Learning objectives To be introduced to the law of electric charges To understand the basics of electrical attraction

Create a Concept Map about Electricity Start with the word “electricity” in the centre of a large piece of chart paper. Add categories, terms, concepts, diagrams and sketches to the map, making links between the parts that are connected.

What do you already know? True or False in the following statements? Electricity is the flow of particles called protons Objects with the same charge will be attracted to one another A substance in which electrons are able to move freely is called an insulator Lightning is a form of static electricity Light bulbs are very efficient at converting electrical energy into light energy Coal, petroleum, and natural gas are all renewable energy sources Natural gas is the least harmful fuel in terms of the environment Appliance plugs have 3 prongs so if one breaks off it is still useable A negatively charged object has more protons than electrons Static electricity tends to be worse in the winter because the air is drier Clothes get static cling in the dryer because they rub together and electrons move from one piece of clothing to another Electric circuits are all built the same way in your home Static electricity is a useful form of electricity Furniture gets dusty because of static electricity It is possible for an appliance to be 100% efficient if it is kept in good working order.

Remember…. Protons have a positive charge Protons are located in the nucleus of an atom Protons are held in place by very strong forces

Remember…. Electrons have a negative charge Electrons are located in orbits around the nucleus Electrons can be added to or removed from an atom

Remember…. Atoms have balanced positive and negative charges and are therefore neutral Atoms with unbalanced positive and negative charges carry an electric charge Electric charges can exert electric forces

Characteristics of Electricity Unit 1

Some Terminology Charge symbols are used to represent large numbers of protons (+) and large numbers of electrons (-) An object’s overall electric charge can be determined by comparing the numbers of charge symbols drawn on the object

A Neutral Object….. Has equal numbers of + and - charges

A negatively charged object…. Has more electrons (-) than protons (+)

A Positively charged object… Has fewer electrons (-) than protons (+)

Static Electricity – Chapter 10

What is Static Electricity? http://ed.ted.com/lessons/the-science-of-static-electricity-anuradha-bhagwat?utm_source=TED-Ed+Subscribers&utm_campaign=ebd0154a59-2013_09_219_19_2013&utm_medium=email&utm_term=0_1aaccced48-ebd0154a59-47581293

Static electricity is…. an imbalance of electric charges on the surface of an object. It is called static because the charges rest on the surface

How do objects become charged? Almost all objects are neutral Charging occurs when electrons move from one object to another Protons don’t move. Ever!

When electrons on object A move to object B, object A becomes positively charged and object B becomes negatively charged. Let’s draw that….

The Law of Electric Charges 1. Like charges repel 2. Unlike charges attract Electric force can be either an attractive force or a repulsive force Charged objects will attract both neutral and unlike charges Charged objects will only repel objects with like charges

The strength of the attraction or repulsion (electric force) is related to two things: 1. The amount of charge on each object (force increases with increasing charge) 2. The distance between the objects (force decreases with increasing distance)

Why are neutral objects attracted to charged objects? A charged object coming close to a neutral object induces the electrons in the neutral object to shift The law of electric charges determines which way they shift This shift is called induced charge separation

Questions...... Page 398 # 1 – 5 Page 401 # 3, 4, 5

Using Static Charges (Pg 470) Static electricity may be used to our advantage Electrostatics deal with static charges and static electricity Static electricity has many useful applications For example: electrostatic paint sprayers and photocopiers