Friday, December 18, 2009

Science is easy, but what about Maths?


For many years I have wrestled with the problem of how to get better at Maths, and how to help others do so as well. It isn't easy! I tried all kinds of ways of explaining Maths to people in plain-English. Eventually I became convinced that teaching Maths was actually not possible: Someone either "gets" it or they don't, and nothing you can say or do seems to make any difference.

While that will certainly be the case most of the time, I have recently modified this theory slightly as a result of several chance conversations. One was with a Maths teacher at a local university, the other a student in Social Work who, to my great surprise, happens to love Maths.

In my own life Maths was not a strong suit, initially. I struggled in primary school with the tasks of adding and multiplying. Long division in particular is what I imagined Hell must be like for someone like me who wants to see the Big Picture, and who only worries about details that haven't been worked out before. Dear old Dad finally caved in and bought me a Calculator in about 1975. LED digits. 9-V battery good for about an hour. Fixed decimal point which made the answers off by powers of 10. It was a God-send! A Miracle!

(I now own dozens of calculators, and none of them are completely adequate in all ways. The best calculator for numerical analysis is actually Matlab, a very good and very expensive piece of software. Perhaps my obsession with calculators will be the subject a future post, if enough Readers vote for it!)

University Maths didn't make life any easier for me. I spent an entire year (and a painful one) studying Differential Equations and Linear Algebra. I got C's in both subjects. How is that possible?

I won't blame the teachers, although I won't thank them either. Aside from their impenetrable foreign accents, they presented themselves with an air of utter boredom which I imagine they thought was "professionalism" or even "cool." As if to say, "Whereas you are all morons, I find maths so incredibly easy I can do it in my sleep. I will now demonstrate this fact by pretending to be in a coma while I lecture."

No, students will either learn because of their teachers or in spite of them. I did neither. Why?

The university Maths teacher I mentioned recently gave his theory of how to teach the subject:

"Strip it of all applications and meanings, and deal only with pure notation first. That will get right to the heart of any conceptual difficulty the student may have, without the distraction of trying to interpret 'word problems'."

I immediately recognized the fallacy of this, and realized what the key to learning Maths must be.

My hypothesis was confirmed when I had a chance conversation a few days later with a student in Social Work. I asked whether she found it frustrating to have to take Maths courses which detract from her core interest in getting out there and doing something to make a difference. She said, "No! quite the opposite. I really like Maths, and have always found it easy."

"What do you like about it?"

"I really enjoy order and logic. I like it when things make sense and fit together. It gives me a feeling of satisfaction and control when I can solve a problem and get The Right Answer. Life makes sense when things work out correctly."

Why will some people enjoy Maths and learn it easily, even in spite of poor teaching? Why will otherwise capable students hate Maths and struggle endlessly with it? And most importantly, how do we make Maths easier to learn and to teach?

The human unconscious mind, in order to save us from Information Overload, filters out 99.99...% of all incoming data (sounds, images, stimuli, information), allowing into our conscious awareness only that which it deems relevant. The decision is made based on an individual's unconscious values, beliefs, fears, and desires. Further, memory is also activated in the same way, and we remember only things that unconsciously are important to us or that we care about emotionally. We already have "bins" or structure in the brain for retaining such information. Information far outside our experience is harder to classify and link to previous experience, with the result that there will be few neural connections created to constitute a memory of it.

Therefore in order for a student to have an activated memory and be open to information, it must be information that has emotional meaning to the student, and which relates to something the student already knows well. In the case of that Social Work student and most other "born mathematicians," the emotional meaning of Maths is built-in: the love of order, the satisfaction of being able to solve puzzles, and the sense of "all's right" when they get the one right answer.

Most other students, however, care about different things. Whether it's sports, music, art, books, friends, cars, fashion, money, animals, or Physics, there is always a way to make Maths relevant and something to which a student can and will attach emotional importance. Additionally, the teacher can generate the emotion in the classroom through enthusiasm, a personal story, and showing caring for the students individually. In other words, exactly the way a very good presenter or salesman "sells" any message.

If we want our kids to do better in Maths, (and it is definitely the one subject essential for success in virtually any field), then we should look at changing the way Maths teachers are trained. Or better yet, recruit teachers from the ranks of Salesmen! You don't have to be an expert in N-Dimensional Topology just to teach first-year Algebra, after all. You only need to be an effective communicator and understand the principles of Influence.

How did I eventually get on top of Maths? A decade after my Physics degree, I entered a Master's Degree program for Engineering. I just couldn't get enough of engines, spacecraft, cars, motorcycles, electronics, and gadgets generally. I loved fixing things, building things, and inventing things. When I took a most fascinating course in Control Systems Theory, for example, I needed to know both Differential Equations AND Linear Algebra. Suddenly these were no longer boring, difficult millstones around my neck, but exciting and useful tools that I couldn't get enough of. I was even teaching the other students the finer points of how to use them.

Stripped of all application and meaning, these subjects made no sense to me and I could not produce the excitement and discipline necessary to gain competence. But in the context of something I cared a lot about and had high interest in, they made perfect sense. They are now subjects I am very comfortable with. My engineering professors were absolutely dumbfounded that I had previously earned C's in those subjects.

But is it really such a mystery?


Friday, December 11, 2009

A 14 year-old Discusses Relativity and Science

The most recent Making Sense of Science Newsletter (available at http://www.wallingup.com/newsletters.php) sparked an online discussion with a Year 8 student. From it, I learned that there is not necessarily an age barrier to understanding advanced science topics, and that these challenging topics can supply the interest levels prerequisite to student engagement in the topic.

It also highlights the importance of integrating science with the humanities. This student had been reading the classic Ender's Game science fiction series by Orson Scott Card for his middle school English class (we both give it ***** five stars out of five).

I'd like to share the ensuing discussion with you.

Student: Aliens travelling to earth may have spent 1000's of years on a ship but the theory of reletivity would mean that they would not feel the ravages of time.

John: You are completely correct that aliens in a spacecraft moving near the speed of light would experience less time elapsed than on either their home world or destination planet. To them it might seem only a few years or even weeks. But to get going that fast requires such absurd quantities of energy it seems incredible that they would chose to do so.

So the aliens could survive the trip if they wanted to bad enough and had virtually unlimited energy to waste. But it would still take many hundreds of years of earth time for them to get here. They would have left on their journey at a time long before there were any radio signals to indicate that someone interesting lives here. We have only been sending out radio signals strong enough to be picked up in space for about the last 60 or 70 years, meaning that aliens living 70 light years away, if they are listening, would only now be aware of us. We can't expect to hear back from them for another 70 years, and we certainly can't expect them to drop by for many hundreds of years at least.

Student: Faster-than-light travel might be possible someday. Look at mobile phones! A few years ago people would have said they were impossible, too.

John: One thing to notice is that we did not exactly "discover" mobile phones, we invented them. The natural laws that allow them to operate were discovered more than a hundred years before.
But the computer technology that makes them work was invented step by step over the last 40 years. We did not discover any natural law that said "computers can do this" or "computers cannot do that," so we just kept trying new things.

There is a huge difference between technology and nature. Nature is the tree, and technology is the decorations. Technology must always follow Nature's rules, but Nature does not have to obey or allow technology. We do not discover technology, we invent it. Nature can only be discovered, and never re-invented to suit us. Technology only works if it is allowed by Nature.

Student: Just because we've never seen something doesn't mean it doesn't exist.

John: You are right about that. Don't make that mistake! If a guy says, "Dogs do not exist," because he has never seen one, he will be totally unprepared the first time a dog shows up and bites him on the bum.

We are not saying "there is no faster than light travel" merely because we have never seen it. We say there is no superluminous travel because we have discovered a natural law which says, "all speeds are less than the speed of light." Many experiments have proven that this law is true. They also prove that the opposite of this law is false. All experiments attempting to disprove this law have failed, too. It seems Nature is trying to tell us something, and the message is loud and clear.

We are not exactly in a room with the light turned off, speculating on what might be or might not be in it. We are also not like the guy who has never seen a dog before, jumping to a false conclusion. The light has been turned on. We have discovered that the faster you go the heavier you get until at the speed of light, you weigh infinity. It also takes infinity energy for matter to go that fast. By analogy, we have discovered dogs, and found that all dogs bark and poop. (and have sharp teeth). There is no need to speculate on the existence of dogs, or on the speed of light, because we are in possession of the facts.

Student: You cannot be certain that for example every element in existence has been discovered yet. New things might be discovered at any time.

John: I am particularly impressed with the way you think. Good job. And good on your teachers who cultivated your thinking skills. Your question is an important one: how can we be certain of what hasn't been discovered?

I'd like you to examine, if you would, all the whole numbers between 1 and 118. Are there any whole numbers missing? Are there any that we have not "discovered" yet? Are there any whole numbers in that range that are not known and still need to be invented?

If not, then there are also no new elements waiting to be discovered or invented either. We know of all elements as surely as we know about all the whole numbers from 1 to a million and beyond. Every element in the universe is a whole number of individual protons in a nucleus, with the same number of electrons hovering around it. To work out what possible elements might exist, simply write down all possible whole numbers. There aren't any missing.

This means that often it is specific knowledge of what does exist and how it is put together that enables us to make absolutely certain statements about what else might exist, and also things that cannot exist.

The only way to know the difference between what might yet be discovered and what will definitely never be discovered is to get as much understanding of the laws of Nature as you can. Things that those laws allow are possible at least in theory; things that the laws disallow are never possible no matter how hard we try or how much technology we get.

Student: Yes, but new laws are discovered which prove that the old laws were wrong.

John: Now who told you that? I'm sorry to say this is the first statement that is completely false. This has never happened, and people who say so are simply mistaken.

Newton's laws of physics replaced Aristotle's "laws". But those so-called laws were actually wrong to begin with, as any simple experiment could show. They were not really laws, but actually philosophical beliefs that were never tested in practice before they were written down. Galileo proved them to be wrong in his experiments. Finally, Newton worked out the simple laws of motion, forces, speed, mass and distance.

Einstein's laws of Relativity are sometimes said to prove Newton wrong, but the truth is that Relativity proves Newton was exactly right for all possible earthly speeds we encounter in everyday life. It is only speeds above 20 or 30 million meters per second that more information is needed.

Quantum mechanics is said to prove Newton was wrong, too. This deals with objects smaller than atoms, and it says they don't behave according to Newton's laws. But here too, Newton is proved right. Quantum mechanics tells us that large numbers of particles in a bunch together behave exactly as Newton would predict. Things even as tiny as a grain of sand obey Newton's laws perfectly, for all practical purposes. (How many atoms are in a grain of sand? See an older post in this blog.)

So a law that is proven experimentally does not stop being true, even when more information about totally different situations is uncovered.

Student: So the best way to invent stuff is to learn exactly about the laws of science so you can take advantage of them?

John: Good for you! Now you're on the fast-track! People who don't do what you suggest get bogged down forever basically re-proving the laws of Nature that are already known, and never invent anything useful. Do what Isaac Newton said, and Stand on the Shoulders of Giants to see farther than you would on your own legs. And Happy Newton's Birthday, 25 December!

Watch out for this kid. He's only 14 now, but he's going to make a difference.

Tuesday, November 3, 2009

What are atoms made of?

Everything you will ever encounter in your entire life, everything you will ever eat, touch, hold, see, feel, hear, taste or smell, every part of the earth you stand on, the air you breathe, the house you live in, your entire body, the clothes you wear, even your wristwatch and jewelery, everything you can see out in space, the stars, planets, comets, galaxies, the telescope you use to view them, the sofa you sit on, the TV you watch while sitting on the sofa, the remote control you clutch in your hand (if you're a guy), and the cheezypoof crumbs that adorn your shirt ...

All these things and more are composed of just three kinds of building blocks. Combinations of these three simple bits comprise everything of any consequence in the physical universe. They are The Electron, The Proton, and The Neutron.

The Electron. It carries a negative electric charge, meaning it repels other electrons and is attracted to positive charges. It is very lightweight. Mysteriously, every electron has exactly the same mass and charge as every other electron. As far as the best instruments are able to detect, the electron has no size, but is a single geometric point.

The Proton. A massive particle with a positive electric charge, exactly equal and opposite to that of an electron. Protons have a diameter of about a trillionth of a millimeter. They repel other protons and attract electrons. They are also slightly sticky. Although they repel each other, if you get them close enough, they will stick together.

The Neutron. This weighs about the same as a proton and is about the same size. It is also sticky, like a proton. But it has no electrical charge and is therefore very hard to control, to hold, to detect, or do much of anything with.

When a bunch of protons are mashed together, they sometimes stick and form a ball called a nucleus. They find it easier to do this when some neutrons are included to add more "stick" and help them overcome their mutual electrical repulsion.

When a nucleus forms, it has a strong positive charge equal to the number of protons. Eventually, an exactly equal number of electrons gets involved because of the strong electrical attraction. Then a funny thing happens: the electrons are unable to get closer than a certain distance to the proton/neutron cluster and they end up hovering around in a kind of layered, structured cloud. That's what we call an atom.

How big is the nucleus? If an atom were the size of a sports stadium, the nucleus would be about the size of a marble laying in the grass at center field. Except there would be no grass. Electrons would be the spectators sitting in the stands, except there would be no stands, just electrons.

Carbon, for example, is the kind of atom you get when any 6 protons form a ball. Some neutrons are needed to help them hang together. Zero to two neutrons isn't enough, and results in an unstable ball that almost instantly disintegrates due to the proton's mutual repulsion. Three to five neutrons is almost enough and results in a nucleus that survives for a few hundred milliseconds to a few minutes. The more neutrons, the more stable it is.

With 6 or 7 neutrons, the 6-proton neucleus (Carbon) is stable. 98.9% of Carbon atoms have 6 neutrons, while 1.1% have 7. We call these "isotopes" "Carbon-12" and "Carbon-13."

Carbon-14 is famous for its ability to indicate the age of things that contain carbon. In the atmosphere, carbon is exposed to radiation which "activates" some small percentage of it. The result is Carbon-14 which is unstable but which decays very slowly. About half disappears every 5730 years. That rate of decay can be used as a kind of clock to determine how long a carbon sample has been "out of action" as it were.

Electrons, Protons and Neutrons are all that are needed to create every element on the periodic table, and therefore every chemical compound, and therefore every object or substance you will ever encounter in this physical universe. It is true that protons and neutrons are themselves composed of smaller pieces, but they play no significant role in everyday life.

Only three things to keep track of? Anyone can cope with that. And you thought Science was going to be hard.

Sunday, October 18, 2009

How Small is an Atom?


A textbook or encyclopedia will tell you that a typical atom is about 0.0000001 of a millimeter in diameter. Now, how are we supposed to picture that? That information may be helpful for calculating how big a carton you'll need for mailing a given number of atoms to someone, but then again, maybe not. It certainly doesn't help the typical person understand what all the fuss is about.

Here's a way you can visuallize the size of an atom, and the vast number of atoms that comprise the everyday objects in your world. For this experiment, I'd like you to get a pin. Find an ordinary sewing pin, now, before reading any further.

Got one? Good. Look at the head of the pin closely. If you have one, use a magnifying glass or even a microscope to look long and closely at the head of the pin. Just stare at it for a while.

Now close your eyes and imagine yourself shrinking down, almost vanishing, descending down onto on the head of the pin. You have shrunk down so small that the head of the pin is a vast desert on which you are standing, the edges of which you cannot see. You begin walking in one direction.

You continue walking on the head of the pin for many days before coming within sight of the edge. How far have you walked? 50 miles? 100 miles?

For the first time, you look down at the surface you have been walking on. It's fairly smooth, with an occasional ditch to stride over and variations up and down. You recognize this as the results of polishing when the pin was manufactured. You kneel down for a closer look at this shimmering surface and notice that it seems to be made up of small marbles packed closely together, and they are all vibrating slightly. Now you are seeing individual atoms. There are mostly iron, but also nickel, copper, and several other species, distinguishable by their differing sizes.

Open your eyes and look again at the head of the pin. You will now be able to visuallize how small atoms are and how impossibly many there are just on the head of that pin.

Now I'd like you to picture yourself on the beach. Next time you go to the beach, remember this and go through these steps. Stand on the beach and look up and down the shoreline. Picture in your mind how deep the sand might be. Deeper than a house is tall? How much sand?

Reach down and pick up a handful of sand. How many grains of sand do you see? Could you even begin to count the number of grains of sand you are holding in that one handful?

Allow most of the sand to fall through your fingers. Inevitably, a few grains remain clinging to your skin. Look closely at your hands, and try to pick out one single grain of sand.

While looking at that one grain of sand, say the following words: "There are possibly more atoms within that single grain of sand than there are grains of sand on this entire beach."

It is no wonder then that the existence of atoms was completely unknown for so long, and then, debated for so long. By about the start of the 20th century, the indirect evidence of atoms from observations made over the previous few hundred years had finally won over most people to the concept and existence of atoms. Now, we have technology that can directly image the atoms on the surface of a grain of sand or on the head of a pin.

Of course, Mankind has gone far beyond that and has probed the very inner workings of individual atoms and the parts they are made of. That will be the subject of a future post.

What Exactly is Heat?

Energy is nothing more mysterious than motion. Things that are moving have energy, which is another way of saying that they are moving.

Suppose the countless atoms that make up an object are all moving with tiny, random motions in all directions at once. It's matter, and it's moving. So it's also energy. When it's in little pieces comprising a large object, we call it Heat.

Scientists have technical words they need to use such as "internal thermal energy," but we know that it's really just lots of little motions of lots of little objects in many directions at once. The atoms may be vibrating, spinning, or actually wandering about (if it's a liquid or a gas). It's not really different to the energy of a car whizzing down the street, just a lot smaller and a little trickier to keep track of. Remember, physics is mostly about being a good energy accountant.

Rather than a speedometer, we use a thermometer to keep track of heat energy. The temperature tells us the average speed of the many moving bits. The higher the temperature, the higher the average speed and therefore the more energy is in there. Trust me, it's easier that trying to put a little speedometer on each individual atom.

The temperature is higher when there's more energy. What if all the atoms were to stop at the same time? What would the temperature be then? Answer: -273 C. That's Zero on the absolute temperature scale, or 0 Kelvin.

I have a 1 kg block of ice in front of me that is at a temperature of negative 10 C, or ten below zero. If I add some heat to it, the temperature will go up. If I add 2 kiloJoules of energy (or heat) to it, the temperature will go up by 1 degree. If I add 20 kJ, the temperature goes up by 10 degrees. It's easy to do, but hard to keep track of. How do I add heat? By doing nothing.

Heat always spreads out. It does whatever it can to get away from high temperatures and move to lower temperatures. Just by leaving the block of ice sitting out, heat from the surrounding 20 C room moves towards the -10 C ice in whatever way it can. In this case, mostly through air currents.

Air next to the ice block gets cold. Cold air is heavier, and starts to sink down. Warm air then takes its place next to the ice, and the whole process repeats automatically. As the ice absorbs heat from the air in the room, the ice warms up. One result of that is that the rate of warming slows down. The other result is that the ice eventually starts to melt.

Ice melts at a temperature of 0 C. As we add more heat, more ice melts. But the temperature does not increase until all the ice is melted! Why not?

Water molecules in ice are stuck together and cannot move around. Water molecules automatically stick together when they are not moving very fast, in other words, when the temperature of the water is low (below 0 C, to be exact). If we want them to be unstuck and form a flowing liquid, then we have to give all the water molecules enough motion (meaning energy or heat) to move clear of each other. As we add heat, the temperature stays at 0 C until all the ice is melted. When we have added 335 kJ of heat, then the entire 1 kg block of ice will have melted. Scientists call that "The Latent Heat of Fusion," but we know it's just giving sufficient motion to the molecules to remain free. It's the same energy: motion.

I now no longer have a block of ice on my desk. I now have a litre of water in a pan which I had wisely placed under the ice. I knew what was going to happen, see. The water's temperature is still 0 C, but heat continues to flow towards it from the warmer surroundings. Every time the temperature increases by 1 degree, I know that another 4.2 kJ of heat has gone into the liquid water. Well, that's interesting! It takes more than twice as much energy to warm water as it does to warm ice! Why?

There are more ways for free water molecules to move. Up, down, left, right, forwards, backwards, and spinning in all directions. Previously, they could only wiggle a bit this way and that within the ice crystal structure. Each kind of motion takes a bit of energy to produce. Water molecules have to be doing all of them in order to make the temperature what it is. Therefore, raising the temperature of water requires more heat than it does for ice. Is that why the ice cubes in your drink never cause the entire drink to freeze? It's always the ice that turns to water, and not the other way 'round. How much ice would you have to put in a glass of water to make the entire glass freeze? Come on, accountants, get out your pencil and a calculator. It's not hard.

Eventually, when roughly 84 kJ of heat has entered the water, its temperature will be the same as the surroundings, and the flow of heat will trickle away to a stop. This happens increasingly gradually. Where the trip from 0 to 5 C may take only a few minutes, moving from 15 to 20 C may take hours.

One thing to remember about heat: our hands are not very good thermometers. They tell us when heat is moving into our hand (when we pick up something hot) or out of our hands (when we plunge them into ice water), but try picking up a handful of snow with a gloved hand. The insulation slows the heat flow out of our hand and we do not perceive the temperature as it actually is.

You already know that walking on carpet with bare feet does not feel as "cold" as walking on cement or tiles. But the carpet is exactly the same temperature as the tiles! Just something to think about.

Heat may be endlessly interesting, but never a mystery.





Wednesday, October 14, 2009

The Many Forms of Energy

I said last time that energy is nothing mysterious, only matter in motion. I also said there is a wide variety of ways that different kinds of matter can be in different kinds of motion. Here's some of them.

A single particle of mass moving in a straight line. Kinetic energy.

A big solid bunch of mass moving in a straight line. Also kinetic energy.

A solid bunch of mass rotating. Rotational kinetic energy.

A block of mass swinging from a rope. In this case kinetic energy is alternately taken up and released by gravity as the mass swings back and forth. As a system, the pendulum can be regarded as having vibrational energy.

A block of mass bouncing on a spring. Also regarded as a system. Kinetic energy is alternately taken up and released by the electrostatic forces between the atoms in the spring.

A block of mass ringing like a bell. This vibrational energy is very minute, but is basically the same as a bunch of little masses on little springs. A guitar string is a simple example of this.

A block of mass with all its atoms jiggling randomly. This is always happening anyway, but the hotter something is, the more vigorously it happens. Temperature is a direct measure of the amount of energy in the form of heat that something has.

In the real world, a block of matter could have all of these at the same time.

If we roll a ball along a level field, it doesn't keep going. Friction, we call it. But what's really going on?

The one thing to know about energy is that, while it can never be created from nothing and it can never disappear, it likes to spread out. It is always trying to disperse itself. Imagine you had a box of atoms that were all perfectly still, and you threw another atom in very hard. Now you have a box of perfectly still atoms with one very energetic, speedy atom. Will things stay that way for long? Of course not. As time goes on the speedy atom will share its kinetic energy with all the others through numerous collisions. Eventually, the energy will be evenly and randomly shared among all the atoms in the box.

In a similar manner, kinetic energy of large masses gets spread out by being shared with smaller objects, air molecules, the atoms of things it rubs against, or its own constituent atoms. For example, drop a bag of sand on the ground. Does it bounce? Where did the kinetic energy go that it had just prior to hitting? All the grains of sand inside it rubbed against each other and each of them became slightly hotter. Given half a chance, kinetic energy eventually turns into heat energy, because heat energy is more spread out.

Heat energy is still a form of energy, and as such tries to spread out even further. It's the one thing to know about energy: it is always trying to spread itself out. The result is that heat always flows in the direction of hot to cool.

Heat is one of the most fascinating forms of energy and one of the trickiest to understand. If you keep in mind the one thing to know about energy, you won't go wrong. Heat is made from more concentrated forms of energy and is always spreading itself out.

Next time, more about heat and how it relates to temperature.

Tuesday, October 13, 2009

Why do I say Science is Easy?

Science is not a collection of facts, equations and definitions. It is not. It may seem that way based on your (and my) experience in the classroom.

Science actually is a method for finding things out. It's as simple as making a statement of presumed fact, then testing that statement until it is proven false. Statements that are not disproven are added to, built upon, and expanded. In practical terms, such statements that are verified by experiment and observation become "facts." Extremely reliable facts.

Gaining an understanding of the physical world means discovering these facts for ourselves and convincing ourselves of their validity. As professionals, we know that there is no way to actually teach somebody something. The best we can hope for is to lead someone to a place where they can discover it for themselves. Only then does the change in thinking and the change in behavior occur which is known as "learning."

Here's the bit I'm prepared now to prove to you: Physics is no more difficult than accounting or bookkeeping. In bookkeeping one must be aware of the various ways money can come in and go out of an organization. Also, there are various ways money can become stuck or stored within an organization, such as in bank accounts, assets and so on. There are also various ways for negative amounts to become stored, such as liabilities, debts, entitlements, and so on. Once the bookkeeper is aware of these, it's a simple matter of adding and subtracting the various amounts to find out where we're at.

Physics is primarily the study of energy, and is no more complicated than bookkeeping. There are various ways for energy to enter and leave a system, or become trapped and stored within a system. Once we can picture this in our minds, it's a simple matter of adding and subtracting the debits, credits, the assets and the liabilities to see where we're at.

The universe has proven to us time after time that energy is never created or destroyed; only transformed from one form to another. But what exactly is this mysterious substance? Not mysterious at all, actually.

Energy is simply this: matter in motion. Anytime there is matter and it is moving, that's energy. As many different forms of matter and as many different kinds of motion there are, that's how many different forms energy can take. But it is nearly always convertible from one form to any other form, following this one rule. The transformation must occur through an actual, testable and observable "mechanism" or logical process.

Energy also responds to the three basic forces of nature: Electromagnetism, Gravity, and Nucleic "sticky" force. I'll explain that last one in a subsequent post.

How this works is fairly simple, too. Suppose an object moves away from the earth in spite of Gravity encouraging it otherwise. When that happens, energy is claimed and becomes locked up or stored. Throw something into the air and it slows until it stops completely, even if only briefly. Then when something moves where Gravity is encouraging it to, energy is liberated. A falling object picks up speed as it falls. The influence of electrical and magnetic forces operates in a similar manner.

All we have to know about energy is that it only transforms, it never vanishes.

Next: An overview of some of the kinds of energy we encounter.