Electricity Part 1: Atomic Structure Review Part 2: Electrostatic Charge

Warm Up - Electricity In your group, you should discuss the results of the Balloon Inquiry from the last class. Where any of the results surprising? What do you think is causing the phenomenon observed?

Review of Atomic Structure Atomic structure, containing subatomic particles

Atoms contain neutrons, protons, electrons Electrical force based on electric charge interactions Like charges repel, unlike charges attract Electricity involves transfer of electrons electron – negatively charged subatomic particle, word based on Greek work for amber Review of Atomic Structure

atoms – electrically neutral Atoms can become ions, charged particles (more about why in later chapters) Lose electrons, become cation Gain electrons, become anion Atomic Charge

Electric charges result from gain or loss of electrons Electrostatic charge- confined to object, not moving We often call this static electricity Electrostatic charge

Electrostatic Charge

Magnitude of an electric charge is identified with number of e- that have been transferred Coulomb (C) is quantity of charge (q) fundamental unit like meter, kg, second e- has a charge of -1.6 x C p+ has a charge of +1.6 x C fundamental charges - charges on objects are multiples of these charges Measuring electric charge

Size of electrical force depends on amount of charge (q) of each object and distance between them F = k q 1 q 2 d 2 Where k = 9.0 x 10 9 newton meters 2 /coulomb 2 Strength of force decreases if distance increases How does this relate to our activity yesterday? Coulomb’s law

Electric Field Model of a field Lines always point away from positively charged particle and in towards negatively charged particle Spacing shows stronger field where lines closer together