Question

Suggest an experiment to compare the conductivity of electricity by iron, copper, aluminium and zinc. Perform the experiment and prepare a short report on the results.

NCERT Class VIII
Science - Main Course Book

Chapter 4. Materials: Metals and Non-metals

Answer 1

Aim :
To compare the electrical conductivity of different metals.

Apparatus :
cell, torch bulb fitted in a holder,connecting wires,  different metal strips

Procedure:
1. Let us make a simple circuit by connecting one end of the torch to cell and other end end of torch to metal strip and  to cell back [as shown in the figure]
2.Let us insert a piece of Aluminium foil between the wires .And we will observe
3.Repeat the same activity with different metal strips like Iron, copper and zinc.

Observation:
1. In case of aluminium,iron,copper and zinc we observe that , bulb glows in the circuit.
2. This experiment proves that all metals are good conductors of electricity 
3. Copper wire is the best conductor among all the metals.

Conclusion:
This experiment proves that all metals are good conductors of electricity and
Copper wire is the best conductor among all the metals.

Answer 2

The thermal conductivity of this metal is, like electrical conductivity, determined largely by the free electrons. ... Both thermal and electrical conductivity depend in the same way on not just the mean free path, but also on other properties such as electron mass and even the number of free electrons per unit volume.

Thermal conductivity is looking at the transmission of molecular vibrations through a material which are measured as temperature. ... Electrical conductivity is measured by the ability of atoms or molecules to transfer electrons from one to the next.