Lesson 14: How Bearings Increase Efficiency (How Things Work)

In this lesson, we will analyze how rolling element bearings aid mechanical components and increase efficiency by reducing friction. These rolling element bearings are found in almost every mechanical device which involves rotation. They are found in cars, carts, windmills, and even yo-yo's.

These bearings function on the principal that it is easier to roll something as opposed to slide something. To verify this, take something flat like a book and push it across a flat surface such as a table. Note how much force is required to push the book. Then place the book on a few cylindrical or spherical objects such as marbles or pencils. Now push the book and notice how much easier the book moves.

When objects slide across surfaces, the force of friction resists e object's motion. However, when something rolls, there is relatively no sliding occurring, so the resistant force of friction is minimized.

Rolling element bearings exploit this fact by placing round objects between two surfaces which would normally come in contact with each other with sliding motion. The inner surface of a rolling element bearing is known as the inner race while the outer surface is known as the outer race. The rolling elements are usually kept separated to reduce sliding with one another by a metallic structure called a cage.

Below is a picture of what a rolling element bearing might look like.

Lesson 13: How a Light Bulb Works (How Things Work)

Most people forget that at night, the light they enjoy is made possible by the invention of the light bulb. I thought, for our first lesson in how stuff works, we could analyze something relatively simple, but very important in our everyday lives.

Most people know that a light bulb requires power to function, and as a result, it outputs light and a little bit of heat. However, a significant portion of people do not know how this power is converted into light and heat, so today, we will discuss the mechanisms which make the light bulb work.

In a light bulb, there is a very thin wire usually made out of tungsten which is called the filament. When electrical current is passed through this filament, resistance is created. In our house, the wires connecting electrical appliances are relatively thick so the electricity can pass through them easily. When this current passes through the thin filament the electricity is forced through a small, thin path. Think of a crowd of people trying to fit through a small door all at once. This is called Resistance which causes the filament to burn.

In the light bulb, there is no gas, this is called a vacuum. This vacuum prevents the filament from oxidizing or destroying itself when electrical current is passed through it. This in turn keeps the filament white hot, which provides the light we use every night.

We have all had experiences with hot light bulbs, usually ending up in discomfort or burns. This heat can be thought of as inefficiency. When turning on a light bulb, we only want to light our house, not heat it, so this heat is a loss of energy and is inefficient. Currently, light emitting diodes, or LEDs, which are a type of light, put off very little heat and can be very bright for the amount of current passed through them. These are thought of as highly efficient lights and are being used in more and more applications.

For more information on light bulbs, check out:

1. http://en.wikipedia.org/wiki/Light_bulb
2. http://www.ideafinder.com/history/inventions/lightbulb.htm

Lesson 12: Chemical Reaction Equations (Chemistry)

In this lesson, we will discuss the equations which are used to describe chemical reactions. These are a vital part of the study of chemistry because the equations illustrate how substances react and what the reaction produces. Don't worry thought, these equations are extremely easy to understand and only simple math is required to work with them at this point.

An example of a reaction equation would look like this: 2H2 + O2 --> 2H20.

This is a relatively simple equation which describes hydrogen burning in the presence of oxygen to form water. In the reaction equation, the --> can be thought of as saying "reacts to form". The components on the left of the --> are the ingredients of the reaction which are called the reactants. The reactants interact to form the components on the right of the --> which are called the products.

In reaction equations, there are two types of numbers involved, coefficients and subscripts. The coefficients, like the first 2 in both 2H2 and 2H2O, are used to balance the reaction equation so the number of atoms on the right side of the equation will equal the number of atoms on the left side of the equation. Think of the coefficients as saying 2 H2 molecules or 2 H2O molecules. This is necessary because we know matter can not be created or destroyed so an unbalanced equation does not accurately depict a legitimate chemical reaction.

Due to text limitations in blogger, think of the second 2 in 2H2 and 2H2O and the 2 in O2 as being subscripts or small numbers located near the bottom of the line. These represent multiple atoms bound to another atom. Think of the molecule H2O. There are two hydrogen atoms bound to the oxygen atom. Subscripts can be thought of as numbers which tell us how the molecules involved in the reactions are constructed as opposed to how many of those molecules are involved in the reaction.

Reaction equations are used to predict not only what products will be produced from a reaction, but how much of those products will be produced. In the following equation, Mg + 2Cl --> MgCl2, we know, if we put in 100 atoms of Mg and 200 atoms of Cl, we will receive 100 atoms of MgCl2. Chemists do not calculate exactly how many atoms are used and will be formed, but rather, the measurement of mols is used in conjunction with chemical reaction equations. We will cover this in later lessons.

More information on chemical reaction equations can be found at:

1. http://en.wikipedia.org/wiki/Chemical_equation
2. http://www.science.uwaterloo.ca/~cchieh/cact/c120/reaction.html

The second link is helpful but covers topics that we have not yet discussed so if you aren't sure what is going on, don't worry, we will cover it in later lessons.

Lesson 11: The Periodic Table

In the previous lesson, we learned about the construction and composition of atoms, so in this lesson, we will learn how to read the periodic table of elements which is a Chemist's most important tool. This table, depending on how detailed it is, gives readily used information needed for calculations in chemistry.

Due to the complexity of the table, I won't draw one, but rather provide you with links to various tables. The former link leads to a basic table coupled with large amounts of additional. The latter link offers a very detailed table which would be more useful in more complex chemistry.

1. http://en.wikipedia.org/wiki/Periodic_table
2. http://www.dayah.com/periodic/

In this table, each element is represented by an abbreviation of one, two, or three letters. Some abbreviations correlate with the name of the element, such a C for carbon, but some represent Latin elemental names such as pb for lead.

Typically above each abbreviation is some whole number. This is called the atomic number and represents the number of protons in the nucleus of the atom. This number also represents the number of electrons in the atom if it the atom has an overall charge of zero.

The number below the abbreviation which is a number with some decimal is the average atomic weight of the atom. This number is the mass of the different isotopes for the element averaged together in terms of their abundances. Recall that from our last lesson, we established that one element is capable of having atoms of different masses because the atoms can have different amounts of neutrons. This number is used when the number of mols of atoms is being converted to mass. We will cover this more in detail later.

This table expresses many more traits of the elements being represented and we will cover these as we progress.

If you find this interesting, feel free to try to memorize the elements and associate them with their abbreviations. In chemistry the atomic abbreviations come up frequently so memorization would speed things up down the road. Otherwise, for occasional, casual chemistry, a periodic table can be referred to for abbreviations and elements.

Lesson 10: Composition of Atoms and Their Charge

Since we have been covering a lot of physics and math, why don't we try a few lessons in Chemistry. Before we can delve very far into the study, a basic knowledge of atoms and their components is required. So today, we will learn about how atoms are constructed, what each component of an atom is, and the charge of each of these components.

Atoms are comprised of 3 components. They are protons, neutrons, and electrons. So, to get a better understanding of what these are and what their function is, let's go through a description of each one.

1. Protons - These are located in the small nucleus of the atom along with the neutrons. They have a charge of +1. In order to remember this charge, it is often helpful to associate proton with the word positive. Protons, along with neutrons are relatively heavy particles.
2. Neutrons - These particles are also located in the nucleus of the atom along with the protons. These particles have no charge but a significant mass.
3. Electrons - These are particles with very little mass and are located in orbit around the nucleus. They move so fast that they can be thought of as forming a cloud around the nucleus. This is often referred to as the electron cloud. Electrons have a charge of -1.

It is important to remember that in a neutrally charged atom, there are as many electrons as there are protons. Think of this as adding all the individual charges up which will sum up to 0. However, the amount of neutrons can be different, even within the same type of element. Isotopes are atoms with a consistent amount of protons and electrons, but with different amounts of neutrons.

With this understanding of how atoms are constructed, we are prepared to learn about how they interact and bond to each other.

For more information, check out the following link: http://en.wikipedia.org/wiki/Atomic_structure

Lesson 9: Right Triangles and the Pythagorean Theorem

So far, we have covered a lot of physics so today, I thought we would look into a little math, more specifically, trigonometry. You might be asking why we are covering this or even why triangles are so important in the first place. The reason is, most geometric shapes can be broken down into numerous triangles for easier calculations which makes everyone's life a little easier. Think of a hexagon, square, octagon. These shapes occur frequently and can be broken down into individual triangles. Additionally, a lot of higher math and physics require vector analysis which requires a substantial amount of trigonometry.

The most basic type of triangle is called the right triangle. Its name states that the triangle contains one right angle which is a 90 degree angle. These types of triangles are the easiest to work with due to the fact that they correlate with simple formulas. Today we will discuss the Pythagorean Theorem. This is an equation which will give us the length of a third side when the lengths of the other two are inserted.

The formula is C^2 = A^2+B^2. C is the length of the hypotenuse of the triangle, which is the longest side, and A and B are the lengths of the other two sides. In order to use this formula, we would plug in the lengths of the two sides that we know and solve for the third.

Lets go through an example so you can get the hang of how this formula works. Let's say we have a triangle with two smaller sides with the lengths of 3 meters and 4 meters. We would plug these values in to get. C^2=(3)^2+(4)^2. We then have 9+16 which is equal to 25. We still have C^2 and we want C so we would take the square root of both sides to get C=5. Now we know the lengths of all of the sides of the triangle in question.

This theorem is extremely useful, and can be applied across a wide variety of applications such as finding the length of diagonal poles needed to make a tent or finding if a square is truly square (if both diagonals inside the square are equal in length).

So, make up a few measurements and try this formula out for yourself. It is relatively simple so you should get the hang of it quickly. If you have any questions just leave a comment and I will reply promptly.

For more information, check out http://en.wikipedia.org/wiki/Pythagorean_theorem

Lesson 8: Compound Units

In our previous chapter, we discussed the seven basic units which are the building blocks of all the units imaginable. They decribe quantities which can not be broken down any further such as length or time.

In this chapter, we will cover compound units which are comprised of combinations of basic units. These include things such as velocity, acceleration, force, energy and more.

There are way too many compound units to cover in this lesson so we will just go over a few so you can get an understanding and feel for them and you can apply this understanding to other compound units you may encounter in the future.

So lets start off with a simple compound unit, speed. It is represented as distance/time. In the metric system it is typically expressed as meters/second. So we have one unit divided by the other. This can be thought of as x many units of length will be traveled in y many units of time. Typically the numbers are arranged so the units on the bottom are equal to 1 and fractional values can be eliminated to simplify calculations. As an example, lets assume we have a value of 50 m/s. This means 50 meters will be traveled in 1 second.

Now, lets try a more difficult compound unit, force. This is expressed as (mass * length)/time squared. In the meteric system this is usually expressed as (kilogram * meters)/second squared, which is known as a Newton. Don't get scared here, we will jsut apply the same concepts that we used in the previous example. We can break this down into seperate components. Meters/second squared is acceleration, so we know that units of force is just mass * acceleration. So if we had a force of 50 Newtons and an object with a mass of 1 kg, it would recieve an acceleration of 50 meters per second.

Does this make sense? Basically, we are just breaking down the compound units into thier basic unit components to analyze what is really occuring. So take a few minutes and think of a few other compound units and try to break them down to see what they really describe. If you are having trouble, don't worry at all, this is no easy task to perform.

For additional information, check out: http://www.sciencemadesimple.net/units.html
This is a huge list of units which stretches on for pages.
Additionally, check out: http://www.unc.edu/~rowlett/units/
This is a unit dictionary.

Lesson 7: Basic Units

In this lesson we will discuss the seven basic units of the metric system. These units can be combined with each other to define any quantity mankind knows of so far so as velocity which is meters per second or force which is kilogram meters per second squared. These units are used in almost every field such as chemistry, engineering, physics, and mathematics.

1. The first and most obvious basic unit is length. In the metric system, this unit is the meter.
2. Next is mass. This expresses the amount of acceleration an object acquires when subjected to a given force. The standard unit for this quantity is the kilogram. This is equal to 1000 grams.
3. Temperature expresses how hot or cold something is. In the metric system, the Kelvin is used. These units are equal to the Celius scale minus 273.15 degrees. This is due to the fact that the Kelvin scale is absolute, which means that 0 Kelvin is absolute zero and the object is as cold as it can possibly get which means it has absolutely no thermodynamic energy.
4. Electrical current in the metric system is expressed in amps. These units are typically seen on electrical devices along with a given voltage (which is a compound unit and will be covered later).
5. Luminous intensity is expressed by the candela. These units describe how bright a light source is such as a flashlight or spotlight.
6. The amount of matter in an object is expressed by the mol. This quantity is frequently used in chemistry.
7. Last but not least is time, which is expressed in seconds. I won't go into detail here because everyone has had experience with this unit.

With these units, any quantity imaginable can be described. They are extremely necessary in any field of work. So, think of a few objects and think of what units you would need to describe its parameters with.

For further information check out http://en.wikipedia.org/wiki/Metric_units

Lesson 6: Precision

Often, many people don't know that a single number not only descibes a quantity, but also the amount of precision which it is associated with. the number 200 is less precise than the number 200.0 You might be asking yourself why the same two numbers can have different precisions but the answer lies in where the decimal is placed and how many numbers are around it.

Lets first look at the number 200. (period, not a decimal) It is relatively uncertain because there is no decimal place. 200 could have been 249 so the person making the measurement could have just rounded it down or the number could have been 150 and the person making the measurement could have rounded it up. So, 200 is only accurate only to the hundred digit.

200.0 on the other hand is more precise because the decimal after the zero indicates that the number was not rounded in the hundreds digit. However, there could still likely be some rounding going on in this figure. However, due to the decimal place and the zero to the right of it, we know the rounding occured in the tenths place. The number could have been 200.04 or 199.95.

This is a particularly useful aspect to remember about measurements, especially in the modern world. Precision applies to almost every field. It is seen frequently in the news or in arguemental literature. So, when you are given a figure or measurement, take a moment to think about how precise the figure is and how significantly it could have been rounded.

Lesson 5: Scientific Notation

In the technical world, when extremely large or small numbers need to be expressed, a technique called scientific notation is often used to simplify writing these numbers.

In scientific notation, a number is simplified by moving the decimal place around until only one nonzero digit is to the left of it. Then, the number of digits the decimal was moved is compensated by multiplying the new number by some power of ten. This is a confusing concept to understand at first so if you are confused, just stick with it because the examples will help clarify what is going on.

Let's think of the number 2 000 000 000. In scientific notation, this can be expressed as 2.0 * 10^9 (two times ten to the nineth power). So what is happening here, is that the number 2 is being multiplied by 10 to the ninth power which equals 2 000 000 000. Lets take this process step by step so we can see what is happening.

1. We take 2 000 000 000 and move the decimal place over to the left until we have only 1 nonzero digit to the left of the decimal place. So now we have 2.000 000 000 which can be simplified to 2.0
2. We take note that we move the decimal place over 9 digits so then we multiply 2.0 by 10^9. The original number was made smaller so we must make the exponent on the ten larger.
3. Now, we have our final product which is 2.0*10^9 and is exactly equal to 2 000 000 000.

This process can work the other way. We can use this notation to make extremely small numbers easier to write. Lets go through an example to illustrate this. We will use .0000007

1. We will shift the decimal to the right seven places which will give us 7.0
2. We next multiply 7.0 by 10^-7 because we moved the decimal place 7 places to the right. We made the original number bigger so we must make the exponent smaller.
3. This then gives us 7.0*10^-7.

It is important to remember a few things when using this notation. The modified number should always have a decimal in it in order to indicate the amount of precision of the measurement (We will cover this in more detail later), and when we move the decimal to the left, or make the number smaller, the exponent on the ten must get bigger. In contrast, when we move the decimal place to the left, or make the number bigger, the decimal must get smaller.

Lesson 4: Applications of Newton's Laws

So far, through our lessons, we have covered all of Newton's laws. So, in order to get a better understanding of why they are important to us, let us look at a few examples and applications.

First, lets find out how to calculate our mass given our weight. This task is relatively simple when dealing with pounds in the English system because pounds of force is equal to pounds of mass on Earth. However, in the metric system, there is a more striking difference between weight and mass. Think of weight as the force you apply on the ground when you stand on it. Mass on the other hand is a quantity which is consistent with or without the presence of gravity.

So, let's say someone weights 200 Newton's. In order to find mass, we have to use Newton's second law which states, Force = Mass * Acceleration. On Earth, the gravitational acceleration is 9.8 (m/s squared) So, we plug in 200 (Newton's) = Mass * 9.8 (m/s squared) and solve for mass. If you aren't sure how to solve for mass, all we do is divide both sides of the equation by 9.8. So, this particular person's mass is 20.4 kg.

In another example we can find out how much force we have to apply to accelerate an object to some given acceleration. So, for example, we want to accelerate a hockey puck at 10 m/s squared. We will say a hockey puck has a mass of .1 kg. So, we use Newton's second law and plug the values in. Force = (.1 kg) * (10 m/s squared) The force we would have to apply would be 1 Newton.

Now, it is important to remember to keep our units consistent. When inputting values into our equations, we must use meters per second squared, kilograms, and Newtons to maintain simplicity. If you have units that are different, use conversions to convert them. Conversions can be readily found using major search engines.

So, try a few of these on your own. If you aren't sure what the specific measurements are of the particular situation you are analyzing, just ballpark the measurements for practice.

Lesson 3: Newton's Third Law

In continuation with our small series, today we will cover Newton's third law. This is the hardest law to conceptualize but with a bit of explanation, it will become clear.

Newton's third law states that for every force applied to an object, there is an equal force directed in the opposite direction. Contrary to what you might have heard, this law states that when you push something, it pushes back.

Now you might be thinking, how can we ever get something to move, if it pushes back when we push it? The catch is, multiple things get different pushes. To visualize this, the picture below illustrates a few examples.



First, the table exerts and equal force in the opposite direction of gravity to hold the bowling ball up. This is a simple illustration of what Newton's third law states. the negative sign in the equation means the forces oppose one another.

To illustrate this further, with more practicality, a boat towing another boat is illustrated. Each arrow represents the forces being applied along with their opposites. The tug exerts a forward force and an opposing force is seen in the water which is propelled backwards. The large boat is being pulled by the tug but is being opposed by the resistance of the water.

So image you are walking down the street. Your legs are pushing you forward but there is always an opposite force. The ground is actually pushing back (we will cover this in more detail later). This is what keeps your foot still and in this instance is in the form of friction.

This is a tough concept to fully learn and ingest. So just take a few minutes to think about some actions and opposing actions which you encounter every day and hopefully it should start to make more sense. If you are still having trouble, leave me a comment about what you are having trouble with and I will try to clear up the confusion.

This concludes the learning portion of our mini series. In the next few lessons we will apply what we have just learned to some practical, real life instances so you can get a greater understanding of the importance and uses of these concepts.

Lesson 2: Forces and Newton's Second Law

In our first lesson, we discussed Newton's first law and how it states that an object's motion only changes when a force acts upon that object. Today, we will cover Newton's second law.

This law states that the rate at which an object's momentum changes is equal to the force acting on the object. All this really means is that if we have an object and we apply a force to it, there is a direct relationship between the amount of force with which we push with on the object and how fast it ends up going.

Think of it this way. We have a light ball, and we softly push it across a table. It will go slowly across the surface of the table. If we take that light ball and push it extremely hard, the ball will speed across the top of the table. Now we take a heavier ball and push extremely hard. This time, however, the heavier ball has more mass and it rolls across the table slower because we have to push harder to make it go as fast as the light ball.

The length of the arrows in this picture represent approximate quantities. The longer the arrow, the larger the quantity is.



This law basically describes a relationship in terms of numbers. Don't get skittish because this is an extremely easy equation. All Newton's second law says is:

Force = (the mass of the object) multiplied by (the acceleration of the object)

So think of it this way. If we have a 1 kilogram ball and we want to accelerate it by 1 meter per second squared (this is the metric unit for acceleration and means that the ball will go 1 meter per second faster every second), we would have to apply 1 Newton (this is the metric unit of force and is acceleration times mass) of force with our arm.

And with that, we will end our lesson for today. So today, think of a few objects and try to imagine how much for it would take to get them moving in a certain direction.

Lesson 1: Forces and Newton's First Law

Forces can be thought of as a push or a pull. They involve one object acting upon another, like a pool ball hitting another pool ball, or the gravity of the Earth pulling us all down toward the ground. We all have had countless experiences with forces, whether we like it or not, like falling off of a ladder and being kindly welcomed by the pleasing hardness of the ground below us.

Isaac Newton, analyzed forces and motion and describes them in three simple laws. Now if you are getting at all finicky, don't worry, these are way easier to learn than you think.

Today we will start off with the first of three laws and we will cover the next two laws in the next two days and we will look at a few applications after that. With that being said lets begin.

Newton says that if an object is in motion, it will stay in motion, or if an object is not moving, it will stay still unless forces act upon it. At first glance this does not seem quite right because when you kick a ball, it eventually stops, or when a tool is set still on a slanted roof, it might slide off. However, we have to understand that it is extremely hard to find a place where no forces act on an object. On Earth, we have the force of friction that will slow that ball down after it is kicked, or we have the force of gravity which will pull the tool down off of the roof and towards the ground.

Think about it for a while, if we were in space and we were far away from everything, we would just float there. We wouldn't spontaneously start flying around because what would push us? This is the same for something that is in motion. If it is moving, what would be around to stop it? There would be no air resistance, friction, or gravity.

So for today, think about Newton's First law and try to imagine what would happen to the world if we took forces away such as gravity or friction.

With that we will end our first lesson and i will see you tomorrow for lesson 2.

What This Blog is About

In the modern world, technology is constantly growing in importance. Most of the general population is surrounded by ordinary devices which did not exist 50 years ago. Every day, more and more people across the world become owners of a computer, television, cell phone, xbox, or many other useful inventions or innovations. However, these vital advances in technology also bring complication with them. Not many people understand how an electric motor functions which propells thier new hybrid vehicle.

The goal of this blog is to make you, the reader, smarter and more informed about how modern technology functions, through easy, daily, 5 minute lessons which will illustrate the fundamental elements which all technology is based upon. With this knowledge, the reader will be able to understand the rapidly advancing world around them and make more informed decisions pertaining to technology.