# static electricity how would you define static electricity?

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• Slide 1
• STATIC ELECTRICITY How Would you define Static Electricity?
• Slide 2
• Electric Charge BASIC to all matter Different materials have different affinities for electrons.
• Slide 3
• Basic Facts About Atoms Every atom has a positively charged nucleus surrounded by negatively charged electrons. The electrons of all atoms are identical. Each has the same quantity of negative charge and mass. Protons have exactly the same magnitude charge of an electron but is opposite in its sign.
• Slide 4
• Slide 5
• When charged particles come near one another, they give rise to two different forces. A force can pull objects together or it can push objects apart.
• Slide 6
• Law of Electric Charge 1:Like charges repel one another 2: Unlike charges attract one another
• Slide 7
• Slide 8
• Why do balloons stick to the wall after being rubbed on hair or fur?
• Slide 9
• How Can This Happen?
• Slide 10
• Slide 11
• Static Electricity The buildup of electric charges on an object The electric charges build up because electrons have moved from one object to another.
• Slide 12
• Three Ways of Creating a Charge Rubbing two objects together-FRICTION-- TRIBOELECTRIC Conduction transferring a charge by TOUCHING Induction-- Inducing a charge-NOT TOUCHING
• Slide 13
• Friction Transfer of electrons by rubbing.
• Slide 14
• Slide 15
• Slide 16
• Rubbing Separates charges on Objects One object loses electrons while the other object gains these electrons. The object that loses electrons has an overall positive charge. ONLY THE ELECTRONS MOVE!!!
• Slide 17
• Slide 18
• A van der Graff Generator rubs electrons off a rubber band. These electrons are transferred to the dome.
• Slide 19
• Van de Graff Generator
• Slide 20
• CHARGING BY CONDUCTION Charging a neutral body by touching with a charged body
• Slide 21
• Conduction Conduction transfers the electrons to another object through actual contact.
• Slide 22
• What Is Happening?
• Slide 23
• Slide 24
• Conservation of Charge It is important to note that when we charge something, no electrons are created or destroyed.
• Slide 25
• Slide 26
• Charging by INDUCTION Charging an object by NOT Transferring Charges.
• Slide 27
• Slide 28
• Slide 29
• Slide 30
• Slide 31
• What are the charges doing?
• Slide 32
• Electric Fields Charged Particles have fields around them As the distance from a charged particle increases, the strength of the electric field decreases.
• Slide 33
• Coulombs Law q1q2 F = k d2
• Slide 34
• Electric Discharge The rapid discharge of electrons. Examples: Spark that jumps between your finger and a doorknob lightning
• Slide 35
• VOLTAGE Also known as POTENTIAL DIFFERENCE Voltage acts like a force in electrical circuits.
• Slide 36
• VOLTAGE Electrical Potential difference or energy per charge is called a volt
• Slide 37
• Separation of Charges Look at the picture: establish a relationship between Energy, Voltage and Distance for two charge plates..
• Slide 38
• Electricity may be defined as the energy associated with electrons
• Slide 39
• DANGER!!! STATIC CHARGES 200 years ago, young boys called powder monkeys ran below the decks of warships to bring sacks of gunpowder to the cannons above. It was the ship law that this task be done barefoot.
• Slide 40
• DANGER!! STATIC ELECTRICITY Always touch something metallic before grabbing the pump handle if you think you have built up a static charge.
• Slide 41
• DANGER!!! STATIC Never pump gas without discharging the static charge first
• Slide 42
• 1 Coulomb 6.25 X 10 18 electrons
• Slide 43
• Coulombs Law The amount of force the a tiny sphere with a charge q1 exerts on a second sphere of q2 is inversely proportional to the square of the distance. If I double the distance the force decreases to one fourth of the original force The Force between the spheres is directly proportional to the charge.
• Slide 44
• Coulombs Law q 1 q 2 F = k d 2 F=force k=9 X 10 9 N*m 2 /C 2 q 1 = 1 st charge in Coulombs q 2 = second charge d= distance in meters
• Slide 45
• Electric Field All charges create an area in all directions around it that an electric charge can be detected.
• Slide 46
• Electric Fields Electric Field strength measured in N/C E= F/q
• Slide 47
• Electric Field Lines Radiate from the positive charge to the negative charge. Defined by the path of a positive test charge.
• Slide 48
• Electric Field Lines Determined from + test charge
• Slide 49
• Electric Field lines Show forces around a point charge that go from positive to negative.