2.20 Describe experiments to investigate how insulating materials can be charged by friction

• Rip up some pieces of paper
• Get  a plastic rod
• Without touching the paper, hold the rod over the pieces. It won't do anything.
• Then, rub the rod with a soft cloth. (The rod has been charged by friction now)
• Repeat step 3
• The pieces of paper will stick to the rod because it has been charged with friction.