How does electrical energy work in a CD player? A CD player contains more than one electric circuit. The power supply provides the electrical...

1. It's simple! Dry air can provide static electricity! Walking on a carpet, in dry air, it's enough to cause static electricity.

 To prevent,  or even remove the static discharge, the air has to become more lconductive and this can happen by moistening the air. In this case, an humidifier works very well.

2. We know that the plane moves at high altitude(10.000 meters), where there are clouds. Study of the distribution of charges in the clouds showed that in general they are neutral on the whole, but are polarized. There are three types of polarized clouds : polar-positive clouds, polar -negative clouds and three-pole clouds. The first are the most prevalent, followed by the third type. So, you can imagine the amount of static electricity on the plane. When refuelling, the plane charged with electrostatic amount is in the presence of flammable gas, so, in order to avoid suddenly discharging of the static amount, the plane has to be connected to an electrical conductor which, at it's turn, is connected to the ground, in this way, the excess charge could be neutralized.