You probably already know everything is made up of little tiny things called atoms or even that each atom is made up of even smaller particles called protons, neutrons and electrons. And you've probably heard that atoms are small. But I bet you haven't ever thought about how small atoms really are. Well, the answer is that they are really, really small. So you ask, just how small are atoms? To understand this, let's ask this question: How many atoms are in a grapefruit? Well, let's assume that the grapefruit is made up of only nitrogen atoms, which isn't at all true, but there are nitrogen atoms in a grapefruit. To help you visualize this, let's blow up each of the atoms to the size of a blueberry. And then how big would the grapefruit have to be? It would have to be the same size of -- well, actually, the Earth. That's crazy! You mean to say that if I filled the Earth with blueberries, I would have the same number of nitrogen atoms as a grapefruit? That's right! So how big is the atom? Well, it's really, really small! And you know what? It gets even more crazy. Let's now look inside of each atom -- and thus the blueberry, right? -- What do you see there? In the center of the atom is something called the nucleus, which contains protons and neutrons, and on the outside, you'd see electrons. So how big is the nucleus? If atoms are like blueberries in the Earth, how big would the nucleus be? You might remember the old pictures of the atom from science class, where you saw this tiny dot on the page with an arrow pointing to the nucleus. Well, those pictures, they're not drawn to scale, so they're kind of wrong. So how big is the nucleus? So if you popped open the blueberry and were searching for the nucleus ... You know what? It would be invisible. It's too small to see! OK. Let's blow up the atom -- the blueberry -- to the size of a house. So imagine a ball that is as tall as a two-story house. Let's look for the nucleus in the center of the atom. And do you know what? It would just barely be visible. So to get our minds wrapped around how big the nucleus is, we need to blow up the blueberry, up to the size of a football stadium. So imagine a ball the size of a football stadium, and right smack dab in the center of the atom, you would find the nucleus, and you could see it! And it would be the size of a small marble. And there's more, if I haven't blown your mind by now. Let's consider the atom some more. It contains protons, neutrons and electrons. The protons and neutrons live inside of the nucleus, and contain almost all of the mass of the atom. Way on the edge are the electrons. So if an atom is like a ball the size of a football stadium, with the nucleus in the center, and the electrons on the edge, what is in between the nucleus and the electrons? Surprisingly, the answer is empty space. (Wind noise) That's right. Empty! Between the nucleus and the electrons, there are vast regions of empty space. Now, technically there are some electromagnetic fields, but in terms of stuff, matter, it is empty. Remember this vast region of empty space is inside the blueberry, which is inside the Earth, which really are the atoms in the grapefruit. OK, one more thing, if I can even get more bizarre. Since virtually all the mass of an atom is in the nucleus -- now, there is some amount of mass in the electrons, but most of it is in the nucleus -- how dense is the nucleus? Well, the answer is crazy. The density of a typical nucleus is four times 10 to the 17th kilograms per meter cubed. But that's hard to visualize. OK, I'll put it in English units. 2.5 times 10 to the 16th pounds per cubic feet. OK, that's still kind of hard to figure. OK, here's what I want you to do. Make a box that is one foot by one foot by one foot. Now let's go and grab all of the nuclei from a typical car. Now, cars on average weigh two tons. How many cars' nuclei would you have to put into the box to have your one-foot-box have the same density of the nucleus? Is it one car? Two? How about 100? Nope, nope and nope. The answer is much bigger. It is 6.2 billion. That is almost equal to the number of people in the Earth. So if everyone in the Earth owned their own car -- and they don't -- (Cars honking) and we put all of those cars into your box ... That would be about the density of a nucleus. So I'm saying that if you took every car in the world and put it into your one-foot box, you would have the density of one nucleus. OK, let's review. The atom is really, really, really small. Think atoms in a grapefruit like blueberries in the Earth. The nucleus is crazy small. Now look inside the blueberry, and blow it up to the size of a football stadium, and now the nucleus is a marble in the middle. The atom is made up of vast regions of empty space. That's weird. The nucleus has a crazy-high density. Think of putting all those cars in your one-foot box. I think I'm tired.
Droši vien jau zini, ka visu veido mazmazītiņas daļiņas — atomi. Varbūt pat zini, ka katru atomu veido vēl mazākas daļiņas — protoni, neitroni un elektroni. Noteikti esi arī dzirdējis, ka atomi ir mazi. Taču varu saderēt, nekad neesi aizdomājies cik mazi atomi ir patiesībā. Atbilde ir — tie ir ļoti, ļoti, ļoti mazi. Tieši cik mazi ir atomi, tu vaicā? Lai to saprastu, uzdosim šādu jautājumu — cik daudz atomu ir greipfrūtā? Pieņemsim, ka greipfrūtu veido tikai slāpekļa atomi, kas nepavisam nav tiesa, tomēr greipfrūtā ir arī slāpekļa atomi. Lai to iztēlotos, piepūtīsim katru no atomiem līdz mellenes izmēram. Cik liels tad būtu greipfrūts? Tas būtu tikpat liels kā... nu, īstenībā, Zeme. Trakums! Gribat teikt, ja es piepildītu Zemi ar mellenēm, tajā būtu tikpat daudz slāpekļa atomu kā greipfrūtā? Tieši tā! Cik tad liels ir atoms? Tas ir ļoti, ļoti, ļoti, ļoti mazs. Un zini ko? Tālāk ir vēl trakāk. Nu ieskatīsimies katrā no atomiem, proti, mellenē, ja? Ko tu tur redzi? Atoma vidū ir kas tāds, ko sauc par kodolu, kurā ir protoni un neitroni, un ārpusē redzami elektroni. Cik tad liels ir kodols? Ja atomi ir kā mellenes zemeslodē, cik tad liels būtu kodols? Varbūt atceries vecos atoma attēlus no dabaszinātņu stundām, kur uz lapas uzzīmēts sīciņš punktiņš ar bultiņu, kas norāda uz kodolu. Šos attēlus nezīmē pēc mēroga, tādēļ tie savā ziņā ir nepareizi. Cik tad liels ir kodols? Ja melleni pārkostu un meklētu kodolu... Zini ko? Tas nebūtu redzams. Tas būtu par mazu, lai saskatītu! Labi. Piepūtīsim atomu, t.i., melleni, līdz mājas izmēram. Iedomāsimies bumbu, kas ir divstāvu mājas augstumā. Pameklēsim tagad atoma centrā kodolu. Zini, ko? Tas būtu tik tikko saskatāms. Lai aptvertu, cik liels ir kodols, mums jāpiepūš mellene līdz futbola stadiona izmēram. Iedomāsimies bumbu futbola stadiona izmērā, un pašā atoma viducī varētu atrast kodolu. To jau varētu saskatīt! Tas būtu mazas lodītes lielumā. Tas vēl nav viss, ja jau neesmu samežģījis tavas smadzenes. Parunāsim vēl mazliet par atomu. Tajā ir protoni, neitroni un elektroni. Protoni un neitroni dzīvo iekšā kodolā un veido gandrīz visu atoma masu. Pašā, pašā malā atrodas elektroni. Ja atoms ir kā bumba futbola stadiona izmērā ar kodolu tās centrā un elektroniem malās, kas atrodas starp kodolu un elektroniem? Pārsteidzošā kārtā — tukša telpa. (Vēja skaņa) Tieši tā. Tukšums! Starp kodolu un elektroniem ir milzīgi tukšas telpas plašumi. Teorētiski tur ir elektromagnētiskie lauki, taču vielas un matērijas ziņā tā ir tukša. Atcerēsimies, ka šie milzīgie tukšās telpas plašumi ir iekšā mellenē, kas ir iekšā zemeslodē, kas patiesībā apzīmē atomus greipfrūtā. Vēl kas, lai padarītu lietas vēl dīvainākas. Tā kā teju visa atoma masa ir tā kodolā, — nedaudz masas ir arī elektronos, tomēr lielākā daļa no tās ir kodolā — cik tad blīvs ir kodols? Atbilde ir neaptverama. Tipiska kodola blīvums ir četri reiz desmit 17. pakāpē kilogrami uz kubikmetru. To ir grūti iztēloties. Pārvērtīšu to angļu mērvienībās. 2,5 reiz desmit 16. pakāpē mārciņu uz kubikpēdu. To ir joprojām pagrūti saprast. Labi, darīsim tā — izveidojiet aptuveni 30 reiz 30 centimetru lielu kasti. Tad paņemsim visus atomu kodolus no tipiskas automašīnas. Mašīnas sver vidēji divas tonnas. Cik daudz mašīnu kodolu būtu jāieliek kastē, lai mūsu 30x30 cm kastei būtu tāds pats blīvums kā atoma kodolam? Viena mašīna? Divas? Varbūt 100? Nē, nē un nē. Atbilde ir daudz lielāka. Tie ir 6,2 miljardi. Tas ir gandrīz tikpat, cik uz Zemes ir iedzīvotāju. Ja visiem uz Zemes būtu sava automašīna, — visiem gan nav — (Taurējošas mašīnas) un mēs visas šīs mašīnas ieliktu tavā kastē... Tā būtu apmēram kodola blīvumā. Tas nozīmē, ja mēs paņemtu visas pasaules mašīnas un ieliktu savā 30x30 cm kastē, mēs iegūtu viena kodola blīvumu. Labi, atkārtosim. Atomi ir ļoti, ļoti, ļoti mazi. Iedomājieties atomus greipfrūtā kā mellenes zemeslodē. Kodols ir trakoti mazs. Apskatot melleni, un uzpūšot to līdz futbola stadiona izmēriem, kodols būtu vidū esoša lodīte. Atomu veido milzīgi tukšas telpas plašumi. Dīvaini gan. Kodolam ir trakoti liels blīvums. Atceries par visām tām mašīnām 30x30 cm kastē. Es laikam esmu piekusis.