ELECTROSTATICS Electrostatics J J Thomson discovered negatively charged

ELECTROSTATICS Electrostatics

• J. J. Thomson – discovered negatively charged particles which he called electrons History • Ernest Rutherford – discovered that the nucleus is positively charged.

Charges • Protons have positive electric charge • electrons have negative electric charge • Atoms become charged by gaining or losing electrons

Charged objects • Have an uneven number of protons and electrons

Electrostatic s of • the study electrical charges that can be collected and held in one place

Electrical Laws • Law of conservation of charge – charge may be transferred from object to another object, but it cannot be created or destroyed

Electrical Laws • Opposite charges attract, and like charges repel • Charges can act on each other even at a distance

• Electrons move more easily through conductors, like metals. • Electrons do not move easily through insulators, such as plastic, wood, rubber, and glass

Transferring electric charge • Charging by contact (conduction) – the process of transferring charge by touching or rubbing – Example: static electricity from your feet rubbing the carpet

Transferring electric charge • Charging by induction: – The rearrangement of electrons on a neutral object caused by a nearby charged object – Example: a negatively charged balloon near your sleeve causes an area of your sleeve to become positively charged

Static Discharge • A transfer of charge through the air between two objects because of a build up of static electricity • Example: lightning

Electroscopes detect charges • When a negatively charged object touches the electroscope, the leaves become negatively charged and repel each other.