P4A Sparks

When one insulating material is rubbed with another electrically charged material it can become electrically charged. Why is this?

How can you discharge electricity and how does this process work?

What is one problem with static electricity?

Two insulating materials with the same charge will repel each other. What will two materials with different charges do?

Give 3 ways you can reduce the chance of receiving an electric shock

Lorries that contain flammable gases, liquids or powders need to be earthed before unloading as friction can cause a build up of charge and lead to a spark which could then ignite the flammable substance. What ways are there of reducing the problems of static electricity?