Can You See Me?

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.

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