Static Electricity : This is produced when two substances are rubbed together; the substances may be solids, liquids, or gases. Typical sources of static electricity are:
i) drive belts
ii) liquid/solid dispensers
iii) Van de Graff generators for deliberately producing static electricity
iv) plastic shoes, clothes and floors
The danger is not so much in the electric potential produced as in the sparks produced. Static electricity can be
1. prevented by preventing the friction
2. using earthed metal containers
3. wiping surfaces with dilute detergent solution
4. keeping the atmosphere damp