0:00 Did you know that everything you can see and touch—your phone, the air, the stars—is made from just a handful of tiny, fundamental ingredients?0:10 Wait, EVERYTHING?0:11 That seems...0:12 impossible.0:12 Last week we talked about how most of the universe is dark matter and dark energy, stuff we can’t see at all!0:20 Exactly!0:21 That's the perfect place to start.0:23 The Standard Model of Particle Physics is our recipe book for the visible five percent of the universe.0:30 It's the most successful scientific theory ever written, and it is SO cool.0:36 Okay, a recipe book.0:37 I like that.0:38 So what are the ingredients?0:40 Great question!0:41 The ingredients are called particles.0:44 They come in two main families.0:46 First, you have the "matter" particles, the actual stuff.0:50 Scientists call them fermions.0:52 Fermions.0:53 Got it.0:53 Like flour and sugar?0:55 Precisely!0:55 And just like you have different kinds of flour, you have different kinds of fermions.1:01 The two most famous kinds are quarks and leptons.1:05 Quarks?1:05 That sounds like something from a cartoon.1:08 It does!1:09 But they're real!1:10 Quarks are the tiny, tiny particles that huddle together to make the protons and neutrons inside an atom's core.1:18 And leptons...1:19 well, the most famous lepton is one you know very well: the electron!1:24 Oh!1:24 The little things that zip around the outside of an atom?1:28 That's the one!1:29 So you've got quarks making the center of the atom, and electrons—a type of lepton—zipping around it.1:36 Those are your basic ingredients for, well, almost everything.1:41 Okay, so if fermions are the ingredients—the quarks and electrons—what's the other family of particles you mentioned?1:49 Ah, now we get to the ACTION!1:51 The second family are the "force" particles.1:54 They're called bosons.1:55 In our recipe book, if fermions are the ingredients, bosons are the verbs.2:01 They're the 'mix,' the 'stir,' the 'bake.' They tell the matter how to interact.2:06 So they carry the forces?2:08 Like...2:09 magnetism?2:09 Exactly like magnetism!2:11 The electromagnetic force, which covers electricity AND magnetism, is carried by a boson called the photon.2:18 When a magnet pulls on a piece of metal, they're actually exchanging zillions of little photons.2:25 It's like they're playing a game of catch, and that game of catch creates the force you feel!2:32 Whoa.2:32 So light—which is made of photons—is related to magnets?2:36 It IS the same force!2:38 Carried by the same particle!2:40 Isn't that amazing?2:41 It's all connected.2:42 That's just one of the three big forces in our recipe book.2:46 Okay, what are the other two?2:49 The next one is called the Strong Nuclear Force.2:52 And it is STRONG.2:53 It's what holds those quarks together inside protons and neutrons.2:58 The boson that carries this force is called...3:01 the gluon.3:02 Let me guess.3:03 Because it's like...3:04 glue?3:04 The strongest glue in the universe!3:07 It's what "glues" quarks together.3:09 And here's the wildest part.3:11 With a rubber band, the force gets weaker the closer you bring the ends together, right?3:17 Yeah, sure.3:18 Gluons are the OPPOSITE.3:20 The farther you try to pull two quarks apart, the STRONGER the force between them gets.3:26 It's like a cosmic rubber band you can never, ever break.3:30 That's why you can never find a quark all by itself in nature.3:34 They're always glued together in little teams.3:38 Okay, so we have the electromagnetic force carried by photons, and the super-strong force carried by gluons.3:45 What’s the last one?3:47 The last one is the Weak Nuclear Force.3:49 It's...3:50 a bit different.3:51 It's carried by particles called the W and Z bosons.3:55 The weak force doesn't really hold things together.3:58 Instead, it lets things CHANGE.4:01 Change how?4:01 It allows one type of quark to turn into another type of quark.4:06 This is the force behind certain kinds of radioactivity.4:10 It's like having a recipe where the flour can suddenly decide to turn into sugar.4:15 It's fundamental for how stars, like our sun, generate energy.4:20 Without the weak force, the sun wouldn't shine!4:23 So...4:23 Strong force glues things together, electromagnetic force makes things attract and repel, and the weak force lets things transform.4:33 And all of it is just particles playing catch with other particles.4:37 You've got it!4:38 Fermions are the LEGO bricks, and bosons are the different kinds of 'click' that connect them.4:45 And with that simple set of rules, that one recipe book, you can build everything from a flower to a planet to a person.4:54 But...4:54 not everything, right?4:56 You said this is just for the five percent of the universe we can see.5:00 And what about gravity?5:02 You didn't mention gravity.5:04 And that is the most exciting part.5:06 You are absolutely right.5:08 The Standard Model is almost perfect, but it's incomplete.5:12 It doesn't include gravity.5:14 And it has nothing to say about the dark matter and dark energy we talked about last time.5:21 It’s like we found the most amazing recipe book in the world, but we know there are entire chapters missing.5:28 And that means… there’s still more to discover.
