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Introduction to Electricity

Physical Science - Middle School

Introduction to Electricity © Copyright NewPath Learning. All Rights Reserved. 94-4487 Visit for Online Learning Resources. Atoms & Elec tric Charges Atoms are made up of protons, neutrons and electrons. Protons are positively charged and electrons are negatively charged. Neutrons are not charged particles. repelled attracted Other materials, like plastic, are known as insulators, because their electrons will not easily move. Interaction of Charged Particles The interaction of electric charges is called electricity. If particles have opposite electric charges, they attract each other. If particles have similar charges, they repel each other. These interactions explain why an atom is held together. The positively charged protons in the nucleus exert a strong attraction for the negatively charged electrons that surround the nucleus. Electric Fields The attraction or repulsion that exists between charged particles is known as electric force. The area around a charged particle, where an electric force is exerted, is called an electric field. For a negatively charged particle, electric force lines are drawn pointing inward toward the particle. For a positively charged particle, the lines are drawn outward. The lines on the diagram are close together right next to the particle, where the field is the strongest. Multiple Charged Particles When two charged particles come close together, their electric fields are combined. The diagram on the left represents the electric fields of particles that are attracted. The diagram on the right shows the electric fields of particles that are repelled. The Movement of Electric Charges Objects do not normally have a positive or negative charge. However, within the atoms of some materials, the electrons are able to leave and move to other atoms. When an object gains or loses electrons, the object can become charged. Some materials, like copper and aluminum, are called conductors because their electrons can easily move. conductors insulators conductors insulators When the electrons have moved, the balloon becomes charged. Oxygen atom electron proton neutron nucleus + + + + + attracted repelled positive field negative field positive electric eld negative electric eld + positive electric eld negative electric eld + + + + + + + + + + + + + + + + + + + + +
Pause and Review Look for examples of things around your house and school that are conductors and insulators. List them below. Introduction to Electricity Conductors Insulators © Copyright NewPath Learning. All Rights Reserved. 94-4487 Visit for Online Learning Resources. ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________