Saturday, November 22, 2008

E = mc2 explained

I've been browsing the internet and I happened to see that the famous equation E = mc2 had been with us for over a century. This equation was derived from Albert Einstein's Special Theory of Relativity.

When I was a kid, whenever I was asked what I want to be when I grow up, my answer is not the usual answer kids of my age would say. No, I don't want to be a teacher, nor a doctor, nor a flight stewardess. I want to be a scientist. I had excelled all in my science subjects when I was in elementary & high school and when I was about to go to college I told my father that I would like to take Chemical Engineering or if not possible, BS Chemistry would do. But my father is not the supportive type of a father. He just said "Are you nuts?? Take accounting! It would be easier for you to find a job if your an accountant!" So there I go. Perhaps, if I would be given a chance to go back in time. (I bet, a time machine is in the making at this time) I would insist.

Going back to the equation, let me explain, in my understanding, what the equation means.

E = mc2, means that the energy (E) is equals to the mass (m) multiplied to the speed of light (c) squared.

Lets do it term by term first.

energy It is defined as the ability to do work. Basically, the types of energy are Kinetic (the energy in motion), and the Potential (the stored energy). For example, an old train that used steam engine for power. The potential energy of the coals (chemical energy) were turned to heat (thermal energy) by burning the coals and boiling the water, then this thermal energy was turned to energy in motion (kinetic) by forcing the steams to push the pistons that will turn the wheel and making the train move.

The unit of measurement for energy from whatever source is joule. In food, a calorie contains around 4.2 joules. So a chocolate containing 100 calories is also containing 420 joules of energy. Lets go to an incandescent light. The watt which is the rate of energy consumption is equivalent to 1 joule. So if you have a 100 watt light bulb, it is using energy of 100 joules. Then lets go back to our 100 calorie chocolate, if we turn its chemical energy to electrical energy, it is enough to light a room for 4.2 seconds. Awesome isn't it.

mass - it is the measure of a body's inertia and is measured by kilograms. Mass is always mistaken as weight. Weight is the amount of gravitational pull felt by an object and is measured in newtons. Example, an astronaut has the same mass here on earth and on the moon, but weighing him will produce different results because the gravitational pull on the moon is different from the gravitational pull of the earth.

speed of light- there is nothing faster than a speed of light which travels to 186,300 miles per second or 300,000 kilometers per second. This is difficult to believe but think of the mobile phones that we used now. When you speak through your phone your voice is converted into electromagnetic signal that beams through the speed of light via a satellite to the mobile unit you are calling. For example, you are calling a friend thousand of miles away from you, imagine just how fast your voice travels through the speed of light.

But why squared? It has to do with the nature of energy. When something is moving four times as fast as something else, it doesn't have four times the energy but rather 16 times the energy—in other words, that figure is squared. So the speed of light squared is the conversion factor that decides just how much energy lies captured within any matter. And because the speed of light squared is a huge number—448,900,000,000,000,000 in units of mph—the amount of energy bound up into even the smallest mass is truly mind-boggling

So now, what does the equation means?

This equation tells us that energy is equals to mass, as mass is equals to energy and how much energy is contained in a given mass and the other way around. Mass & energy are of the same thing. From Einstein's Law of Conservations of Energy & Mass, lets take for example burning a wood, if we gather all together the ashes, the smoke and the vapors we produced in the process of burning and weigh them all up, we will find out that the mass is equal to the mass of the wood before it was burned up. From the burning wood on the other hand, a chemical energy was released, and from this chemical energy, heat energy was formed. No other energy was created, it only changed from one energy to another energy. In other words, the total energy just like mass remained the same.

I know there is so much to understand. Yet Science still amazes me. Is it really too late for me to go on with what my heart desires?


Anonymous said...

No, it's never to late to do what your heart desires. Thank you so much for helping me to understand that formula. I am really struggling in my astronomy class to the point where my 13 yr old son has been helpin me. Your blog was the best explanation I have found. I hope you go back and do what you love if you haven't already. Thanks and Good luck.

Anonymous said...

dude this guy is TOO smart

cori said...

this guy is TOO smart!

Anonymous said...

very good..this is very useful

jad said...

best explanation ever....if nothing else i believe you would make a perfect science teacher

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