Charge up a light bulb When you rub the comb through your hair, the friction between your hair and the comb actually causes electrons to travel from your hair to the comb. Your body (hair) becomes positively charged (because it has more protons than electrons) while the comb becomes negatively charged (it gained electrons from your hair) . The comb, in effect, becomes charged. When you touch the comb to the end of the light bulb, the charged comb discharges into the light bulb causing the bulb to emit small pulses of light.