Static Electricity Powers Real Devices

Static Electricity Powers Real Devices

Year 7 Physics Exploring electrostatic phenomena and practical applications 60-minute lesson

What Do You Already Know?

Have you ever experienced static electricity? What happens when you rub a balloon on your hair? Why do you get shocked touching metal after walking on carpet?

What is Static Electricity?

Electric charge that builds up on surfaces Caused by friction between materials Electrons transfer from one object to another Creates an imbalance of positive and negative charges

Positive vs Negative Charges

{"left":"Objects that lose electrons become positively charged\nObjects that gain electrons become negatively charged","right":"Like charges repel each other\nOpposite charges attract each other"}

Demonstration: Balloon and Paper

Rub a balloon on your hair or clothing Hold the balloon near small pieces of paper Observe what happens to the paper Explain why the paper moves toward the balloon

The Van de Graaff Generator

Machine that produces large amounts of static electricity Uses a moving belt to transfer charge Can create voltages of hundreds of thousands of volts Invented by Robert Van de Graaff in 1929

How a Van de Graaff Generator Works

Safety with High Voltage

Van de Graaff generators produce high voltage but low current Generally safe for demonstrations Always use proper safety equipment Never touch the dome while it's operating

Thought Experiment: Hair Standing Up

Imagine touching a Van de Graaff generator dome Your body becomes charged with the same charge as the dome Each hair strand has the same charge Like charges repel - hair strands push away from each other

Rapid Discharge and Sparks

When charged objects get close to grounded conductors Electrons jump across the air gap Creates visible sparks and crackling sounds Air becomes temporarily conductive

Earth Connection Demonstration

Connect a metal probe to the ground (earth) Bring the probe near the charged Van de Graaff dome Observe the spark that jumps to the grounded probe Explain why grounding provides a path for charge to escape

Static Electricity in Everyday Life

Photocopiers and laser printers use static charges Spray painting uses electrostatic attraction Air purifiers remove particles with static charge Lightning is nature's static electricity discharge