, "ruler" comes under the category of both insulator as well as conductor].