Electricity Electric Charge and Static Electricity
Electric Charge Charged parts of atom Protons: positive charge Electrons: negative charge Atom Visualization Positive charges repel each other Negative charges repel each other Charges that are different attract each other Electricity: the interaction between electric charges
Electric Force The attraction or repulsion between electric charges Electric Field Invisible region around a charged object where the object s electric force is exerted on other charged objects If another object is placed in the way it will either be pushed away or pulled toward that charged object Single Charges The greater the distance, the weaker the electric field The closer the field lines, the stronger the electric field Electric Force Field Visualization
Multiple Charges The electric field will be altered when there is more than one object The electric fields of each individual charge combine by repelling or attracting
Static Electricity Typically, atoms are neutral because they contain an equal number of protons and electrons Some objects can become charged Protons are bound tightly in the center of an atom but electrons can leave their atoms If an object loses electrons, it has an overall positive charge If an object gains electrons, it has an overall negative charge The buildup of charges on an object is called static electricity In static electricity, charges build up on objects but they do not flow continuously
Transferring Charges The Law of Conservation of Charge: charges are neither created nor destroyed. If one object gives up electrons, another object gains those electrons. Charging by Friction Charging by Conduction Charging by Induction
Charging by Friction Occurs when two objects rub together Object that gains electrons becomes negatively charged Object that loses electrons becomes positively charged
Charging by Conduction Occurs when two objects touch Electrons transfer from the object that has the more negative charge to the object that has the more positive charge This means that a positively charged object will gain electrons when it touches an uncharged object
Charging by Induction Objects do not touch when charges transfer The movement of electrons to one part of an object that is caused by the electric field of a second object The electric field around the charged object attracts or repels electrons in the second object
Static Discharge Electrons have a tendency to move, returning the object to its neutral condition Static discharge is the loss of static electricity as electric charges transfer from one object to another This means that when a negatively charged object and a positively charged object are brought together, electrons transfer until both objects have the same charge
Static Discharge Will often produce a spark When electrons transfer objects, they heat the air around the path they travel until it glows The glowing air is the spark you see Interactive Example: Static Electriciy & Discharge Lightning - huge spark of static discharge Occurs to restore a neutral condition in the clouds Electrons move from areas of negative charge to areas of positive charge Will reach Earth when negative charges at the bottom of the storm clouds cause the surface of the Earth to become positively charged by induction Electrons will jump between the cloud and Earth s surface, which occurs through conduction
Links & Clips Mythbusters Part 1 Mythbusters Part 2 Brainpop! Static Electricity
Section 1 Vocabulary Electric force Electric field Static electricity Conservation of charge Friction Conduction Induction Static discharge