Electrostatics the study of electrical charges at restElectrodynamics the study of electrical charges in motion opposite positivenegativeBenjamin Franklin Two opposite types of charge exist, named positive and negative by Benjamin Franklin.Benjamin FranklinBenjamin Franklin Charge is a property of matter.

Charged particles exist in atoms. Electrons are responsible for negative charge; protons for positive charge; neutrons have no charge. Small amounts of ordinary matter contain incredible amounts of subatomic particles!

Choose an element on the periodic table. Iron has atomic number of 26. This means that there are 26 protons in each atom of iron. Assuming that the iron atom is neutral (no net charge), the atom will also have 26 electrons. The number below the element is the atomic mass. This number tells us that on average, each atom of iron has a total of protons and neutrons in the nucleus. Since there are exactly 26 protons in an atom of iron, on average each iron atom has neutrons. How is that possible? The number of neutrons in the iron atom can vary. Some isotopes of iron contain exactly 29 neutrons, some have 28, and some have 30. Different isotopes of iron may be expressed as Fe-55, Fe-56, Fe-57, etc... The atomic mass also tells us the mass in grams of one mole of iron.

Charged atoms are known as ions. An atom becomes charged by gaining or losing electrons. The charge of an ion is typically expressed as an exponent written after the atomic symbol. Cu +2 represents a copper atom with a +2 charge, which means that it is a copper atom that lost 2 electrons. Cu -1 represents a copper atom with a -1 charge, which means that it is a copper atom that gained an electron.

Let’s count the number of subatomic particles (protons, neutrons, and electrons) in a relatively small amount of an element. Let’s assume that a penny is pure copper and has a mass of 3.4 grams. Checking the periodic table, we find that the atomic number of copper is 29 and its atomic mass is atomic numberatomic mass This means that x atoms of copper (= 1 mole = Avogadro’s number) has a mass of grams, and each individual atom contains 29 protons, 29 electrons, and on average, neutrons.mole Avogadro’s number Therefore, the number of copper atoms in a 3.4 gram penny is found by multiplying Avogadro’s number by 3.4/ This value is then multiplied by 29 and to determine the approximate numbers of subatomic particles in the penny. How long would it take to count them????????

Conductor material that allows charges to move about easily Insulator material through which charges will not easily move Like charges repel; unlike charges attract Basic Law of Electrostatics:

Click here to read about charging objects by contact (friction). See shoes on carpet here. See a balloon on your sweater here. here View a simulation of charging a balloon by rubbing it on your hair and then sticking it to a neutral wall here. here

The SI unit of charge is the Coulomb, named in honor of Charles Augustin CoulombCharles Augustin Coulomb. Charles Augustin Coulomb 1 C = charge on 6.25 x electrons (or protons) 1 e - = 1.60 x Coul = elementary charge How many Coulombs of negative charge are contained in that copper penny?

COULOMB’S LAW The force between two charged objects is directly proportional to the product of their charges and inversely proportional to their separation distance squared. link1link1, link2, link3, link4, link4link2link3link4

In equation form: F  F is the force of attraction, measured in NEWTONS, between charges q 1 and q 2 k k is the Universal Electrostatic Constant, equal to 9.00 x 10 9 N m 2 /coul 2 q1q1 q2q2 q 1 and q 2 are the attracting charges, measured in Coulombs d2d2 d is the distance between the charges, and is measured in METERS

Electric Fields An electric field exists in a region if space if a charge placed in that region experiences an electric force. The magnitude of an electric field at any given point is defined to be the ratio of the force on a charge at that point to the amount of charge. E = F/Q Electric field strength has units of Newtons/Coulomb (N/C).

The direction of the electric field at any point is defined to be the same direction as the direction of force on a positive test charge placed in the region at that point. Field lines point away from positive charges and toward negative charges. Investigate electric fields due to point charges at the simulation here. here

Click here to view a simulation showing the magnitude and direction of the electric force on a test charge when placed near other charges. here Click here to view a simulation of a charged particle moving through a region occupied by other charges. here

Electric Potential Difference the change in electric potential energy per unit charge V = W/QV = W/Q The SI unit of electric potential VOLT difference is the VOLT, named in Alessandro Volta Alessandro Volta honor of Alessandro Volta.Alessandro Volta One VOLT is the electric potential difference between two points when one Joule of work is done in moving one Coulomb of charge between the points.