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SCIENTIFIC'S AMERICAN INSTANT EGGHEAD
Fusion and Fission are cousins
the ying and yang of nuclear physics
Both turn matter into energy using the most famous equation in all of science
E = mc2
The equation tells us that matter can turn into energy
and when it does, it gets multiplied by the speed of light squared
a very big number
both fusion and fission convert a little bit of matter into a lot of energy
so how do they differ?
Fission means to come apart
Imagine a tablet of alka-seltzer dissolving in a glass of water
Fusion happens when atoms come together
when two become one
In both cases, we end up with a little less mass than what we started with
that missing mass, multiplies by c squared to become E
In Fission, the fission happens on it own
Radioactive elements such as uranium and plutonium split apart
without any proding from us
This makes fission relatively easy to control
It's why it's used in all existing nuclear power plants
Unfortunately, the stuff that uranium and plutonium fisses into is toxic and radioactive,
creating the by-product that we call nuclear waste
Fusion is cleaner and more powerful, but it's much more difficult to achieve
It requires slamming hydrogens ions together with such incredible violence
that they overcome the repulsive forces pushing them apart
As a result, they fuse into helium
Today, fusion only happens in places with incredible temperatures and pressures, like the center of the sun
or a hydrogen bomb
[wrooom]
But scientists are trying to squeeze hydrogen atoms together with powerful magnetic fields or laser beams
allowing us to control the fusion reaction and extract its energy
Yet all the squeezing takes a lot of energy, much more than we've been able to get out of the process
Because of this, the first fussion powered plants are decades, if not centuries away
Until then, fission has the only mc squared we'll be able to use for energy
For Scientific AmericanĀ“s Instant Egghead, I'm Michael Moyer