Question

We know that rubber is a bad conductor of electricity. We are advised to wear rubber slippers while working on electronics. But in winter if we touch others they get a shock even if we are wearing rubber shoes. Why is it so?

Answer 1

Static electricity is around us all the time, but in normal humidity conditions, that charge flows from place to place gradually, it can even travel through air, if the air is not too dry, so it never builds up to any sizeable shock.
In cold weather, the relative humidity is often quite low, and when we heat the air in buildings, the humidity in that air gets even lower, (relative humidity is the percentage of water that air is able to absorb at a given temperature. The warmer it is, the more water it can carry, and so the same amount of water would be a lower relative humidity at a higher temperature. If air at 100% humidity were warmed until it could carry twice the amount of water, it would then be at 50% humidity with the same amount of water vapor - So because the air is dry, we are insulated from this slow level discharge. the charge keeps building up because it cannot travel across dry air easily, and 'waits' until the voltage is higher and is able to 'arc' to another object that has built up less charge like the ground, or something electrically connected to it. It easily builds up to thousands of volts And you get zapped. Water vapor in the air is a conductor. It helps dissipate build up of static electricity continually. If cold weather, lower air temps mean less water vapor and less dissipation of static. So static builds up until you get close enough to a ground and zap, your dissipated. It's much more comfortable being continually dissipated than instantaneously dissipated. Things that help: humidifiers, fabric softeners, lotions. In the car, rub a fabric softener sheet on your cloth seat then throw it under the seat. It helps keep static from being generated when your synthetic clothing rubs across your synthetic seats and will keep your car smelling fresh.