Fun Video: Mechanical Engineering Video Lecture

Mechanical engineers have changed the world.
You could even say: the course of history.
Not just once but countless times.
Because they’ve identified problems that were
holding humanity back, and they solved them.
Things were too big and heavy to move.
Travel was too difficult.
Distances too far.
Our bodies were too weak.
If you can think of an invention that
revolutionized the way people live, odds are
it was created by mechanical engineers.
And I don’t think I’m being biased.
Theirs is the field of engineering that focuses
on the design, construction, operation, and
maintenance of machines and mechanical systems
– pretty much anything that moves.
And since the beginning, mechanical engineering
has faced a great many challenges, and solved
a lot of problems.
The examples are too many to count, but consider
things like the steam engine, airplanes, robots, and
biomechanical suits.
The engineers behind all of these devices
were able to find solutions to big problems.
And of course, they faced difficulties along
the way.
But great efforts almost always do.
[Theme Music]
Back in the day, if you wanted to get somewhere,
you would have had two options: your own two
feet or a horse.
And if you wanted to take a heavy load with
you, you needed a carriage. Wheels.
The invention of the wheel is one of the oldest roots
of mechanical engineering, along with all of the simple
tools that went into building the carriage itself.
If we include the simple levers that were used to
open gates and bring down bridges, we’d have a great,
but primitive, base of early mechanical engineering.
But horse-drawn carriages aren’t very fast.
A horse needs rest and food, so it would be generous
to say you could cover 80 kilometers a day.
This gave the engineers of the past a problem.
As the world opened up, it became more
important to cover distances in less time,
and horses just weren't cutting it.
They needed something faster.
They needed an engine.
Making its first appearance in the early 18th century,
the steam engine marked a major turning point in the
development of modern mechanical engineering.
It was proposed that a steam engine could
do the work of ten, fifteen, or even twenty horses!
And you wouldn’t need to bother with any
hay...or manure.
This brings us to Thomas Newcomen, the British
inventor who developed the first successful steam
engine with a piston in 1712.
In his design, atmospheric pressure pushed
the piston down, after the condensation of steam
had created a vacuum in the cylinder.
Its original use was to draw water out of the
Cornish tin mines, after Newcomen found how
expensive it was to use horses to pump the water.
Then along came the Scottish inventor James
Watt.
In 1763, while repairing one of Newcomen’s engines,
Watt realized that about three quarters of the
energy from the steam was going to waste, used
only to heat the chamber of the engine.
His solution was to have a separate condenser.
The steam would then be condensed in a
chamber separate from the piston chamber, so that
the condensed steam didn't go to waste.
Keeping the two processes separate allowed
for continued rotary motion, which was really
important,
because it allowed for a more consistent
source of power.
Watt’s invention came to be widely used
to run machines in the factories that drove
the Industrial Revolution.
Watt went on to be the first engineer to be
commemorated in Westminster Abbey, with a large,
white marble statue erected in his memory.
He also had his last name recognized as a
unit of power, which is perhaps one of the
highest honors that an engineer can get.
But steam engines really came into their own,
especially in the realm of transportation, in the
locomotives of the 19th century.
George and Robert Stephenson, an English father-son
duo, are famous for their early steam locomotive, which
they called, aptly enough, “Locomotion.”
In 1825, it became the first public passenger train,
carrying 450 people at 24 kilometers per hour.
Quite a bit faster than a horse!
But while wheeled vehicles allowed people to travel
more quickly on land, transportation was still limited
by bodies of water and rough, mountainous terrain.
If engineers could figure out a way to get
people to fly, all of that could be avoided!
This problem-solving led to the invention
of aircraft.
The first powered aircraft to take flight was the Wright
Flyer in 1903, which was designed by Wilbur and Orville
Wright and used a 12-horsepower gas engine.
Orville flew the Wright Flyer on its maiden
voyage, traveling 36 meters in 12 seconds.
But the best flight of the day belonged to Wilbur,
who traveled over 255 meters in 59 seconds,
or a speed of about 15 kilometers an hour,
earning him some serious bragging rights.
Soon after the Wright brothers’ accomplishment,
World War I sparked a burst of aircraft innovation.
Engineers began using metal in the structures
of the airplanes, and better engines, allowing
them to reach higher speeds and altitudes.
Then, in 1930, Sir Frank Whittle obtained
his first patent for a turbo-jet engine.
But it wasn’t until the outbreak of World War II
that the British government had a compelling
reason to support his work.
By 1941, Whittle’s engine featured a multistage
compressor, a combustion chamber, a single turbine,
and a nozzle –
which was a big improvement, since previous
engine designs only had an internal-combustion
engine and a propeller.
Jet engines outperformed the older designs,
flying farther, faster, and cheaper too.
These advances ultimately made commercial
air travel possible, and soon people were traveling
where once only the birds had ruled.
But mechanical engineering doesn’t stop
in the air!
Beyond planes, we’ve sent satellites into
orbit, astronauts to the moon, and spacecraft
carrying rovers all the way to Mars.
The aerospace side of engineering actually
arose from the mechanical field.
And much of what has allowed us to build these
machines that move us is another big part of the
mechanical engineering field: robotics.
For most of industrial history, humans have
been at the center of our workforce.
But humans have their limits.
Some things are too big and too awkward to
move, while other processes needed a finer
precision than the human hand allows.
Industrial environments are also often uncomfortable
and sometimes even dangerous.
And that’s where robots and automation come in.
The first industrial robot, called Unimate,
appeared around 1960.
It was designed by American inventor George
Devol, Jr., who worked with engineer and entrepreneur
Joseph Engelberger to get it into factories.
Unimate robots had up to six fully programmable
axes of motion and could handle parts weighing
up to around 225 kilograms at high speeds.
They soon joined the assembly line at a General
Motors plant, where they took die castings from
machines and welded them onto auto bodies.
Since then, robots have gone beyond manufacturing,
showing up in our homes to clean the floors, and
even hospitals to perform surgeries.
But as their applications get more advanced,
engineers have more and more factors to consider.
They need to worry about how well robots sense
their surroundings, how they move and manipulate
their environments, and much more.
It’s possible one day that we’ll have
robots in many of the places you could
imagine a human working.
I mean, we’re seeing that now.
And speaking of humans, you can think of the human
body as just a super complex mechanical system of
its own, made of links and connecting joints.
And this is where biomechanics comes in.
Engineers need to take into account the stress,
load, and impact that our bodies can withstand,
and apply it to machines that are modeled on us.
Advanced biomechanics is one of the newest
divisions of mechanical engineering.
From it, we’re already seeing the beginnings of
exoskeleton-suits, limbs that move like their biological
counterparts, and other robotic implants.
One of the more impressive projects is the
Berkeley Lower Extremity Exoskeleton.
Funded by the Defense Advanced Research
Project Agency in 2000,
this device is designed to provide mechanical
support to allow nearly anyone to carry larger, heavier
loads than they could ever lift on their own.
The ability to carry heavy loads is often a problem
for soldiers and disaster relief workers, so finding
a solution to this is pretty important.
But the problems are many.
For one thing, power sources for exo-suits
are often too heavy or cumbersome.
But the BLEEX, as it’s called, overcomes
this by using a small hybrid power source
that delivers hydraulic power for the suit’s
locomotion and electrical power for its computer.
The first prototype was recently introduced,
consisting of two powered, anthropomorphic legs,
a power unit, and a backpack-like frame.
Using the frame, a person can carry a heavy
load, but only have it feel like a few pounds.
In similar fashion, Berkeley is also behind the
Austin project, which aims to develop exoskeleton
systems for people with mobility disorders.
So it’s almost as if we’ve gone full circle,
from the inventors who developed the first
steam engine to replace the horse,
to the biomechanical engineers who are
using robotics to simulate the most basic
means of transportation: walking.
Those are some of the very big problems that
mechanical engineers have managed to solve.
And when it comes to the problems that we
still face today – from driving in traffic to getting
food and water to remote areas –
you can bet that mechanical engineers
will be there to tackle them.
So today we learned all about many different
areas of mechanical engineering, beginning
with the steam engine.
We then moved on to aircraft and the work
behind them.
And we finished by going into the more modern
areas of robotics and biomechanics.
In the next episode we’ll explore electrical
engineering, its history, and the work that
electrical engineers do.
Thanks for watching and I’ll see you then.
Crash Course Engineering is produced in association
with PBS Digital Studios.
You can head over to their channel to check
out a playlist of their latest amazing shows,
like PBS Space Time, Above the Noise, and
Physics Girl.
Crash Course is a Complexly production and
this episode of was filmed in the Doctor Cheryl C.
Kinney Studio with the help of these wonderful
people.
And our amazing graphics team is Thought Cafe.