PS-6.5 How can objects acquire a static electric charge through friction, induction, and conduction.

To understand some basic electrostatics we must first understand the following:

1.All matter is made up of atoms.

2. Atoms are made up of three types of particles: protons, neutrons, and electrons.

3. Two of the particles in atoms are electrically charged.

4. The protons, which are tightly held in the nucleus, are positively charged.

5. The electrons, which move around outside the nucleus, are negatively charged.

6. Atoms normally have the same number positive charges as negative charges. The effects of these charges cancel out and the object will have no net charge.

6 positive Protons plus 6 negative electrons equals 0 net charge!

The electrons in the atoms can be knocked off and move onto something else.

Rub a wool cloth briskly across the surface of the rubber rod and the rod will pick up electrons.

Rub a wool cloth on a balloon and the balloon will pick up electrons from the atoms of the wool cloth. The balloon will now have a negative electrical charge.

Negatives repel negatives.

Like charges repel each other.

Positives repel positives

Opposite charges attract.

Negatives attract positives and positives attract negatives.

The attraction is mutual !

This atom has a balance of electrical charge, 6 Positively charged Protons and the same number of negatively charged electrons. The net charge of the atom is 0.

When this same atom has an electron removed it becomes positively charged. It has one less electron than Proton.

When an objects atoms lose electrons it will have more protons than electrons and will have a net positive charge.

If the atoms of an object lose electrons it will have fewer electrons than protons and will have a net positive charge.

The wool cloth lost electrons to the balloon. The cloth now has a net Positive charge.

If an object gains electrons it will have more electrons than protons and will have a net negative charge.

The balloon gains negative charge. It now has a net negative charge!

Objects can get an electric charge by:

Friction: If you rub one against another, sometimes electrons leave one object and stick to another leaving both objects charged.

Conduction: Electrons can be transferred from one object to another by touching.

When a charged object touches another object some charge will transfer to the other object. It is always the electrons that move in solid objects.

Objects charged by conduction will have the same charge as the object charging it therefore will repel it.

Induction: Objects can be charged by bringing a charged object near a neutral object.

If a charged object is brought near a neutral object the charged object will attract unlike charges in the neutral object and repel like charges in the neutral object.

After an object is charged by induction it will have a charge opposite the charge of the charging object and will attract it.

This presentation is online at www.mrdavenport.com

THE ENDFor now