Is Hair a Conductor of Electricity?

When considering whether hair is a conductor of electricity, it is important to understand the fundamental properties of hair and electricity. Generally, hair is considered a poor conductor of electricity, primarily due to its composition primarily made of keratin, a protein that does not allow electric current to flow easily. However, under certain conditions, such as when hair is wet, its conductivity improves due to the presence of water, a better conductor.

Why Hair is an Insulator

Under dry conditions, hair behaves more like an insulator than a conductor. This is because when charge is applied to an insulator, it stays in the same place, whereas in a conductor, the charge is distributed evenly across the surface. This is why a plastic comb gets charged when combed through dry hair, but a metal article does not. When hair is considered a conductor, it would act like metal by distributing the charge over its surface, leading to the charge being passed to the earth and dissipating. However, this does not occur with hair, supporting the notion that it is a poor conductor and an insulator.

Research and Applications

Research indicates that a single hair has a conductivity of 0.006 picosiemens, with a resistance of 200 teraohms (10^12 ohms) when the relative humidity of the air is 40%. This makes hair an excellent insulator under dry conditions. Interestingly, certain applications in the field of cryogenics have found that processed hair can be better than current insulation materials. Additionally, researchers have experimented with coating hair with gold to create ultra-thin conductors, demonstrating its potential beyond insulating properties.

Practical Implications

The behavior of hair in terms of static electricity is well-documented. We often experience static electricity through hair when combing it, especially during dry conditions. This is due to the build-up of electrical charges on hair, which then can attract small pieces of paper. Many cartoons and characters illustrate the effects of static electricity through hair standing apart after electric shocks, further emphasizing the insulating nature of hair.

Conclusion

In conclusion, hair is not a good conductor of electricity, making it an insulator under most conditions. The properties of hair and its interaction with electricity have been studied extensively, leading to various practical applications and experimental advancements. Whether through its natural composition or with modifications, hair plays a significant role in the realm of static electricity and insulation.