- Hello, hello.
Welcome to Dianna's Intro Physics Class,
also known as AP Physics 1 Review,
also known as Physics by Dianna.
I am so excited for this,
because this is gonna be an actual class.
And starting today, we have 20 lessons together -
(explosion rumbling)
Whoa!
- to get really into what physics is all about and
investigate the phenomenon that got me hooked
on this subject.
Let's first answer a question that I wish we taught kids
way earlier in life, which is, "What is physics?"
Some people will say,
"Physics is studying far away galaxies," or
"It's smashing small particles together at the large
Hadron Collider" or
"Physics is a bunch of word problems on a test you have to
take to get into college."
And the thing is, they're all right,
but if I were to sum it up,
Physics is a tool,
an incredibly versatile, extremely powerful tool.
Physics put people on the moon.
It's what made our phones work and the internet possible.
It's how we listen to collisions of black holes on the other
side of the universe.
So what is this tool that is Physics?
Take a look around us.
Ask a question that you want to understand
and then figure out how to measure it with numbers.
And then you make a mathematical model based on those
numbers.
That's it. That's the whole game.
It sounds simple, but it has taken humanity
thousands of years to figure all of this out.
Like Aristotle, who thought the heavier objects fall faster.
And then Galileo who showed that that was wrong by dropping
balls off the Leaning Tower of Pisa,
although that story was probably made up.
But Aristotle was wrong.
And then Newton figured out that a simple theory of gravity
explains how planets orbit the sun and Einstein figured out
that actually Newton's picture was incomplete and that we
all live in a four-dimensional space time that's warped near
large masses, duh.
And then Vera Rubin,
who looked up at the sky with her telescope
and discovered that galaxies are rotating way too fast
and there must be something invisible holding it all
together, that we now call "dark matter."
P.S. We still don't know what dark matter is and people are
looking for it today.
So in this course,
we're going to understand what all of these scientists
figured out.
We're going to cover kinematics, Newton's laws,
collisions, circular orbits, and at the very end,
we'll even get to a little bit of electricity and magnetism.
And I might even tease some crazy facts from quantum
mechanics and relativity and cosmology, if you're lucky.
To get more detailed about what you can expect in this
course,
here are the objectives:
Newton's laws.
We will analyze behavior of the physical world using
Newton's three laws of motion.
Energy.
We're going to use energy as a tool to model and predict
changes in physical systems.
Conservation laws.
We're going to understand and apply conservation laws,
which limit what is legal in our universe.
Waves.
We're going to model and predict the properties of
mechanical waves.
And I'm sorry, but you're going to start to see them
everywhere.
And electricity and magnetism.
We'll take a look at what the heck electromagnetic radiation
is and how it interacts with matter.
So if you stick with this course,
you'll be able to start seeing the world like a physicist
and answer questions about the real world using math.
That's what all those scientists,
people that I mentioned and thousands more have done.
They have figured out this game
that if I just find a mathematical model that matches simple
measurements I've taken about my world,
then I can check that model with my friends
and what pops out is an incredibly sophisticated explanation
of the universe.
But there's more,
I can use the models to predict the future.
We do this every day with tides and eclipses.
We know when they're going to happen.
But there's more.
We can sometimes fit our models together to predict some new
feature of the universe that nobody had ever even seen.
Like the existence of a planet, like Neptune.
We predicted that.
Or anti-matter, which is real.
It was predicted by math, alone.
And this incredible process of explaining what the heck is
going on around here is still happening today.
We're living in a golden age of physics
and I'm so glad that I live now.
But I'm mad that I live now and I won't get to see what new
stuff people are going to come up with in 500 years.
But the tool that got us here
and the tool that's going to get us there
to wild new discoveries and theories is physics.
I hope you stick with this course,
but more importantly,
I hope you maybe develop a love for curiosity about physics.
(gentle music)