The Biggest Ideas in the Universe | 1. Conservation

[Correction: at 17:51 I say kinetic energy is a vector, I meant to say "scalar." Kinetic energy has a size, but doesn't point in a direction.]

The Biggest Ideas in the Universe is a series of videos where I talk informally about some of the fundamental concepts that help us understand our natural world. Exceedingly casual, not overly polished, and meant for absolutely everybody.

In this installment - the very first idea we cover! - I talk about "Conservation." The idea that a certain property, like momentum or energy or electric charge, stays the same over time. In my view, realizing that this is true - and the corollary, that the world naturally moves, rather than needing something external to keep it moving - represents the real transition between pre-modern and modern physics.

#science #physics #ideas #universe #learning #cosmology #philosophy #math #conservation #momentum #energy #classicalmechanics

[ohmultiverse]

Some people's personalities just...shine. Or rather, they shine through. One only has to watch Sean Carroll for a little while to know, to a high degree of certainty, that he is not only highly intelligent, but also that he has a wonderful wit, is a kind human being, is fundamentally optimistic, and is thoroughly unpretentious. Thanks so much for creating this series Dr. Carroll.

[thenorseman]

You, Dr. Carroll, are a worthy candidate to be this newest generations' "Great Explainer." Please accept this humble gift of an imaginary Spherical Feynman to sit proudly next to your Cow.

[seancarroll]

Leave questions here, over the next couple of days I'll pick some favorites and try to answer them in a separate video. (Not "ask me anything, " but "ask me about stuff discussed in the video.")

[jms]

17:51 - you meant to say kinetic energy is just a scalar! I don't know if youtube still allow annotations so that you can put an onscreen correction. Alas I don't think so...

[Grinsekatze]

Pro tip: I don't know what you are using for video editing but somewhere you should be able to adjust the colours. Lower the green values, maybe cyan. That's an easy way to clean up the edges and even the light scatter. Greetings from Germany, keep it up!

[ratedAD]

Sean, please keep doing this! You truly have a gift. Love your work and your passion for educating the uninitiated. I'm 36 and deeply regret not taking physics more seriously growing up. Your lectures and videos are such a source of intellectual nourishment for me.
I am a regular listener of your Mindscape podcast and a Patreon supporter. Please keep producing more work that benefits people like me who are not trained in the math but are curious about the big questions nonetheless. Cheers! Please stay safe!

[wasimshaikh]

Man u deserve a Nobel prize for your explainations👏👏
I wish my physics teacher was like him🤔

[houndofzoltan]

When Americans talk I can't tell the difference between their pronunciation of Plato and Play-doh.

[integza]

I love this! Great idea! It's an honor to have you here on YouTube, Sir.

[MoreChazImages]

Great start, you kept it interesting - just like your books - and a spherical cow bonus, wow!

[dlabs]

9:58 Love that you put an arrow below the arrow - - wonderfully redundant :)

[seffundoos]

Thank you Sean. You are really leaving some wonderful things for today's generations and future ones alike.
I especially like your take on the purpose of physicists and the way you have not been scared to delve into the world of the implications of quantum mechanics.
There is no doubt that you will be the inspiration for countless physicists to come!
Thanks again for the exceptional content.

[DaKoopaKing]

Loved it but it was too short! I would've loved to hear about Noether's theorem and how conservation connects to higher level physics.

[lukeworldwide]

Thanks Sean so much for this series. I didn't get to study much maths and physics at school, so this level of conceptual explanation of these important concepts is fantastic for me.

[macdeepblue]

Economics definitely uses spherical cows. Here's a joke economics tell each other:


A ‪‎physicist, an ‪‎engineer and an ‪‎economist are stranded in the desert. They are hungry. Suddenly, they find a can of corn. They want to open it, but how?
The physicist says: “Let’s start a fire and place the can inside the flames. It will explode and then we will all be able to eat”.
“Are you crazy?” says the engineer. “All the corn will burn and scatter, and we’ll have nothing. We should use a metal wire, attach it to a base, push it and crack the can open.”
“Both of you are wrong!” states the economist. “Where the hell do we find a metal wire in the desert?! The solution is simple: ASSUME we have a can opener”…


But you're right in that one of the big tensions in economics is when theory and empiricism clash (e.g., minimum wage) and that's probably not as big of a deal in Physics, where it's much easier to test.

[billlyons]

Your videos are a bright spot in this crisis. Thanks for making them.

[manvendrasomvanshi]

I think you should have mentioned symmetries and how they are connected to conservation laws (Noether's theorem). I personally think that Noether's theorem is one of the most beautiful things that exist in physics.

I know that historically it came very late, but still I it should have been mentioned.

[CHXFIT]

I love this guy. Taking this class seriously. You inspired me to learn physics a few years ago when you got onto JRE and I haven’t stopped learning since. Thanks Sean. Also plan on purchasing your books as soon as I have some extra money.

[ghislaindebusbecq]

As a non-native English speaker, I find Sean Caroll speaks one of the most understandable and agreable English I've heard from English people. Robert Eagle from Dr. Physics A channel is also very understandable and agreable. Why all English people are not physics specialists ?

[JasonWalsh-bn]

MICROSCOPIC STUFF AND MACROSCOPIC STUFF IS INTERESTING. IMMATERIAL "STUFF" IS (YAWN) NOTHING.❤