Glass rod is rubbed with silk
Answers
ELECTROSTATICS
When a glass rod is rubbed with silk, glass happens to lose electrons easily and silk grabs them away from the glass atoms. So after rubbing, the glass becomes positively charged and the silk becomes negatively charged. Thus equal but opposite charge are produced on the both, and they stick together. This is because like charges repel and unlike charges attract.
When the glass rod is rubbed with silk, the silk strips electrons from the rod, leaving it a positive charge. When the hard rubber rod is rubbed with wool, it gains electrons from the wool, gaining a negative charge.
This is actually one of the most fail-safe electrostatics experiments I have ever seen. The photos included on this page were taken on a hot, humid day (which usually spells death for electrostatic experiments). If your results seem rather weak and unimpressive, rub the rods more vigorously and for more time and it should work.
hope its helpful