On-Line Lessons

Lesson I

STATES OF MATTER

Any beginning study of electricity must begin with an understanding of the states of matter. Matter can exist in three basic states, solid, liquid and gas. Although other states representing transitions between the fundamental ones are also possible. Matter also can exist in subdivided forms. Let's begin by characterizing the three basic states of matter.

Solid:
The substance has a given shape and volume no matter what type of container it is placed in. (Ice)

Liquid:
The substance changes its shape to fit the container in which it is put. (Water)

Gas:
The substance changes both its shape and volume to match the container into which it is placed.
(Water Vapor)

1.1 Everything we know is composed of matter. The earth's surface is matter in the solid form. The Great Lakes are matter in the liquid form and the air we breathe is a gaseous form of matter.

1.2 A bar of gold with a given volume will have the same shape in two different locations. We characterize solids by the fact that they retain their own shape and volume wherever they are placed.

1.3 If we heat the bar of gold to its melting point and pour it into a container it assumes the shape of the container, but it will retain its own volume therefore, a liquid is a state of matter which retains its volume but can change its shape.

1.4 If a substance changes states from liquid to gas to a solid, or vice versa its mass and weight remain the same. Example, if you buy a 5Lb. bag of ice and allow it to melt the ice will change states, solid to liquid, the weight of the water will be 5lbs.

1.5 The same mass of water, if vaporized to steam, will have a weight of 5 lbs.

Questions

1) List the three states of matter. Liquid, Gas, and Solid

2) Describe the characteristics of each state. Solid State retains it shape and volume. Liquid State retains its volume but can change shape. Gaseous State, changes its shape and volume to match the container.

3) List examples of matter in each of the states. Ice solid, Water liquid ,Water Vapor gaseous

Back to top

Lesson II

Elements, Compounds and Mixtures

An Element cannot be broken down into a simple substance and retain the original characteristics. Copper (Cu) and Silver (Ag) two good conductors are elements. They cannot be broken down any further without destroying their properties. Compounds are formed when elements are chemically combined so that they cannot be separated from each other by simple physical means. A chemical reaction is required to recover elements from a compound. A Mixture is a temporary combination of elements and separation by physical means is possible.

No matter what we do to a sample of Copper (Cu) it will still remain Copper. No known physical or chemical process can break Gold (Au) down into a simpler substance, therefore, Gold is an element.

A compound is a substance that will be produced when two or more elements combine. Iron rust is a combination of iron and oxygen; hence Iron rust is a compound.

The combination of Sodium and Chlorine (Na Cl 2), common table salt, are bound to each other in a way that a chemical reaction is needed to separate them from each other. Ordinary sugar is made up of carbon, oxygen and hydrogen united to each other chemically. These substances are, therefore compounds.

The elements Carbon and Sulfur, in addition to Potassium Nitrate combine to make gunpowder. If water is filtered through gunpowder the nitrate is dissolved out leaving the carbon and sulfur behind. Gunpowder is, therefore, a mixture.

Questions

1. Define Elements, Compounds and Mixtures listing their characteristics and differences.

2. List examples of Elements, Compounds and Mixtures.

| Home | Refrigeration/Air Conditioning | Electronics |  About Us | Cool Sites | Why choose ETI

| American Title Service

Back to top

Lesson III Atoms and Molecules

The structure of atoms are made up of at least 30 different fundamental particles. We shall confine our attention to only three of them: Protons, Neutrons, and Electrons. The central part of an atom is called the nucleus, in which the proton and neutrons are located. The electrons are visualized as being in planet-like orbits around the nucleus.

Identical atoms together form the elements. Copper atoms bound together form the solid state. Oxygen contains atoms bound together to form a gas. Mercury contains atoms bound together to form a liquid.

The building block of an element such as gold are the atoms of which it is composed.

When water is broken down to smaller size of particles, we end up with a molecule containing 1 atom of oxygen and 2 atoms of hydrogen.

A molecule is defined as the smallest particle of a compound that will retain the properties of the original compound. Table salt is a compound that can be broken down to its smallest particle size we will obtain a molecule with 1 atom of chlorine and 1 atom of sodium.

The atom can be broken down into three basic particles. They are: Protons, Neutrons, and Electrons. In the study of electronics the electron is the most important of the basic particle. The simplest atom, hydrogen, contains 1 proton at the center nucleus and 1 orbiting electron revolving around the nucleus. The helium atom is made up of 2 protons and 2 neutrons in the nucleus and 2 electrons in orbit around it.

The nucleus of the atom contain protons and neutrons while the electrons are in orbits revolving around the nucleus.

One atom of oxygen and two atoms of hydrogen can be combined to form one molecule of water.

Atoms of hydrogen normally tend to cling together to form a larger, stable particle. This particle would be called a (n) molecule of hydrogen.

Quiz

1) Define an atom and give an example.

2) Define a molecule and give an example.

3) Draw a model of an atom and name the basic particles.

Back to top

 Lesson IV Electrostatic Forces 

Forces of attraction and repulsion can be set up between bodies by treating them in certain ways: These forces are electrical in origin. Two bodies treated in exactly the same manner repel each other; two bodies treated in a different way can be made to attract each other these treatments being quit specific in nature. A rubber rod rubbed with fur. A force of attraction is often found between different substances treated in different ways. As an example, a glass rod rubbed with silk attracts a rubber for rubbed with fur. We compare all substances that share attraction and repulsion to fur-treated rubber and silk-treated glass. Fur-treated rubber repels fur-treated rubber and silk-treated glass ___________________ silk-treated glass but, silk-treated glass will__________ fur-treated rubber. If a rod repels a fur-treated rubber rod it will, therefore,__________ a silk-treated glass rod. If a rod attracts a fur-treated rubber rod it will, therefore,__________ a silk-treated glass rod.

Quiz

1) Determine when two bodies will attract each other due to electrostatic force.

2) Describe how one can demonstrate that two bodies can repel each other due to electrostatic force.

Lesson V

A single electron will produce the "-" charge, while the "+" charge is the charge of a single proton. A body is net positive if it has more protons than electrons. This is caused by the addition of an electron which produces a negative Ion or the absent of an electron which produce a positive Ion. To determine the numeric value of the net charge you would subtract the number of one type of charge from the number of the other type. If there are more electrons than protons then the net charge is negative, if there are less electrons more protons, then the net charge would be positive.

A single electron will have one unit of negative charge; therefore 4 electrons have_____________ units of_______________ charge. The proton is the unit of positive charge. A single proton has one unit of positive charge; therefore, 7 protons have____________ units of ____________ charge. The charge of an electron is the same magnitude as the charge of a proton; but opposite polarity. If one electron is offset by one proton they will cancel each other, resulting in a net charge of zero. If a body contains 2 more electrons than proton it can be made neutral by removing 2 electrons or by adding 2 protons. Therefore, a body with 5 more protons than electrons can be made neutral by adding____________ electrons. Under normal conditions an atom will have an equal number of electrons and protons. Since normal atoms contain and equal number of electrons and protons they are neutral or have no charge. If we force an electron from the valance orbit of an atom that atom will now contain more "+" charged proton than"-" charge electrons and is no longer neutral but will be positively charged. If an electron would enter the valance orbit of an atom then the atom would contain one more electron than proton and the atom would be negatively charged. A neutral atom of copper (Cu) will have 29 protons in its nucleus and ____________ electrons in orbit around the nucleus. A silicon atom contains 14 protons and 14 electrons in its neutral state therefore, a silicon Ion with a positive charge could contain ____________ electrons. If an Ion has a net negative charge of 2 it must lose 2 ________________ to become neutral again. If a neutral atom gains or loses 2 or more electrons, it is said to be doubly ionized and if the gain or loss is one electron, it is singly ionized. A singly charged positive Ion that takes on one additional electron becomes a ___________ atom. For a doubly charged negative Ion to become a neutral atom it would have to give up __________ __________.

Quiz

1) An atom of sodium contains 11 protons, 12 neutrons, and 11 electrons. Its net charge is _____.

2) Define the unit of negative charge.

3) Define doubly ionized.

Back to top

To request info click here: Course Information