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Current time:0:00Total duration:2:59

So I was watching my brother play this video
game. And he used a cheat code that let his character
do a “walk-through-walls” hack. He pushed himself against a barrier in the
game, hit some buttons and boom! His character appeared on the other side. Imagine if something could walk through walls
in real life. And it turns out, you can. At a quantum level. We’re on a scale of the stuff that make
up atoms. Strange things happen at the quantum level. For one thing, all subatomic particles? They’ve got split personalities. One personality is a wave and the other is
a particle, but they’re still one being. When you wanna know where they are, they seem
like a particle. When you wanna know what they’re doing,
they behave like waves. But you can’t ask both personalities at
the same time. Basically, they’ve got some serious commitment
issues. And that means that we can only guess where
they might be. Imagine an electron has two dice, six sides
each. What the electron rolls is where it will sit
along this line. Our electron can’t commit to a position
until the dice are rolled. Remember? Serious commitment issues. So, as our electron is shaking the dice, it’s
everywhere at once. Something -- like us trying to measure its
position -- has to force the electron to let go of the dice and pick a spot. Of all combinations, getting a 7 is more likely
than 2 or a 12. In reality, though, the electron can be in
more than just 10 spots since there are MANY more combinations than just two dice. Now, we can picture subatomic particles as
this: a probability wave. This wave will tell us the odds of finding
the particle at that location. Say this is our electron’s probability wave. The peaks of the wave is where we’re most
likely to find the electron. And in the valleys, it’s less likely we
find it there. Let’s say the electron wave is heading towards
a barrier. As it hits the barrier, the wave bounces off. But lemme tell you something about waves. They aren’t perfect. For example, a beam of light doesn’t perfectly
reflect off of a surface, a small fraction of light can get through. Waves won’t bounce off perfectly. So neither will the electron wave. Sometimes, the wave can slip through the barrier. When the wave is in the barrier, the chances
of finding an electron there goes down by a LOT. BUT IF the barrier is thin enough, the wave
can reach the other side before it dies off. So, what does that mean? Remember, the wave tells us how likely it
is to find the electron there! This means there’s a small chance we can
find our electron on the other side of the barrier. Or in there, too. Once it’s on the other side, we can say
the electron “tunneled through” the barrier. This is “quantum tunneling” and that’s
how subatomic particles can “walk through walls.” Okay, so little elementary particles can walk
through walls, but I can’t because my body is made of more than a quadrillion of these
quantum objects and the odds of all of them tunneling through the wall is practically
impossible. So why does quantum tunneling even matter? It’s the reason we’re alive. Quantum tunneling allows nuclear fusion. Sounds familiar? That’s how the sun releases huge amounts
of energy, that makes life on our planet possible. So how can you quantum tunnel at home? You already are! It’s one of the ways our DNA mutates, among
other roles that quantum physics plays in biology. Quantum physics makes it seem like the world
is playing cheat codes on us, but it isn’t. It’s how the universe works. Maybe the quantum world is telling us that,
when faced with an obstacle, there’s a small chance we can defy expectations and breach
barriers. Thanks for watching.