Vsauce, I’m Jake and you can’t see me right now even though I am directly in front
you.
Since there is no light in the room there is nothing in the visible spectrum for you
to see, but that doesn’t mean that there is nothing here.
Let me show you…
Using a FLIR Thermal Imaging camera we get a visual representation of thermal radiation,
or infrared radiation, the heat transfer by the release of photons.
Thermal cameras report a temperature value, the effect of temperature.
Instead of seeing the visible light of an object, it estimates the infrared radiation
an object is emitting.
And you can tell that my nose is colder than the rest of my body and you can see everything
around me, because everything above 0 kelvin, a temperature that we have never achieved
or witnessed, glows.
But generally we don’t see it since the emitted photons are not in our visible range.
Also it looks just like Predator vision from the movie Predator which is what inspired
me to borrow this camera in the first place.
Let’s turn the lights on for a second.
Ok, everything looks normal again.
And I have a refreshing, cold beverage in an aluminum can.
You know it is cold because I just said it was but if we switch back to thermal mode,
you can see the extreme temperature disparity between my body and the can.
Also I just have poor hand circulation which is why they are cold.
It looks darker, and because it is reading the intensity, the label on the can is completely
missing.
If I rub it on my face, the temperature change is immediately noticeable, it’s almost like
painting with temperature, whereas when I rub it on my face without the camera...I just
look like I have a thing for cans.
Thermal cameras are incredibly fun so we are going to do some experiments with it but before
we do, let’s talk about what you are seeing, or should I say, what you aren’t.
The electromagnetic spectrum is the range of all light that exists.
Two of the fundamental properties of light are frequency, the number of waves that pass
by in a second, and then wavelength; the distance from the peak of one wave to the next.
T The less energetic the wave, the longer the wavelength.
The shorter the wavelength, the more energetic the wave.
The most energetic being: gamma rays, x-rays, ultraviolet, and then our small spectrum of
visible light, then things slow down and we have infrared, microwave, and radiowave.
When an object gets hot enough it starts to bleed into the spectrum we see, moving from
infrared to visible.
You can see this with the hot door handle in my video Could You Survive Home Alone.
It becomes incandescent, it hits the Draper Point, 977F, the temperature at which almost
all solid materials glow.
And the infrared spectrum isn’t the only range technology has allowed us to witness.
There are telescopes that can see gamma rays, x-rays, ultraviolet wavelengths, microwave
and radio waves.
And when we see these images, we are seeing false color, a representation of the invisible
spectrum but it doesn’t show what the star, nebula, or solar system would actually looks
like to our naked eye since we are being shown parts of the spectrum we’d never see.
Take this image by the Chandra X-Ray Observatory of the supernova remnant Cassiopeia A. This
is a false color image.
What is actually captured is this….3 images in the soft, medium, and hard x-ray band.
You can even download some raw x-ray files from the Chandra website and create your own
false color composites if you wanna give it a go.
I show how to do it in the latest DONG, do online now guys, episode over on the DONG
channel, link in the description.
Back to Thermal cameras, there is a common misconception that they allow us to see through
objects.
For example if we look at this wall we can see the studs (HOT HOT HOT STUDS), the wooden
beams, that are on the inside, when really we are just seeing the difference in heat
between the wall and the beams.
We can get a glimpse at an object’s emissivity, that is how well an object emits thermal radiation.
A perfect emitter is Black Body, an object which absorbs all light.
It doesn’t reflect it or allow light to pass through.
And similarly to absolute zero, it is something we have yet to witness or achieve.
Let’s try something else...
If I take a mylar blanket, and cover myself with it, you can’t see me anymore because
even though this is a thin plastic sheet, it is heat reflective so I’m hidden.
But if we take a normal plastic sheet like this black square, like this plastic one here,
you can start to see my heat radiate through the object.
Pretty neat!
Now that is pretty cool- But ya know what’s cooler than that?
What’s cooler than that Ian?
Trash.
Garbage The gross stuff.
So Ian this is just actual garbage.
Or is it?
Hey Vsauce, Michael here!
The plastic this bag is made of is opaque to visible light, you can’t see through
it, but it is transparent to infrared light.
The infrared radiation coming off my skin passes right through it into the camera.
Now that’s what I call garbageducational.
Sort of a rubbage pun though.
So as you can see you can’t really see through Michael’s glasses...they look more like
sunglasses.
Pretty Interesting.
Glass acts differently in thermal vision.
Normally if I close this glass door...you can still see me it’s transparent.
But if we open the door and close it again while looking through the thermal camera it
becomes opaque, I’m no longer visible.
And in fact you can see our wonderful cameraman Eric Langlay on the other side.
Glass is designed to pass visible wavelengths and block thermal or infrared for insulation.
Not only that, but just like the Mylar blanket, you’re seeing the reflection of the glass
as well as the window glazing.
Quick side note: If you can’t see glass through a thermal camera, then how can you
see anything since traditionally lenses are made from glass?
Well, that’s because thermal lenses use the element germanium instead of the traditional
glass lens.
So hiding behind a window would be a great way to hide from something with thermal or
infrared vision.
But, the movie Predator tells us that there is another way.
So to recreate the scene in Predator where Arnold Schwarzenegger covers himself in mud
and makes himself invisible to the Predator’s thermal vision we need a few things: three
strapping young man, a bucket full of mud, and Ian shirtless.
I can do that.
But before we begin there are two other things we wanted to show you.
A balloon, but when it is inflated you can see through it.
Hey.
Isn’t that incredible.
Look at that.
And then another fun thing to do, if you wanna “draw with heat”, grab any kind of surface,
in this case the Curiosity Box, and as you can see it is very colorful has images and
stuff but in thermal vision there is nothing there until.
Oh yeah.
That friction is making some heat, I can’t see it though.
But now you can!
It says Inq who is the mascot for the Curiosity Box.
The Curiosity Box by Vsauce, the Best Of box is shipping right now for new subscribers.
It is filled with amazing stuff curated by the Vsauce fellas and it is a great way to
support your brain growth and also to support Alzheimer’s research.
Ok.
Soooo uh...let’s get your clothes off.
Ok, let’s do it.
Do you really want me to get naked right here?
Yup.
Yeah, it’s cool.
You just do you.
Alright.
Well don’t do you, do what we say.
Should the glasses come off?
Yeah take the glasses off.
Maybe put your hair back a little bit.
Whatever you do don’t warn me.
Yeah know I hear when you’re painting a wall you want to sandpaper it before it.
Maybe we coulda done something like that to me.
Is it cold?
Just a touch.
Let’s get ya on the ground.
Alright.
Oh that’s great.
The face we need to cover the face.
Yeah, make sure you do the face.
That is really satisfying slapping the mud on.
We’ll keep an air hole.
Should we get a straw?
Is this like a certified mudbath?
A certified Vsauce mudbath?
So it kind of worked!
Everything covered in this mud mixture is hiding his body temperature and you can see
the parts that aren’t are still radiating.
But it was pretty effective, but that could also be because this is pretty cold right
Ian?
Yeah, it is fairly cold.
This really isn’t very scientific I just wanted to cover Ian in mud so we did it.
So this was a fun experiment right guys?
Yeah, real fun.
Be sure to check out iDubbbzTV it is Ian’s channel.
He is a fantastic young, very young, talent.
Thanks mate.
And, as always, thanks for watching.