Transcript Electric Charge

Electric Charge
Positive & Negative Charge
• Protons—positive charge
• Electrons-negative charge
Protons=electrons
• Atom becomes negatively charged when it
gains extra electrons
• Atom becomes positively charged when it
loses electrons
• Positively or negatively charged atoms are
called ions.
Electrons Move
• Electrons can move from atom to atom
and from object to object
• One way electrons can be transferred is
by rubbing
– Example: rubbing balloon on hair
• Hair loses electrons– “+” charge
• Balloon gains electrons– “-” charge
• Two items attract each other
• Imbalance of electric charge on an object
is called static charge
Electric Forces
• All charged object exert an electric force
on each other
• Charges can be attractive or repulsive
+
+
+
-
-
•
Electric force between two electric
charges depends on
1. Distance between two charges
2. Amount of charge on each
•
Electric charges exert a force on each
other at a distance through an electric
field
+
-
Insulators & Conductors
• Insulator—material in which electrons
cannot move easily from place to place
– Plastic, wood, glass, rubber
• Conductor—materials that contain
electrons that CAN move more easily
– Copper, gold, aluminum
Induced Charge
• Electric discharge—rapid movement of
excess charge from one place to another
– Lighting
– Spark that jumps between your fingers and
metal doorknob
• Grounding—process of providing a path to
drain excess charge
– Lightning rod—conduct electricity into ground
if rod is struck by lightning