Albert Einstein’s most commonly known contribution to science, E=mc2, relates energy to mass. The energy conservation law preached to high school physics students states that energy can neither be created nor destroyed. As a result, mass can be seen as a “type” of energy (but acts more like a massive store of energy). The conversion of mass into energy is how the Sun produces energy through thermonuclear fusion.
How much energy does mass store exactly? Einstein’s equation gives us the answer. The amount of energy stored in the mass of an object is equal to the mass times the speed of light squared. The speed of light is about 300,000,000 m/s (as investigated thoroughly in my first blog post), which is a very big number! The square of the speed of light is even bigger: 90,000,000,000,000,000 m2/s2. If you multiply this number by even a very small mass, you will still get massive amounts of energy.
You decide you want to see for yourself whether Einstein was right about the amount of energy that mass holds. You start small…you decide to use the mass of an electron – 9.12×10-31 kg. You put that electron into your mass converter (which unfortunately does not exist in real life yet) and it gives you a disappointing 8.2×10-14 joules of energy. Which means nothing actually happened.
You’re frustrated, so you decide to use something bigger. You don’t want to blow yourself up, so you decide to test a single human cell. You pop that cell (about 1×10-12 kg) into your converter, and out comes 90,000 J of energy. 90,000 J is not a lot of energy. A 100W lightbulb uses 100 joules of energy per second, so leaving that lightbulb on for 900 seconds (15 minutes, or about half the length of your favorite TV show) would consume the same amount of power.
You now decide to use objects you can actually see without the help of a microscope. You look around outside, and you throw a grain of sand (mass 3.5×10-10 kg) into the converter. The energy you receive from this grain of sand gives you enough energy to power your 100W lightbulb for over 3 days (31,500,000 J of energy).
The thrill of these explosions causes you to keep finding bigger objects. You snatch a mosquito flying around your house and discover that its mass (2.5×10-6 kg) gives you 2.25×1011 J. This amount of energy, if released all at once, is the equivalent to an explosion of 50 tons of TNT. Alternatively, if pumped into our 100W lightbulb, would light it for over 71 years.
You discover your invincibility after surviving the release of energy from the mosquito, and you go decide to really invest in this project. You put a dollar bill into the converter. The dollar bill is 1×10-3 kg (1 gram) and is worth much more than a dollar if converted into energy. The energy released in this conversion is 9×1013 J, which is more than the energy released in the atomic bomb that was dropped over Nagasaki. Instead of destruction however, this energy can be used to power the 100W lightbulb for 28538 years.
At this point, you are throwing everything in the converter. Selling the energy you are producing is worth more than what the object is worth.You convert your 2 kg laptop into 1.8×1017 J of energy which is about 50 megatons of TNT, or equal to the energy released by the Tsar Bomba, the largest nuclear weapon ever detonated. Using this energy, the lightbulb stays lit for over 57 million years.
Somehow, after surviving blasts of energy equal to the most formidable nuclear weapon ever tested, you drag your piano into the converter. This 400 kg piano yields 3.6×1019 J of energy, enough energy to power the electricity needs of the United States for over two years.
Turns out, the rest of the world isn’t invincible. Instead of patenting your converter and receiving a Nobel Prize, you obliterated everything. Except your 100W lightbulb. The piano’s energy will allow it to shine on for another 1.1 billion years.
Sources: Approximate masses of objects
Approximate energy equivalents
TNT comparisons
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