Week of March 16

Welcome to a new topic!  It is a very charged one!  

Electric Charge and Static Electricity!  

Big Idea - Forces between objects act when the objects are in direct contact or when not touching

I can...

• Recognize that the electrical force increases as electrical charges increase
• Recognize that the electrical force decreases when the distance between the charges increases
• Given a simple interaction between 2 objects not touching, identify objects, interaction, and direction of force on objects

Vocabulary:  electric charge, static electricity, electrical 

conductor, electrical insulator, semiconductor, electrical field 

and force, induction, current

---------------------------------------------------------------------------------------

What is electrical charge?

• Electrical charge is a property of matter!

• Electric charge involves electromagnetic interactions between particles of matter 
• Matter can be overall negatively, positively, or neutrally charged by the loss or gain of negative electrons
• Charged objects exert a force on each other even if they are not touching - this is called electric force
• How strongly the electric force pushes or pulls depends on the amount of charge and the distance between the objects
• Charging objects involves moving negative electrons from one object to another - but they are not lost - just moved
• Electric charge is always conserved - this means that the total amount of charges always remains the same - they just trade places 

• Objects with the same charge (like charges) - repel each each other
• Objects with different charges (unlike charges) - attract each other
• The closer the charged objects are, the stronger the electric force

How Do Objects Become Charged?

• Objects become charged when they gain or lose electrons
• This can happen 3 ways:  friction, contact, induction (charges are rearranged int he object without touching it)

What is Static Electricity?

You guessed it! The best example of static electricity is lightning!

Static Electricity is the build up of charges - lightning works likes this :

• During storms or windy conditions, negative charges (electrons) build up in the bottom of clouds due to friction mostly
• When enough negative charges build up, they induce or induction occurs and electric discharge happens in the form of lightning 

Conductor and Insulators

• Some materials are better conductors of electricity than others
• Most metals like copper are very good conductors - meaning they allow the charges to move freely 
• Other materials like plastics, rubber, and wood are not good conductors - but they are used to insulate metals that conduct electricity - this stops a lot of shocks and electrical fires!
• Semiconductors are a special type of conductor used in computer chips - their main material is silicon
• Semiconductors conduct electricity better than insulators but not as well as a material like copper - but they are perfect for usage in electronics 

Links:

Bill Nye Van de Graaff

Nat Geo Lightning