Knowledge of electrical charges throughout history: Origin of word electron (Greek word for amber); discovery of two types of charge: Positive and negative; like charges repel and unlike charges attract; Ben Franklin discovers conservation of charge, existence of conductors.

Charging a glass rod with silk, then inducing a polarization of charge in a conductor. Properties of conductors. Demonstration: Using balloons to demonstrate induction of positive and negative charges with conductors and non-conductors.

Friction creates a charge when combing your hair, touching a doorknob after walking on a carpet, using Saran™ Wrap and cellophane. Experiment: Beating a student with cat fur to create a charge, then discharging by touching a neon discharge tube.

Demonstration of a Van de Graaff generator used to charge confetti, causing it to jump in the air.

Force of one charge on another charge is Kqq/r^2, unit is Coulomb. A Coulomb is very large, electron has charge 1.6E-19 C. Coulomb's constant K = 9E9 N*m^2/C^2=1/(4pi*epsilon_0). Electrical force between two charges is analogous to force on two masses due to gravity. With 3 or more charges the force on one charge from the other two is the sum of the individual forces.

Definition of electroscope as a device for measuring charge. Demonstration of human electroscope by charging himself with the Van de Graaff and holding pieces of tinsel.

Electric charge and electric force defined. Coulomb's Law with an example. The Superposition Principle for charges.

Electric potential; Lorentz force and magnetic force; Biot-Savart Law; magnetic dipole moments

Definitions, with equations. Superposition, charge densities, and unit vectors are also defined.

Electromagnetism through history; standard model; electric charge.

Statement; superposition for point charges and distributions; SI vs. cgs units; force from charged rod; Taylor expansions.

Work required to move charge; potential energy of configuration.

Definition; examples and equations; sources, sinks, and circulations; example of gravity, electric, and magnetic fields.

Definition and equation; Van de Graaff generator; superposition of electric forces with example.

Four questions about induced charges on hollow conductors, with answers and explanations.

Calculating charge necessary for two dust grains to overcome gravitational attraction.

Solution (PDF)

Finding ratio for electron and proton; distance to balance; gravity on large scales.

Solution (PDF)

Ratio of electric to gravitational forces between earth and moon for smaller electron charge; stable system.

Solution (PDF)

Finding force on central point charge before and after an outer charge is removed.

Solution (PDF)

Finding position of third charge for F = 0; potential energy of third charge and effect of perturbation.

Solution (PDF)^#

Determining experimentally whether an object carries a purported third charge.

Solution (PDF)^#

For triangular arrangement of charges, finding the E-field, the force on a charge, and the motion of a charge.

Solution (PDF)^#

Video animation showing the interaction of four equal charges: Two positive and two negative. Mention of Pauli and van der Waals forces.

Applet simulating the interaction of large numbers of positive and negative charges in a two-dimensional space.

Applet simulating the interaction of large numbers of positive and negative charges in a three-dimensional space.

Interactive applet simulating the interactions of charged particles in a two-dimensional space.

Interactive applet simulating the interactions of charged particles in a three-dimensional space.

Interactive applet simulating the behavior of two lattices of charged particles as they collide with one another.

Applet simulating the interaction between 10 positively charged particles contained in a pentagon.

Applet simulating the behavior of the charges inside the plates of a parallel plate capacitor.

Applet simulating the behavior of a conducting sphere placed between the plates of a parallel plate capacitor as it is being charged

Interactive applet simulates interaction between charged particles, with ability to view field lines and equipotential lines for the particles.

Applet in which the player tries to navigate a simple maze by changing the value of a point charge between positive and negative.