What is Infrared Light? William Herschel's Amazing Discovery of Infrared Radiation and Waves - 02

What is infrared light? Here we will learn the story of William Herschel and how he completely by accident discovered infrared light. Infrared Radiation (IR) was unknown in his time, but now we know that the IR spectrum is just a small part of the broader electromagnetic spectrum.
Herschel discovered infrared radiation by measuring the temperature of different parts of the visible light spectrum made by passing sunlight through a prism. He discovered that just beyond the red part of the spectrum were invisible infrared waves. Now we know that the definition of infrared light is just longer wavelength waves in the EM spectrum. We also now know that infrared rays are associated with heat and that the infrared frequency range is just beyond that of the red light in the visible rainbow.
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Hello welcome to smarter in
science we're going to take a few
minutes of your time and learn together
about something truly amazing in the
realm of science.
Today we're going to
talk about the amazing discovery of
infrared radiation. There's a really cool
story behind infrared radiation and how
it was discovered i'm going to share
that with you today.
The first thing is let's talk a little
bit about what is infrared radiation and
that is basically the type of light in
type of invisible light that we
associate with heat is given off by an
object. so here are a couple of examples
of that here's a space shuttle that's
just coming from the atmosphere it's
gotten very very hot
notice the underside of the ship is kind
of as the reddish colors and the whitest
the whitish color is where the top of
the ship is blue bullish colors.
so what
this means obviously the bottom of the
ship hotter and when something is hotter
it radiates more infrared radiation and
so those why the coat that's why the
colors are red there where is the top of
the ship is not as hot and in this
picture is represented by blue because
it's not radiating as much in the
infrared there on the top of the ship.
here's a picture of a house and you can
see sort of the same thing here most of
the house for instance the the the roof
here is a bluish color that means that
there's not very much heat coming out of
the roof there it's nicely insulated
there but the ridgeline here at the top
of the house the windows the doors
things like that it's very hard to
insulate those so you see the heat coming
through the windows and the doors and
that's why you see the red there because
the heats coming from the inside of the
house out you see that in the infrared.
Ok
as I said before the discovery of how
this radiation behaves and how it was
discovered two stories really really
neat and we're going to talk about that
right now.
So I'd like to introduce you
to somebody if you've never heard of him
he's a famous scientist whose name's
William Herschel lived from 1738 1822. Now
this picture of our sun is a modern
picture of course Herschel never saw the
Sun as it is in this picture here from
this from a high-powered telescope or
satellite as we see it today.
Basically he spent a great deal of time
studying light from the stars with the
telescope that he used in his day and
what he did one of the things he did was
he was put these filters in front of the
telescope different color filters.
red
filters yellow filters blue filters to a
basically filter the light coming from
the Sun so that he could study in his
telescope and just from the interaction
with the telescope he started to realize
that he thought the red light from the
Sun when he would isolate the red light
seemed to be hotter than the other
colors as he would isolate them with his
filters now this wasn't a scientific
experiment this was just something he
was noticing so he decided to
investigate further.
now even back in Herschel today the
scientists of the time were well aware
that sunlight can be broken down with
composed of a whole host of colors of
the rainbow there and he knew all about
prisms that could do that job.
So he knew
that sunlight was a mixture of all the
colors of the rainbow and he knew that
he could take white light and split it
up into the different colors
violet indigo blue green yellow orange
and red so what he wanted to do with
scientifically see if any of these
colors coming from the Sun actually had
a higher temperature or did they all
behave the same.
So in order to do that
he decided to set up an actual
experiment to test and see if they were
all the same or any of the colors were
hotter or colder than any of the other
ones. now here's what we have a sort of
an artist rendition of him of a personal
in his laboratory and you can see the
sunlight coming in being split by the
prism and form a rainbow down here now.
in 1800 he devised his experiment to see
if the different colors of the rainbow
actually had different temperatures, and along the way he
completely by accident discovered infrared light.

[@zeqi]

Can we also appreciate how he typed everything he said in the description?

[@ChristOMalley]

why should we appreciate this over anything else ? you dont know if he typed it or copy and pasted it and this leads to why why are you saying this? im truly curious

[@l.clevelandmajor9931]

One thing you failed to point out is the fact that it is not the light that is hot, it is the object that emits the light that is hot. When Herschel did his experiments, he was not measuring the heat of the light itself. rather he was measuring the heat of its source; in this case the Sun. He may not have understood this at the time, but the hotter an emitting object is the more light it emits, as the light grows in intensity it's infrared light does as well. The more intense the infrared light is, the more it will heat a blackened surface. A true black surface would absorb all light and re-emit it as infrared light. all other light gets converted to heat in this absorption, so the brighter a light source is, the hotter the absorbing surface will become. In case you don't know this, even the other wavelengths of light caused the temperature of the thermometers they were hitting to rise. So in white light you have to know that the temperature of an emitting source is a combined temperature caused by all the light being emitted.

[@SunShine-kd6td]

The prism impedes the sunlight, therefore it is cooler than the ambient light.

[@altoid4820]

shut the fuck up

[@slooob23]

If infrared light is of a lower energy part of the wave length, why is it hotter than visible light? I can't understand why the temp drops as the wavelength becomes more energetic.

[@l.clevelandmajor9931]

@@slooob23 Simple really, the more energetic something is, the quicker it can be converted to light and escape its source. A surface that can absorb light energy will absorb the infrared light first, as it is the easiest to absorb. So that surface will continue to increase in temperature so long as it can contain the generated heat. When it reaches its own temperature limit, the stored energy will cause one or more events to happen to that surface, and the release of energy will be one of those things, in the form of mostly infrared light.

[@mosh6292]

This really helped me with my reporting, it really made me understand and enabled me to ellaborate it more to my teacher and classmates which resulted to good grades

[@realizanatividad7958]

me too haha

[@veenarao761]

I don't even know how 10 minutes 58 seconds went really awesome sir 🙂

[@barlizoprincessann_0631]

This channel is a life saver, been watching your videos since I was like in grade 4 or 5 🤞

[@nitinsuryawanshi2147]

that's a great explanation👌👌but i have a question i.e. red colour waves have more wavelength , less frequency and hence less energy than violet colour then how it is more warmer than violet??

[@deniscandido4116]

I'm tired seeing this error on the internet.... Even on khan academy they're commiting this error

[@andres-vi1uy]

the higher the frequency more energy but energy doesn't necessarily mean heat, take microwaves for example even a higher wavelength then IR and it's possible to warm up food when the source is strong enough or you can share information between devices with microwaves it's just a matter of how you use it

[@andres-vi1uy]

there'd a reason ir is known as heat rays...

[@jeanie51156]

this was a very interesting presentation, thanks for enlightening me! I would like to understand the healthful aspects of infrared better.

[@FreeCandyGuy]

So considering that infrared is beyond the visible light spectrum yet can be split by a prism, does this mean that gamma rays, x-rays, microwaves, and radio waves are also split like the light we can see? Is there a band of microwaves just beyond the band of infrared light?

[@user-in4sg1nt4t]

I enjoyed this a lot ..nice job plz post more videos on inventions...regards and love from India😃👌👌

[@MathAndScience]

Thank you very much, and I will!

[@cheesecakegaming6056]

Are u subscribed to PewDiePie or t-series??????????????????

[@ren23030]

@@cheesecakegaming6056 How immature.Do you ask that to anyone who mentions india 🤣🤣

[@ovechkin100]

Jason Gibson is the ultimate nerd. But the type of nerd that makes us all envious of nerds, and wanting to become one ourselves.

[@MathAndScience]

Nerds unite! Thanks so much!

[@Fireraidz]

Good stuff here my dude

[@fusion9619]

2 things I don't understand: - why are lower energy wavelengths hotter? Seems like lower energy should be cooler. - what actually causes hot objects to emit infrared radiation?

[@cookwiththecook1343]

1. Wavelength invervesely proportional to energy the lower the wavelength the more energy it would have . 2.The more hotter the body is the more the electrons excite and When the electron transits from an excited state to its lower energy state, it will give off the same amount of energy needed to raise to that level. This emitted energy is a photon.so the more hotter the object the more it emits . Im not exactly sure this is 100% correct

[@fusion9619]

@@cookwiththecook1343 sounds right. Thanks!

[@cookwiththecook1343]

@@fusion9619 no probs

[@cookwiththecook1343]

Sorry for late reply ✌️

[@billminckler6550]

How insightful and cause for appreciation and reflection (pun intended). Thank you!!! 👏

[@georgezama]

If you don't mind me asking, how are infrared bulbs made/produced? Thank you very much for uploading this video! Kind regards, Dan George

[@thekeithchannel]

These videos are awesome. One thing that confuses me is if energy density increases as you move towards ultraviolet, why does temperature increase as you move towards infrared? Also wouldn't that mean that radio waves should burn us, or does that heat energy fall off somewhere? I might lose some sleep over this one XD

[@MathAndScience]

This is an excellent question and I was struggling with if I should include it in the video. The short answer is that the sun doesn't blast out all wavelengths equally. Take a look at this: en.wikipedia.org/wiki/Sunlight#/media/File:Solar_spectrum_en.svg Notice that the peak is in the visible. UV falls off dramatically. Infrared is huge and is the bulk of the tail. You should be looking at the area under the curve here. So, each individual photon of UV carries more energy than each photon of infrared, but the sun sends out a LOT more infrared photons (or waves if you prefer to think about waves). So, the thermometer is getting more infrared radiation hitting it because more IR photons are hitting it. Another factor is that our atmosphere blocks most UV so most of it never reaches the ground anyway, while a good deal of the visible and infrared comes through. Hope this helps! Really great question.

[@thekeithchannel]

Oh okay that makes a lot of sense. Thanks for the answer and the quick response. Looks like I won't lose sleep after all

[@tal3054]

@@MathAndScience Yeah but below infrared is microwaves right? So I'm saying why microwave heat so much if there is so little energy in them. I would really like to know it really bothers me. Lol. Sorry for my bad English it is my second language.

[@karenvickery6070]

And blue flame is hotter than red flame.

[@leefletcher4163]

ツTalツ I think we have a hard time understanding the intensity/brightness of wavelengths outside of the visible spectrum. The heating of the food is caused by the intensity/volume/brightness of the microwaves ie the number of photons hitting the food per second. You could heat the food with other spectrums of light if you hit it with a comparable intensity of that light. For example, a consumer microwave can use 1000 watts of electricity. If you put a 1000watt light bulb in the box, it would also heat the food quickly. The reason we use microwaves is not that they have more energy to heat food. It is because the microwaves can penetrate about 1cm into the food and heat it from the inside. This allows you to heat the food quickly without burning the outside of the food. Also the microwaves are easily contained within a thin metal cage. See Faraday cage. This allows easy energy/heat containment. Which is important for avoiding fires. Can you imagine how hot a 1000W bulb would get? Most of that energy would go out into the environment and would not be captured by the food. I hope this helps someone. I found it a confusing subject as well.

[@jsc3417]

Why then in terms of color temperature, the blue color has higher temperature in K than the red color?

[@iDhanasekar]

Thanks a lot for the video. Thumbs up

[@hermanloud3098]

I have a feeling that in the future (if we make it that far) science will feel like magic, and magic and science will be synonyms, I know it sounds stupid, sorry to dare, but for me the radio, WI-fi and electricity are amazing discoveries, imagine you can time travel to middle ages and explain how you can communicate to another person without any kind of cable, you will be considered a witch. "What other aspects of our universe are we ignorant of just because we can't see it and haven't blindly stumbled upon it yet?"

[@vibewithkaey4269]

tbh i love the way u explain its really easy to follow up

[@StevenNehr]

everything will be much easier to detect once we keep going beyond the gamma rays and radio waves.

[@zafreiamirul]

good point

[@abigailrico5892]

Thank you so much

[@alicekichlu215]

THE CHART OR,GRAPH IS BACKWARDS BUT,EXCELLENT EXPLANATION.

[@influenza99]

I have trouble understanding why infrared is hotter than ultraviolet, given the fact ultraviolet is packing way more energy?

[@therealOssie]

@influenz99 Hi, I’ll try! A photon of Ultraviolet radiation has a lot more energy than a photon of Infrared, but the total energy has to take into account the number of photons as well. Whats a photon?, its particle representing a quantum of light or other electromagnetic radiation, I hope this helps. Cheers

[@tomc642]

@@therealOssie Interesting. In short, are you saying that a source of infrared light emits more photons than a source of ultraviolet light?

[@dzl4546]

Thank you so much for this video

[@squeezedce6115]

Thank you for your effort and time Your channel is worth watching

[@kennythelenny6819]

How or why is infrared light hotter than visible light when it has a longer wavelength and lower energy than visible light?

[@slooob23]

Exactly, this is annoying me too. The only thing I can think of is that maybe infrared is more efficiently absorbed by a surface while a large portion of visible light energy is reflected.

[@justuskalungu6111]

Fantastic content but You should have a search engine for your videos. They are so many at finding a specific video is not easy. I have tried to search on integrals and basic maths, sets no success.

[@jass5g]

Great video!

[@johnnyrottensr.6549]

Great topic! How many things are we looking at and not seeing. Transients are plentiful on this planet but humans being the knuckle dragging cavemen that we are usually veiw them as a disadvantage. For instance lets say water hammer. Some see it as a shaking noise making menace that sometimes ruins systems designed to hold or distribute liquids. We will design ways of stopping it instead of applying it as a means of pumping the liquids higher and more efficiently than other methods. How can so many intelligent individuals have absolutely no idea of the what and how that is responsible for everything we see?

[@robertstover4665]

Great information!

[@primaryeducation5500]

Nice explanation,thanks

[@lillchamps6998]

Thanks Sir..I really enjoyed a lot...It was quite informative 😊😊

[@michbest]

The aliens can be among us. We just dont see them ;) Thanks for the explanation. Great job! 👍

[@johntokarski7487]

Great demo Thanks

[@tonysantos6345]

How can it carry less energy and yet be hotter?

[@Qusaabuomar]

Thanks that was a great explanation

[@gambart2002]

awesome explanation thanks

[@dariusz84]

Ridge line is probably hot because it's not vented not necessarily to do with insulation.

[@Aisha-gd6dq]

Thank you so much :)) ))

[@sukhadavelankar7404]

nice explanation sir

[@shirintabei3301]

Thank you!!

[@godarmy3674]

This really help me to prepare for my exams🤔🤔

[@MathAndScience]

I really appreciate it! Jason, MathAndScience.com

[@lorenzomonreal5590]

How can energy be present on both ends of the spectrum? Violet contains the lowest heat signature...but gamma ray is a concern for our health? What am i missing?

[@asmaaal-ani5904]

wow i love it. Thanks a lot. By the way i think the first picture was an airplane not a ship.

[@SunShine-kd6td]

The air that is not impeded by the prism is, naturally going to be warmer. Like our skin, submerged in pool water is cooler than that above the surface.

[@2lb_slat]

Love from india

[@richardpaulson8954]

So please explain why the sky is blue and not violet should it not be violet? Why is this info classified?

[@h25tv4]

Nice Video....

[@LostFunocity]

The stuff you find on the internet. Mind blown of AWE

[@josiahhood7000]

Thanks

[@Xerkies]

IR light is not always giving off from heat.

[@erikamilaya7971]

MODULE BROUGHT ME HERE"

[@wasleedbroskie3490]

Is this statement true or false? At a cold front, cold air quickly pushes under warm air, causing strong winds and precipitation -- often thunderstorms.

[@karenvickery6070]

But blue flames are hot than red flames. It’s a fact when fire changes colour from red to orange to yellow to blue it gets hotter, so blue is hotter than red. And how did they tap into infrared, how do they make it?

[@dooomskick5345]

@DFM it doesnt matter if the red stars burn longer than blue stars. Her point is why red is hotter than blue because blue stars are way more hotter than red star

[@bookmaster3699]

Such a good video!!!💣💪🏼👈

[@MathAndScience]

I really appreciate it! Get our Free App and View all Lessons! www.MathTutorApp.com

[@gyro5d]

What about Aether, Counterspace and the Inertial plane?

[@catrukha5156]

How can infra red light be detected is there any device which could detect infra red?

[@toby9999]

Lots of things, even your skin. Night vision goggles?

[@dadakhalindar7149]

Do any one know the methods to record infrared frequency

[@Lurch-11]

Him having the extra thermometer wasnt an accident lmao it was a control.. basically the exact opposite of an accident.

[@shubhamsharma3366]

This is fukin amazing Thanks for this video!!!!!!!!❤❤

[@user-jg7ki4ml8w]

Hello how can I communication with you

[@sparkimooo]

Awesome ;o

[@Aladinscave]

Well hopefully with the James Web telescope we will be able to see a whole lot more…

[@thebestofallworlds187]

10:20 we've already learned everything.

[@drdoctorandrews437]

No

[@chaoticstorm8145]

Were farrrrr from knowing everything buddy

[@darrend267]

what does the prefix infra mean

[@shitpostvlogs2308]

Darren D below

[@ItsCurd]

When it's not on a color. Wouldn't that color be black.

[@jamesworley7033]

why would red be hotter then violet if violet is higher in energy''?

[@ijikayuto2950]

James worley it is magnetic and electric photon waves

[@solaris5524]

skuyla na ian

[@abhayagarwal5097]

@@solaris5524 english

[@pecador_tor]

Yoooo wasnt this on cosmos

[@user-pb4jg2dh4w]

How can violet be colder then red, we all know that violet has more enrgy than red 😵😵😵😵😵😵😵😵😵💫💫💫????????????????????!!?!?!?!???

[@itwilsonboiii4789]

how infared hotter than visible light

[@itzpez3447]

I can see infrared a little bit. I need to be in a very dark room to see it.

[@josiahhood7000]

9:47 - Jesus, God, heven, hell, angels, demons, and the holy Spirit

[@richardpaulson8954]

So microwaves aligned or phased together form a kind of laser in that spectrum, is that radar? And how do we form laser radar. Explain acousto-opitcal cells and laser radar