Bad Hair Day?

Have you walked across a carpet and then felt a stinging sensation when you touched a door knob? What causes this tingling sensation? Have you combed your hair and still find them standing on end? What causes the hair to stand? The answer is static electricity.


What is static electricity?

All matter is made of atoms. An atom has three types of particles: (1) positively charged particles called protons (2) negatively charged particles called electrons and (3) particles with a neutral charge called neutrons.


Some materials such as nylon and hair lose electrons very easily. Have you combed your hair and realised that they are standing on end? When you run a dry comb through your hair, your hair loses some of its electrons to the comb. Hence your hair becomes positively charged while the comb becomes negatively charged. Your hair will stand on end as each strand of hair is positively charged and repel each other. Like charges repel each other, just like like poles repel each other in magnets.


The triboelectric series ranks materials by how easily they give up electrons. Hair and nylon are at the top of the series as they lose electrons easily. Scotch tape and Teflon are at the bottom as they grab electrons.

Watch a video on how a Van de Graaff Generator make hair stand

How does a Van de Graaff Generator work?

A Van de Graaff generator consists of a few parts: a motor, a belt, two rollers (the bottom roller can be made of nylon and the upper roller can be made of Teflon), two combs and a metal sphere. As the motor turns, the rubber belt first goes over the nylon roller. One comb pulls electrons from the nylon which loses electrons easily and transfers them to the rubber belt. The rubber belt then travels to the Teflon roller. The second comb collects the electrons from the belt and stores them on the metal sphere. Hence the sphere quickly collects a lot of electrons and becomes negatively charged.

When we touch the metal sphere while standing on an insulated material, the electrons will flow through our body and our hair. As we are standing on an insulated material, the charges cannot get to the ground. We are filled up with electrons. Even our hair is filled up with electrons and becomes negatively charged. Like charges repel. Hence the strands of hair which are negatively charged repel each other and stand.