| by Kenneth Chase | 100 comments

The rare property of pumpkin seed oil – dichromatism

I’ve got a liquid here with a really rare property It’s pumpkin seed oil, and I put someone a petri dish [so] you can see in more detail [there’s] a thin layer of oil covering the base of the petri dish making it green But when the oil bunches up it turns this beautiful shade of red, and that’s because pumpkin seed oil is Dichromatic and I want to explain what dichromate is ‘m is to do that? I need to explain how color works, and I need to explain how we perceive color and those are quite complex subjects So I’m going to simplify things for this explanation and then at the [end] for anyone who’s interested [I’ll] go into a bit more detail, and I’ll explain the simplifications that I’ve made so first of all how does color work? How do things get their color? Well I’ve made this drink for myself. You’ll see that It’s bright green and the reason we can see this drink at all is because it’s currently being illuminated by white light and you might Know [that] white light is just all the colors of the visual spectrum mixed together and what happens is this drink Absorbs some of that white light but the rest it allows to pass through or transmit, so it absorbs Some of the light, and it transmits the rest But the important thing is the amount of light [that] it transmits and the amount of light that absorbs is Different depending on the color of the light, and I can show you that on a graph. So here we go This is the visual spectrum. This is all the colors that we can see. I haven’t labeled my axes because, uhh, I don’t give a f— Along the bottom is wavelength, So you can see that red light has a [longer] wavelength Than blue light and green light has a wavelength in between and up the side is transmission So, [that’s] how much of each wavelength of light how much of each color of light does the drink transmit So we can show that now. There we go so this drink absorbs most of the blue light it absorbs most of the red light But it transmits most of the green light so we’ve got all this green light passing through the liquid Into our eyes, and that’s why we perceive the drink as green but how do we perceive color at all how do our eyes tell us about the color of the World around us. Well. It’s all to do with these cells that we have at the back of our eyes They’re called cone cells and there are three types [of] cone cells there are cone cells that are sensitive to the red part of [the] [spectrum] cone cells that are sensitive to the green part of the spectrum [and] cone cells that are sensitive to the blue parts of the spectrum so if we’re looking at [something] in the world And it’s red that means there’s loads of red light coming into our eyes that red light is stimulating our red cones They send a message to our brain and that’s how we know we’re looking at something red great But what about pumpkin seed oil pumpkin seed oil has a more complex transmission spectrum. It might look something like this So you [can] see that it absorbs almost all [of] the blue end of the spectrum it Transmits almost all of the green part of the spectrum and the red part of the spectrum, this is the important thing It absorbs most of the red part of the spectrum Except for a thin sliver of red light and it lets a hundred [percent] of that thin sliver Through and if you look at the area of green on this graph that tells you how much light is Stimulating your green cones, and it’s a lot [whereas] the area of the red band here is Small your red cones aren’t getting much stimulation [so] when you look at a thin layer of pumpkin seed oil It appears green so what happens when you pour more of the pumpkin seed oil in and you have a thicker layer well You would expect a thicker layer of pumpkin seed oil to absorb more light and because pumpkin seed oil Absorbs some green light we expect it to absorb more so that green bump should go down But the oil absorbs zero percent of that [thin] [red] [line] it transmits 100% so if you make the layer thicker it still absorbs 0% Meaning a hundred percent of that red light is still transmitted and if you make the layer thick enough that green bump will go down and down and down and down down until all you’re Left with is that thin red line and at that point. You only have red light coming [into] your eyes Stimulating your red cones, and that is why a thick layer of pumpkin seed oil looks red, and that is how dye craft [Ism]. Works so I [promise] that would explain some of the Simplifications that I made in this explanation the first one is that our visual system is more complex than [just] simply having cones for Red [Lights] cones for green lights and cones for blue light [in] Reality the sensitivity of our red cones and our green cones overlap a lot like in this diagram Here your visual system is doing these complex calculations like what’s the difference between the signal coming from the red cones and the green cones but after all those calculations it’s as if you have cones for Red light cones for green lights and cones for blue light the other Simplification that I made is that the transmission spectrum of pumpkin seed oil is more complex It looks like this, so there isn’t that thin band of red? transmission instead the red transmission ramps up towards that end of the spectrum But it’s almost like there’s a thin band because it ramps up Towards the Edge of what we’re able to perceive So it’s like there’s a thin band of red at the edge of our perception, so yes, it’s a bit more complicated But I hope the simplifications weren’t too painful, and I hope you enjoyed the video and I’ll see you next time


Shawn Cormier

Jul 7, 2017, 4:57 am Reply

I really liked this explanation method. Simplified then followed with an in depth description. GG

Ali Hussain

Jul 7, 2017, 11:53 am Reply

I found this property in my decoupage glue and glossy varnish ! the first one turns from White to blue-purple shades and the other from White to reddish orange shades !
Oh dear physics !


Jul 7, 2017, 4:58 pm Reply

Looks just like Iodine in Potassiumiodide solution.


Jul 7, 2017, 12:16 am Reply

Steve you're amazing. I really do one day aspire to be you

Kent VanderVelden

Jul 7, 2017, 6:54 am Reply

Very cool. I have a VIS spectrometer that I'm going to test pumpkin seed with.

Michael Blackshore

Jul 7, 2017, 1:32 pm Reply

Thank you for this! You got a new sub!

Colin Troy

Aug 8, 2017, 3:55 pm Reply

Just a nerdy question, what map is behind you/ where can i grab that, cause that map is dope.

Rishabh Kumar

Aug 8, 2017, 3:14 pm Reply

What are the factors on which light absorbed by a substance depends?


Aug 8, 2017, 7:37 pm Reply

There could have been a piece of green card under the dish. Call me sceptical.

Sandi V

Aug 8, 2017, 7:52 pm Reply

So…would your blue eyes surrounded by red be dichromatic?


Aug 8, 2017, 11:29 am Reply

Your world map on the wall – I thought it was really interesting. Until I realised it makes Africa look tiny, one of the many projections that does injustice to this mighty continent and makes our own world look smaller. 🙁

ginger nut

Sep 9, 2017, 11:46 pm Reply

fuck you and your awesome videos!!!

Stephen Dickens

Sep 9, 2017, 10:47 pm Reply

You know the old saying, there is no such thing as color, at least outside of the eyeball itself that is. Regardless if there are different wave length frequencies of light,,light without the eyeball has no color, its an evolution illusion that has been very useful. By the way no colors that ever enter the eye, if you imagined colors entering the eye,,which is not how it works,,but anyway no color ever makes its its way from the eye to the brain. You dont see color in the eye, the eye actually is not what sees, the brain takes data from the eye, and makes up the lights color based on the wave lengths that hit the back of the eye. Then the brain imagines,,literally imagines, dreams up so to speak, what that data represents, and as it imagines it up,,you then see it,,all in the brain itself, the back of the brain to be more precise,,but it is based on a total brain neural wiring,,which is all designed by evolution. Ill throw in a bit more for those who find such interesting. Did you know the eyeball can not see anything outside of the body. You may say oh but I look across the room and see the table there. But again you can not see anything outside of the human body, its an illusion of sorts. The eye can only see images once and after they have eneterd the eyeball, but never before. So that image of the table that seems to be outside of your body across the room here. Is really an image on the back of the eyeball, you are not seeing images that are outside of the body or outside of the eyeball, thats impossible. And further stranger still, given you now understand that everything you see that seems like it is outside of your body,,is really just an image inside of your body on the back of the eyeball. The eyeball is not even where you really see something at or from. Im getting technical perhaps here but if you get past the illusions of the senses and how they work, you can better understand even reality itself. So the palce you actually see something is inside of the brain and by the way no light images ever travel from the back of the eye to the brain. Only electrical impulses travel from the eye to the brain, and these impulses have no light images in them. So the brain then according to its genetics, according to evolution,,imagines up the image that the data from the eye represents,,yes the data represents the image, but not literally. But evolution has chosen what data will represent what images that the brain imagines it is seeing,,and the brain imagines it is seeing these images as if they were outside of the body itself. But you are seeing the image the brain imagines it is seeing based on the eyes data, all within the brain itself, like a virtual recreation of reality,,and it literally is virtual in the brain, regardless if that virtual recreation or virtual reality is based on and created by real data that came from outside of the body. Now you know a bit about what and where reality really is and is experienced from. enjoy!

Oskar Elek

Sep 9, 2017, 5:49 pm Reply

Instead of labeling the axes he axed the labels.

Dylan Parker

Oct 10, 2017, 4:05 am Reply

wasn't the horizontal axis of your graph frequency, rather than wavelength?

if not, you are a monster

Mr. Sean Bean

Nov 11, 2017, 5:03 pm Reply

its freaking PEE-tree not PEH-tree

Raul Visnitchi

Dec 12, 2017, 9:01 pm Reply

You forgot about yellow.


Jan 1, 2018, 5:21 am Reply

Interesting. I bought Swanson pumpkin seed oil capsules. When I cut it open, the oil was just yellow… It didn't seem to show any dichromatism… I wonder why? Maybe I should buy another brand of pumpkin seed oil capsule and compare them

nAZ klX

Jan 1, 2018, 9:28 pm Reply

Your eyes are so beautiful

Lily Hambling

Feb 2, 2018, 12:21 pm Reply

looks like Steve had a few cone cells before filming this.


Feb 2, 2018, 12:15 am Reply

i dont give a f
Steve Mould, echoin the sentiments of most students ever…

Alwin Priven

May 5, 2018, 11:54 pm Reply

it looks more yellow though


May 5, 2018, 8:56 pm Reply

1:35, somehow this looks like the french flag

Zulfiqar Ali

Jun 6, 2018, 8:36 pm Reply

Organic Pumpkin seed oil,a wonderful health food supplement, every health conscious person to have one

Tomas Sarabia

Jul 7, 2018, 2:23 am Reply

I like being given a basic concept and then the details to fit the specific case. I enjoy this channel.


Jul 7, 2018, 7:21 pm Reply

This same property is seen in silicone grease.

f. g0nc9lv3s

Sep 9, 2018, 5:00 pm Reply

i know olive oil does this, cant find proof for pumpkin, is it supposed to coagulate in the cold? my gel caps have small white deposits, they are hardened on touch, i bled one, its lump or clump like.

Rohan Sharma

Sep 9, 2018, 8:50 am Reply

Anyone else catch how captions said "dye craft ism" instead of "dichromatism" near the end of the video? I wonder if that was hinting at something…..


Dec 12, 2018, 5:32 pm Reply

https://www.imdb.com/title/tt0120863/ 😀

Dakota Martin

Dec 12, 2018, 2:00 am Reply

It looks very yellow to me.. is that his camera doing weird things or is it me / my screen? I've viewed this video on both an LCD and an OLED screen and it seems yellow.

Josh Campbell

Dec 12, 2018, 12:51 am Reply

Awesome video but dang I was hoping for a how. As in how the pumpkin seed is actually dichromatic. Time to break out the Google machine.

Tom 1851

Dec 12, 2018, 6:18 pm Reply

I’m a deuteranope (red green colourblind)
So this video is going to be boring

Jorge C. M.

Jan 1, 2019, 10:48 pm Reply

in the desc:

Keith Reynolds

Jan 1, 2019, 2:42 pm Reply

"Cause i don't give a…." insert… "fffrequency of light is represent by color on the graph."


Feb 2, 2019, 4:44 pm Reply

Because I don't give a fu-


Feb 2, 2019, 4:55 am Reply

So, how do eyes convert photons into percieved color. Or how do specific wavelengths convert to perceived color?


Mar 3, 2019, 1:11 am Reply

It's also delicious, btw.

Henry McCausland

Mar 3, 2019, 7:41 pm Reply

is it me or are your eyes grey, which is cool af btw

first last

Mar 3, 2019, 4:05 am Reply

It looks yellow and not green on the video.

krishnaa balaji

Mar 3, 2019, 4:17 pm Reply

I thought this had something to thin layer reflection of light.

Tom Collier

Mar 3, 2019, 3:29 pm Reply

cone cells? you mean cryptochromes? red, do you mean rarefaction, or red-shift? I'm guessing rarefaction. But, I'm confused. I feel uneducated.

leonardo f

Apr 4, 2019, 6:12 am Reply

I wonder if making a 700nm layer would make it look perfectly lime green

Rex Monssel Espejo

May 5, 2019, 1:56 pm Reply

i just bought pumpkin seed oil in lazada. The brand is Swanson and it is color yellow. Does it mean its fake?

not amouse

May 5, 2019, 5:34 am Reply

Interestingly, this behavior is also present in the mineral Alexandrite.

Danilo Mancini

May 5, 2019, 7:13 pm Reply

This is the first time I've seen you "swearing" and even though I didn't laugh, it was funny as fu-

Julia K

May 5, 2019, 3:54 pm Reply

What I learned in this video: label your axes with "I don't give a f*ck" ?
Just kidding, great video, as always ?

Risto Pöhö

Jun 6, 2019, 8:17 am Reply

No it isn't changing colors. It just isn't.
Oh. Right. I'm colorblind. Not much but some shades just are the same. It's funny when something is this similar in shades 😀

Nara49 Veera

Jun 6, 2019, 2:36 am Reply


Meg.A. Byte

Jun 6, 2019, 11:59 pm Reply

Thumbs up for not including purple in the light spectrum, I've seen it many times before and I'm glad you got it right.

Joshua Harrison

Jun 6, 2019, 8:05 am Reply

clean you're nose. Lots of bats in that cave


Jun 6, 2019, 9:30 am Reply

Transmit or reflect?


Jun 6, 2019, 5:41 am Reply

I live in the world’s center of original pumpkin oil ( Styria, Austria) basically grew up on that stuff, have it in my fridge right now and never noticed! Thanks for that recommendation YouTube, thanks for the eye opening explanation dear Youtuber, very cool, enjoyed it very much!

Marcin R

Jun 6, 2019, 4:00 am Reply

Your glass does not transmit (create) lite, it reflects light 🙂 …If this is wrong, please correct me and explain why 🙂


Jun 6, 2019, 9:29 pm Reply

4:06 Awesome movie!

Patricio Contreras

Jun 6, 2019, 6:57 pm Reply

Chek out 1:25 … the secret behind the scenes


Jun 6, 2019, 8:15 pm Reply

what would we see under different filters? as UV or UV camera 🙂

River Chadwick

Jul 7, 2019, 3:46 am Reply

Is this actually green? On my screen it looks golden fading into red at the pooling points. It doesn’t appear green at all, like your “drink”


Jul 7, 2019, 6:08 am Reply

Thats yellow


Jul 7, 2019, 3:37 pm Reply

But isn't all color created inside the brain? I mean the color itself, not the difference between the colors we see.

Ronaldo Brito Roque

Jul 7, 2019, 6:32 pm Reply

How can you make a mirror that reflects light in black and white?


Jul 7, 2019, 10:36 pm Reply

It looks all red on camera

Jean Mercat

Jul 7, 2019, 6:13 am Reply

This is not really accurate, there is reflected light, absorbed light and light that passes through. For example if you dilute milk you can check that it reflects almost all colors but it lets red light through

Aryansh Sharma

Jul 7, 2019, 11:29 am Reply

It aint green it’s chlorine colour


Jul 7, 2019, 11:43 am Reply

could you list your sources?

Bilakshan Purohit

Jul 7, 2019, 1:58 pm Reply

I got it bro I got it!!


Jul 7, 2019, 2:13 pm Reply

Is that how blue skies / red sunsets work?

V King

Jul 7, 2019, 9:15 pm Reply

i have'nt labeled my axes coz i don't give a f

Santhosh Janardhanan

Jul 7, 2019, 2:12 am Reply

Steve, audio in your videos is having too much treble which makes your 's' s sound like whistling. Making the video tough to watch. Can you adjust this in future videos? I don't want to lose the great knowledge you are sharing.


Jul 7, 2019, 12:18 pm Reply

Is it the same with those pigments for mixing diluted paint? I have some Fluorescein pigments here, in their bag they appear more orange-brown, but when diluted the color become the typical text marker florescent green. Same for the Rhodamin pigments, they appear shiny green in their bag, but when diluted, the color is a very nice and bright pink! I am not a chemist, but still, the physics/chemistry behind those pigments fascinated me since I first saw them….


Jul 7, 2019, 4:30 pm Reply

Those red eyes
Ain't fooling me he's high

Adarsha Hegade

Jul 7, 2019, 5:53 pm Reply


Jeffery Wells

Jul 7, 2019, 6:58 pm Reply

I've never failed a color blindness test, but that oil looks yellow and red to me, not green and red. Just little flashes of green at the corners of the petri dish. And I see the green water and the full spectrum just fine.

Sven Yolanski

Jul 7, 2019, 7:24 am Reply

Hey, why didn't you label those axes, again?

Dominic Surette

Jul 7, 2019, 3:35 am Reply

Some say to this day he still doesn't give a fu-

Ethan Jones

Jul 7, 2019, 5:57 am Reply

dichromatic is sort of like when your moms black and your dads white and you got pale skin but grow a black afro. you feel?

Kevlar Canuck

Jul 7, 2019, 10:19 pm Reply

I indeed learned something today ?

Marcelo Monnerat

Jul 7, 2019, 1:01 am Reply

Can i dye my car that color?!

Orville Canter

Jul 7, 2019, 1:13 am Reply

how does one determine what the transmission spectrum looks like?

Isaac Dueck

Jul 7, 2019, 1:18 pm Reply

A solution. Of water and potassium hexacyanoferrate

Isaac Dueck

Jul 7, 2019, 1:18 pm Reply

Is also diachromatic

Sardi Pax

Jul 7, 2019, 1:48 pm Reply

An interesting application for that oil might be to visualise the propagation of sound waves, with such a high contrast between different thicknesses.


Jul 7, 2019, 5:29 pm Reply

But what explains color on a molecular level?


Jul 7, 2019, 8:58 pm Reply

More like dyechromatic

donal reilly

Jul 7, 2019, 12:20 am Reply

"I haven't labelled my axes because aaaaah I don't give a f-"
Steve Mould 2016


Jul 7, 2019, 2:11 am Reply

0% red light? That means you can get a thousand gallon in a tank, and it won't look black?
I don't believe that.
The numbers might be more like absorbs 10-20% of red light. Not 0%.

Also, they usually put red on the left in a graph, because the wave length is longer, and blue on the left.
You're basically telling us with this that the oil will be emanating infra-red, in other words, it'll absorb UV and color, and re-emit red and infra red (heat) instead.

The General

Jul 7, 2019, 3:08 pm Reply

Someone's had a doobie or two me thinks…..??

Ady Day

Jul 7, 2019, 12:10 am Reply

So much easier when explained simply…some professor with medals would of told it using a calculator hahaha…and converted it into an health and safety policy involving licensing and qualifications to open the lid ?


Jul 7, 2019, 3:50 am Reply

Is this effect the same reason some fountain pen inks have a "sheen" property? This is where the ink will appear a different color at certain angles to the light, especially when on certain "ink resistant" paper and where the ink color has pooled a bit more in the letters.


Jul 7, 2019, 12:18 pm Reply

It would be interesting to see this combined with a standing wave setup. You'd get static red/green zones at the nodes and flashes between the two at the anti-nodes if you got the depth right.

jitendra nayak

Jul 7, 2019, 2:13 pm Reply

Have u slept properly? I feel like u haven't for last 1month….or may be u hve a plan to become a VAMPIRE….oooo

Chathuranga Hettiarachchi

Jul 7, 2019, 12:59 am Reply

Hmm . Ever heard of something called Reflection.. ?


Jul 7, 2019, 8:43 am Reply

Love the not giving a f part!


Jul 7, 2019, 6:51 pm Reply

Des is oba ka steirisches Kernöl. Pfui! 😀

Kushagar Sudan

Jul 7, 2019, 1:43 pm Reply



Jul 7, 2019, 6:10 pm Reply


Cassidy Mugadza

Jul 7, 2019, 6:15 pm Reply

Tell them that you just don't give a F##k ?????

Emilio Marranzino

Jul 7, 2019, 4:32 pm Reply

It’s pronounced (pee-tree dish)

Michael M

Aug 8, 2019, 1:21 am Reply

doesn't the colors also come from reflections (and stimulated emissions)?

aXel Red

Sep 9, 2019, 2:21 am Reply

what in the fuck are those eyes, it's like orange clown makeup.

Mass Debater

Oct 10, 2019, 1:57 pm Reply

My car does that but it's called a chromatic wrap is there a difference? Also my rims change colour for heat cold and liquid what's that called and how does it work?

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