Dr Pusey

www.puseyscience.com

Recap of the atom

An atom consists of a nucleus containing protons (positively charged) and neutrons (no charge).

Electrons are present in the region of space outside the nucleus. They are negatively charged and weakly bound to the atom.

From: http://blog.ssis.edu.vn/103059/2013/09/17/does-the-color-of-hair-affect-how-much-static-electricity-it-can-carry/

Static Electricity When an object has an imbalance of

protons and electrons

More protons gives it a _________ charge

More electrons gives it a _________ charge

Lightning

Charge imbalance between clouds and the earth

Eventually, the charge is equalised with a massive “spark”

Scientists still don’t fully understand this mechanism

Lightning in slow motion

Charge Imbalance NOT CAUSED BY FRICTION –

correct your friends!

Caused by the Triboelectric Effect:

Some materials will keep hold of the electrons when pulled apart from another material.

This depends on the materials used

Negative

Plastic

Polyester

Hard Rubber

Cotton

Paper

Silk

Fur

Wool

Hair

Glass

Positive

Which materials keep hold of charge

Charges

Neutral = no overall charge

Opposite charges attract, like charges repel

How static builds up

Two perfectly neutral objects just sitting around doing nothing interesting

When they make continued contact and separation, the cloth keeps all the electrons

The rod now has more protons than electrons, and is positively charged

Describe what would happen if two positively charged rods were brought together

Like Charges Repel

Q: Describe what would happen if the cloth were brought back near the rod

Opposite Charges Attract

Q: If the water is neutral - Describe how this is working!

http://www.thenakedscientists.com/HTML/experiments/exp/bending-water-static-attraction/

Opposite Charges Attract

Answer: The negative charges of the balloon repel the water’s electrons away, which make an area of the water positively charged. This is then attracted to the negatively charged balloon! This positive charge on the water is called an induced charge.

http://www.thenakedscientists.com/HTML/experiments/exp/bending-water-static-attraction/

Recap

What IS static electricity?

What CAUSES static electricity?

Name 3 examples of static electricity

Recap

What IS static electricity?

The imbalance of electrons and protons causing a net or resulting charge on an object

What CAUSES static electricity?

Triboelectric effect, where electrons are passed from one object to another after making contact. Material dependent.

Name 3 examples of static electricity

Lightning, bending water with a balloon, feather dusting, clingy clothing being in the dryer