Why do synthetic fabrics create more static electricity than natural fibers? Also, if static is usually stronger when the air is dry, why is there lightning mostly in the summer when it is humid?
Synthetic fabrics are made of chemicals consisting of long-stranded molecules mixed together and then woven into the fabrics used to make clothing, carpeting, and other common materials. The long molecules consisting of many atoms are held together at the molecular level by electron bonds ranging in bonding power from strong to weak. Some of those atoms share their electrons tightly with their neighboring atoms and therefore make a tight, long-lasting fabric.
Some atoms, although being bonded strongly to the molecular group have a weak electron or two that is barley held in its orbit around its atom. It is these loosely-held electrons that are rubbed off, stick to other materials, and form static electricity. That static electricity is actually stored electricity poised to spark when the carrier material is placed near a grounded object. That grounded object is ready to accept the electrons from the material that picked them up from the synthetic fiber — which did not need them for its stability.
Static electricity builds up and appears stronger in dry weather because there is little moisture to cause it to leak off any temporary holding material.
There is more lightening during high humidity seasons than during dry seasons because the forces of nature all come together and their net effect is the overt and observed effect. Can you name the relevant interacting factors here? Humidity, temperatures, dust, movements and speeds, masses, and more?
In the case of lightening during the summer, conditions are good for the formation of large clouds. These clouds move fast and rub against each other. That high-speed rubbing scrapes and shuffles huge amounts of electrons that collect on some cloud formations in specific air masses — even in damp or wet air masses. The build up of electrons from so much rubbing is large. Once the amount of electrons reaches a voltage (potential current) that is enough to overcome the resistance of the air, a spark jumps from the clouds to the positively-charged earth. Summer air is moist so that also contributes to decreasing the air’s resistance.
That grounding of the clouds is similar to rubbing your socks on a synthetic carpet and then touching a grounded object which causes a spark between you and the grounded object.