
Alright everyone, welcome back to Cody's lab.
So, as you can see here, I have a 100ft length of blasting wire.
This is the same stuff I used in my episode 6 of my mining project.
I've affixed to it a small light bulb, as you can see there.
You see...
what we'd figured happened when I tried to detonate the explosives with the wire and the blasting generator
is the wire was just so long that that the resistance built up that the fuses to set off the powder...
were not-- which are basically the same as this light bulb just without the glass cover
were just not getting enough power to actually set off the gunpowder
So, here's a 1.5 volt alkaline battery
...and lets hook the leads of this directly to this light bulb.
and you'll be able to see...
that it does light up pretty nice-- see that?
It lights up.
Now--
the battery is hooked
through the wires so the battery is being hooked
through 100 feet of wire..
Let's touch these ends together
and you'll see you get basically nothing
I can see a little tiny glow there
but that's not very much.
That right there would be enough to set off gunpowder
but even this battery is better than my blasting generator
because the blasting generator only produces a charge that lasts like this long
See, you don't even see it light up
through that.
So let's actually hook this through this multimeter here
Okay, so there we go
It's hooked up to the multimeter as you can see we're getting
we're getting 1.48 Volts.
which is what I'd expect from this battery
Let's put this on milliamps
See, I'm roughly getting 109 milliamps through this-
-system.
Now, one person suggested that I
cool the wire off to decrease it's resistance.
This would be absolutely absurd to do in the mine
because it'd take a lot of work to cool it off and I
may as well just get bigger wire if I'm gonna spend the trouble to cool it off..
But it got me thinking: "What would happen if I actually did cool this wire off-"
"-as cold as I could get it?"
Say...
with some liquid nitrogen.

Would this light
get brighter?
Would I be able to put more current through it
because the resistance of the wire actually decreases?
So let's put this

inside this Dewar flask
alright, there we go, its all hooked up
Let's add the nitrogen and see what happens.

I can see the amperage is already increasing

It's up to 126, now.

Alright.

All the nitrogen is in.
I don't see anything happening with the light bulb.
eh, it's glowing a little bit.
The multimeter must be taking a lot of resistance through it as well.
There's the coil in the nitrogen.
So that's rather interesting, it seems to have lowered
lowered the resistance a little bit
and that increased the amount of current that is moving through this wire.
Let's take this coil out now..
If I can..
Stuck--There we go.
and let's plunge it into warm water and see what happens.
Here we go--It's making a lot of fog
submerge this completely
warm it up

Oh, I must have unhooked something, hold on.
Alright, we're back up to around 110-
-milliamps-
-now that it is warmed up.
So let's actually take the multimeter out now
to reduce that amount of resistance
That way we can get the bulb glowing again
and let's actually dim the lights
Let's see if we can see this thing brighten when I put it in the nitrogen.

I should say it got brighter, look at that!
The multimeter didn't seem to show much of a change
but, then again, the multimeter was also a significant source of-
-resistance to the circuit.
Now I'm going to take this coil of water and dip it into this warm water.
Ooo-freeze my fingers here.
Okay.
Here it is.
It's going into the warm water
Look at that.
It gets dimmer almost immediately.
It's all but gone.
Look at this, the coil is completely frozen with water.
Ha-Ha.
It's hard as a rock.
Now I'm sure there are some of you out there who are
able to deduce the amount of resistance
that was in the wire and the amount that it dropped
just by using Ohm's law.
And for the rest of you, you were screaming at the screen
asking me to just use the Ohm function on the multimeter.
So, as you can see, in this coil we have
1.4 Ohms of resistance
now let's add the nitrogen and see how much that drops

That's dropping significantly, isn't it?


There we go.
We're clear down to 0.1 Ohms.
Ha.
Zero.
So it's-it's within the detection limits of this multimeter here.
So that is a significant drop in resistance in that wire.
No wonder the light bulb got so bright.
So now I am going to answer the question as to why it's actually becoming a low resistance as I get it cold.
and the answer is that it is actually a quantum phenomenon.
You see, as I constrain the momentum of the particles in the material,
basically, get them colder, reduce their kinetic energy
I am actually increasing the uncertainty as to where those particles are.
See, it's the Heisenberg uncertainty principle.
As the momentum is constrained and known better
then the actual location becomes uncertain.
'cos you can never know both at the same time.
This causes the particles to basically expand their probability space
which makes it easier for the electrons to jump between the atoms
'cos its essentially like their wave functions are expanded--they're actually bigger.
so its easier for them to jump across the gaps
which decreases the amount of energy it takes
in order to actually get them to jump across and move through the wire-
-lowering its electrical resistance.
and now, as you can see as its warming up
and I'm increasing the kinetic energy of the particles
then I'm allowing the electrons to be known more
specifically in their location
So it's increasing the resistance again.
Since I have the nitrogen out and am talking about electricity and resistance
I thought I'd try another experiment here.
I have an aluminum plate
and a large magnet.

Now, if I take the magnet and move it next to the plate
without touching it, you can see that I can move the plate.
This is because the magnet is inducing an electric current in the metal
and the electric current is producing an opposing magnetic field
which causes resistance to all motion, you see
It's not attracted to the plate, but it is--
--but it does move with it because it is trying to inhibit the motion.
This is actually--the way this works is similar to how if you are spinning an electric motor, a DC electric motor
and then short out the terminals how the motor will suddenly stop
or become very difficult to turn.
That's because it takes work to move those electrons around.
The magnet is moving electrons--it's taking work to do it--
and so its really not favorable for the metal to
continue moving with respect to the magnet.
As you can see, I can get it spinning
then, I can stop it.
Without even touching it.
Everything that conducts electricity exhibits this behavior, even mercury.
As you can see here.
I'm not touching it with the magnet, but the magnet is definitely interacting with the mercury.
See that?
Because this is an electrical effect, the better the conductor is, the stronger this effect will be.
If this was a silver plate, I might even see better results.
Now, we just proved that cooling off the metal reduces it's resistance
so let's see what happens when I pour liquid nitrogen into this metal plate.
If it has a-a stronger effect, maybe.
I don't know, I've never tried this before.

This is going to be interesting, heh-heh.

There we go.
Now it's startin' to stick.

That's kinda cool, actually.
Once the nitrogen finally reach--once the aluminum actually got cold enough
for the nitrogen to actually start sticking to it--
--it just finally cooled the rest of the way down.
Ooo, Oo, that's cold. Ha-ha-ha.
Okay..

Oof, now we got a very cold plate.
Let's see if the magnet has any bigger effect on it.
Oh yeah!
That is significantly better.

See how much faster I can get that..
and how fast it stops?

That is cool.
So being cold definitely increased the eddy current effect on it.

Very cool.

Ha. Ha.
Alright, one last experiment.
Let's hook this battery straight up to the light bulb
and let's see what happens when I cool the battery off with liquid nitrogen.
Will the light bulb stay lit?
Alright, here goes.

This might take a while to cool it off completely.



Oh yeah, look, that light's getting dimmer.

--and gone, there's nothin' comin' out of it.

I guess batteries can't handle the cold.
Electrons can't really flow through an electrolyte if
the electrolyte is frozen solid..
Hah-hah.
Well,
I'm going to set this ont he counter for a few minutes and see if it actually
recovers and see if that light turns back on.
Hey, look at this!
I think the, uh, battery might actually be recovering.
See that, the light's actually on.
..A little bit.
So I guess the battery might have survived.
Yep, as it lights up, that light is definitely getting brighter.
Anyway, hope you all enjoyed,
and I'll see you next time!





