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DIANNA COWERN: Thanks to Bill and Melinda
Gates for supporting PBS Digital Studios.
Robert, are you ready?
So this is Robert.
He's my roommate.
Hi.
He also happens to be a physicist.
So Robert, this is my device, co-designed and made by Kyle.
Have you heard of a ShakeWeight?
I have not heard of the-- what?
You shake it like this and get a good workout.
All right.
Yeah-- so we modified this ShakeWeight so that
there's a magnet connected to a rod.
And the magnet goes back and forth
between this coil of wire.
And the coil is connected to an LED
so that-- do you want to try it?
All right, I'll try it.
OK, hold on.
Hold on.
Why are you putting on safety goggles?
Oh, you see it?
Yep.
It's working!
Thank you for demonstrating.
In your expert opinion, how cool is this invention?
It's definitely very pretty, especially here
with the reflecting surfaces.
Oh, that came with the ShakeWeight.
OK, thank you, Robert.
I think he liked it.
The purpose of this modified ShakeWeight
is to see how much electrical energy
we can make, using electromagnetic induction
and starting out with kinetic energy.
Then the last thing I want to figure out
is, how long would it take, using this device, to produce
enough energy to power a house for an entire day?
I'm going to need a way to measure the energy.
You guys know that I'm pretty excited about science.
I want us to send things to Mars.
And not just things that rhyme with Mars--
Elon.
But also, I want us to be responsible earthlings.
If we want to curb our carbon emissions,
we're going to have to change the way that we produce and use
energy.
Here's my contribution.
I promise this is all going to tie back together
later in the video.
But in the meantime, now we need a way
to figure out how much power we're outputting with this.
I'm going to replace the LED with a resistor and Arduino
that I've programmed to show the voltage across the resistor.
Ha!
Resistors-- and then we can use that voltage in the resistor
to figure out the power.
Now, the way that we're getting power is the cool part here.
The only thing we have is a coil of wire
and a permanent neodymium magnet on a rod,
going back and forth through the PVC pipe.
And now, Lenz's law here tells us
that, when you have a changing magnetic field, like that
of a moving permanent magnet, you
can induce an electromotive force in a coil of wire.
An electromotive force is like it pushes the electricity.
In our case, the electricity can flow.
So we get a current in the coil.
That's what lights up the LED.
There's no battery, no outlet, no source of power
besides what we've made here.
Heh, time to pretend I know what I'm doing.
Yah!
It works.
I made this.
Go talk with the more scripted organized Diana
about clean energy.
And then come back.
So I care a lot about this issue of clean energy
and where it comes from.
Or at least, that's what I say.
Now, if I really cared, I would be an expert on the subject,
right?
So I have this idea to quiz myself
of questions about the clean energy industry
and where we stand in our progress.
But I swear, I came up with the questions
off the top of my head.
And I didn't do any research before I answered them.
This is a dangerous thing to do on the internet.
I totally suggest that you play along.
And I would love it if you put your answers in the comments.
OK, first question-- what percentage of energy in the US
comes from clean energy?
I think this is the most important question.
I guessed 35%.
I don't even know if that's low or high.
I don't know.
The answer is, 10% of US energy, 15% of US electricity
is from renewables.
Ooh!
OK, the difference in numbers here-- the 10% versus the 15%--
comes from the fact that not all of our energy
is used toward electricity production.
In fact, most of it's not.
Electric power is only 39% of energy use in the US.
Biggest one after that is transportation,
which is actually 29% of all of our energy.
Industrial is about 22%.
Factories use a lot of energy.
And then residential-- 6%.
And commercial is 4%.
So of our electrical power, it's higher.
It's about 15%.
And then of our total energy production,
it's 10%, which makes sense.
Until we have electric cars, it's
harder to do transportation with clean energy.
You need to worry about storage.
We've got a long way to go.
I feel like that's depressing.
I'm going to draw a graph.
I'm going to graph out since--
I don't know-- like, 1960, say, until now,
what I think the percentage energy usage has looked like
and then compare it to the real graph.
OK, so here's my graph.
And the real graph--
whoa-- 1990s, what were you doing?
But yeah, OK.
This is good news.
Let's compare the two graphs.
So this means that I underestimated clean energy
in the early decades, because I forgot about hydroelectric.
But looking at the present day, we're
making progress much faster than I thought.
Look at that slope!
Yeah, that's good.
It means that we're making quick progress in the technology.
Whoo-- OK.
The last question that I didn't guess,
but I looked up, because I was curious during this quiz
is, how much energy are we using total in the United States?
Again, we've got transportation.
We've got industry.
We got all these different sectors using energy.
In the US, we use $28 trillion kilowatt hours per year.
Ugh!
And that's going to go up by 20% by 2040.
So it's going to be 35 trillion kilowatt hours per year.
That's 80 trillion kilowatt hours per day.
That's 80 billion people playing Mario Kart for 10 hours a day.
We don't even have 80 billion people on the planet.
These are mind-boggling numbers.
And finally, if you shake the ShakeWeight flashlight,
you can produce--
OK, final calculation.
The average power produced by the ShakeWeight is--
drumroll-- 0.004 watts.
Yes!
So given that a house uses 30 kilowatt hours a day,
it would take 7,500,000 hours to produce enough energy to power
a house for a day.
Oh, what?
7.5 million-- that's 312,000 days--
856 years of constantly shaking the ShakeWeight
to produce energy for every single waking
minute of your day.
Well, I give up.
So I'd say, the biggest surprise to me
was the magnitude of these numbers
and how little electricity I was able to produce
with the ShakeWeight.
Of course, most of it was going into heating up my muscles.
It wasn't a very efficient system.
And obviously, I was way too optimistic on our progress
so far toward clean energy.
But I was a lot less optimistic on the trend that we've made.
So that means that we're making progress fast.
And we can make progress fast.
And with minds like yours--
creative minds that are working to improve clean energy
technologies to come up with new ways of improving renewables--
I've got a lot of hope for the future.
Thank you so much for going on this learning journey with me.
And happy physicsing.
I'd like to thank Bill and Melinda Gates for supporting
PBS Digital Studios.
As I'm sure you know, Bill and Melinda Gates
are also very outspoken about their optimism.
In their annual letter for this year,
for 2018, they're sharing some of the challenges
that they face in their work and addressing
why, despite some of the headlines that we might read
or news we might see, they believe there's still
a case for being an optimist.
You can learn more about their work
and why they're so optimistic at gatesletter.com.
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