What does E=mc2 mean?

In this video, I explain what Einstein's equation E=mc^2 means and why this discovery became one of the most famous equations in the world.

Transcript:
E=mc^2 is one of the most famous equations in the world, but what does it actually mean?

This equation tells us that energy and mass are the same thing. They are related to each other by a constant and that constant happens to be the speed of light squared. Light travels at 300 million metres per second. If we take one kilogram of mass we get 9 times 10 to the 16 joules of energy out, which is 9 with sixteen zeros after it. That's an incredibly huge amount of energy. In fact it's enough energy to power the United Kingdom for one whole year. It was this discovery that gave birth to the quest for nuclear energy.

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Credits:
Written, animated and produced by Emma Osborne
Ident by Brett Josef
Start up funding from 'I'm a scientist get me out of here'
Scientific accuracy double checked by Prof. Nils Andersson

[caffeecup]

E=mc2
E - Energy
M:mass
C2 : constant squared

[zokaW]

If i had you as my teacher i would probably still be in school

[lassoatrain]

I have a question but first you need to do this to understand the question. Imagine you have two lines both 4 inches long.
Take the first line and make a square.The square would now have 4 sides 1 inch long .now calculate the area 1x1 = 1 square inch. Now take the second line and make a circle. The circle would have the same circumference as that of the squares perimeter, 4 inches . Calculate the area of the circle with a 4 inch circumference and you get 1.273 . But the square is only 1 square inch.
The reason is the square and a circle are different and no matter what you do you can not make them the same .You can't square a circle. Once you realize this and get over your world being turned inside out you can see things in a much clearer way.it gives you something you can associate things too. Like you can't make someone someone they are not. You can't square a circle. And not only that but you can't treat a circle as a square or visa versa you can't measure a circle like a square because they are different.
Ok now here's the problem. The constant speed of light is derived from light .Light radiates in all directions at the same time . It does not matter if you block all the light so that only one photon escapes it just means that after 1 second the photon is a point on a radius of 186, 000 miles calculate the area. That area is what the circle of light would fill in one second and is equal too the constant speed of light for 1 second. Now when Einstein squares the speed of light he multiplied 186, 000 by its self 186, 000x 186, 000 and when he did that it now describes an area .the area of this square is different then what the area of light would be because its a square and is different then the circle. you can not treat it as a square. Do you realize you can not make a velocity equal to a square. At any constant velocity because after one unit of time it may touch the four sides but it would not fill the corners. You can not square a circle in a measure of a unit of time. The square of the speed of light is not equal to one second of time at the speed of light. You can not fill a square of any size at any velocity. The square is not possible when dealing with the circle.make a picture with a circle aftet 1 second of the speed of light and it's perfect it fills the circle perfectf.now try the same with a square. It's wrong. Every single thing about it is nonsense. Your thoughts appreciated.

[soniat]

For me clearest explanation so far without doing too much. Though it's a bit incomplete...

[exaucemayunga]

If they can power the a whole country with 1kg why don't they do it?

[gabrielspataru]

Im in 6th grade this is my first year of physics and i cant even wait to discover the universe.Einstein and Copernicus were always my Idols.I learned about Speed, Density, Force so much intresting things

[maxxc]

they always just say "speed of light squared" without any explanation to what that means. for once I would like to hear an explanation to that

[Splaturne]

It means...

*Mine Craft 2*
ITS GOING TO RELEASE!!!

[keithwolter]

Beautifully straightforward and simple. Too many videos gloss over the actual reasoning behind the equation and jump right into its applications.

[christinehales]

Gets the point across without making it really complicated.

[murrayelliott]

Thankyou for an easy explanation of the equation

[petenutsford]

The way I understood the equation was this: E=MC2 refers to ENERGY=MASSxSPEED OF LIGHT SQUARED. And this means that if the mass is moving (say a person running), that person increases in weight (mass) as they go faster. Einstein proposed that it is impossible for a person to travel at the speed of light, because the faster you go - the more you weigh - ever increasing. Where's the extra weight coming from? - that is gained by the your mass pushing the molecules in front of you then acting against you causing the extra weight. That is how I understood it anyway. anybody confirm?. Thx.

[spaceadventurerb]

A newbie question if I may. Where did 9 to the power of 16 come from?

[temmorijken]

I need someone's help. Everywhere I read about this, it seems to indicate that, for example, hot water is heavier than cold water. However if mass is a form of energy then wouldn't it be so that when you add energy to water, it gets either heavier or hotter (or a combination between those two) but not both. This would seem like you get twice the energy.

An actual problem in my book where exactly the amount of energy was added to a cup of 100mL water to warm it up from 0 to 80 degrees. They then asked how much heavier the water had become after it got up to 80 degrees. I thought it was a trick question since all the energy would've already been converted into warmth but according to the answer ALSO mass was added.

Can someone explain this?

[frankdimeglio]

ON THE ABSOLUTE PHYSICAL EQUIVALENCY AND BALANCING OF E=MC2 AND F=MA:

It is a very great truth in physics that the ability of thought to DESCRIBE OR reconfigure sensory experience is ULTIMATELY dependent upon the extent to which THOUGHT IS SIMILAR TO sensory experience, AS E=mc2 IS F=ma; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. (THOUGHTS ARE INVISIBLE.) INDEED, E=mc2 IS DIRECTLY and fundamentally derived from F=ma; AS time dilation proves that electromagnetism/ENERGY IS GRAVITY. Therefore, ultimately and truly, time is possible/potential AND actual IN BALANCE; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. In fact, INSTANTANEITY is FUNDAMENTAL to the FULL and proper understanding of physics/physical experience; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. THE stars AND PLANETS are POINTS in the night sky. A PHOTON may be placed at the center of what is THE SUN (as A POINT, of course), AS the reduction of SPACE is offset by (or BALANCED with) the speed of light; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. E=mc2 IS F=ma. GREAT !!! BALANCE AND completeness go hand in hand. It all CLEARLY makes perfect sense. (Very importantly, outer "space" involves full inertia; AND it is fully invisible AND black.) The INTEGRATED EXTENSIVENESS of THOUGHT (AND description) is improved in the truly superior mind. Gravity IS ELECTROMAGNETISM/ENERGY.

By Frank DiMeglio

[mogheen]

Why do they use metres instead of miles or km?

[edstud]

where does joules come from in the equation? mass is kg and the speed of light is meters per second.

[BAFREMAUXSOORMALLY]

According to scientific folklore, Albert Einstein formulated the equation E = mc2 in 1905.
The truth is that in 1900 Henri Poincaré came up with E = mc2, but did not connect E with
the mass of any real body. In 1904-1905, Fritz Hasenöhrl's works were followed by the
obscure patent clerk Albert Einstein who in 1905 was the first to propose the correct
relationship, E = mc2, but he didn’t actually prove it. (Tony Rothman on August 24, 2015)

[zakirhussain-jsku]

During conversion of Mass to energy, system losses mass & gains Motion. Mass, motion & energy are equivalent & cmutually convertible.

[jameconradi]

Why is c2 if nothing can travel faster than light