Hi.
I'm at Patrick Lee from Deerpath Middle School.
I'm in fifth grade.
And my question is do you think hydraulics
could help people with knee problems when
their knee breaks down and it could help it
go down much softer?
Patrick, let me start by saying that is a
fabulous tie.
Way to go man.
It looks good.
You know, people are skeptical to pink.
I like the pink.
I like the purple.
I think it's good.
Good choice.
That is a great question, could hydraulics
help somebody's knees?
There's a great word they use in medicine
a prosthetic, meaning an artificial limb.
I got to say yes absolutely.
I don't know how familiar you are with hydraulics
but you asked about it, but the idea is hydro
is a word for water and hydraulics use fluids,
which do not compress very much.
Water hardly compresses at all, if you squeeze
it hardly anything happens.
And the same is true of the oil in the transmission
of cars.
And the oil that's in the pistons, the shock
observers of the car and it's very reasonable
that this would work.
Because what hydraulics do is so fabulous
is they provide a tremendous amount of force
from a small object, a small actuator.
And the other thing they really help with
is what's called damping, which used to be
called dampening.
But the faster you move something the more
damping slows it down.
It sounds tricky but it's not.
You've done it.
So what happens in a hydraulic actuator they'll
have an opening, which is another I think
it's a Greek word an orifice.
So when you try to squeeze the oil or the
water through that opening it slows it down.
And the faster you try to go the more it slows
it down and this has to do with the nature
of fluids.
And there's a whole study in physics called
fluid mechanics, but yes that is a great idea.
You're going to be an inventor Patrick.
Way to go man.
Let me tell you, I used to work at Boeing
on the 747 airplane, which is getting to be
an old airplane now but the president still
flies around on a 747.
It's a Boeing plane like a 757, 767, 737,
787.
Anyway, there's two things I worked on a lot,
one of them was a rudder and that's the thing
that steers the plane this way.
And that thing is so powerful.
So there's a pump – there's four pumps by
the engines and each pump is unbelievably
reliable and just they work for years and
years because the thing they pump is oil so
they're always getting lubricated, they're
always slippery inside which keeps things
from wearing out.
Anyway, those pumps make 3000, we used to
all do it in English units, pounds per square
inch.
As they say, if you want to move a house,
if you want to move the Washington Monument
that far in a 20th of a second, a 747 rudder
actuator will do it for you.
And so that is a great idea man.
You can get so much force in hydraulics and
a knee could be the perfect place for it.
Now just notice when you go to do it you're
going to need a place for the actuator to
push and you're going to need something to
pull with.
In my day, I'm sure it still is, this is called
a wishbone crank because it's kind of like
a wishbone.
You're going to need a force and you're going
to need a lever, something that's not quite
in the same access as the force.
You'll figure it out.
That is a great idea Patrick.
Be an inventor.
Change the world.
Nicely done.
You know what Patrick, I bet you have someone
in your life who needs an artificial knee.
Help him or her out.
Way to go.
