I have had one of my eyes' lenses replaced with an artificial one (cataract surgery) and I can definitely confirm being able to see slightly farther into UV in that eye. It's nice having only one of them removed because I can compare between the two eyes.
***** Horrible misinformation is a bit harsh, although, to some extent yes, it is pretty awful. The fact is you won't get enough vit D from foodstuff alone, and so the sun is essential to get enough. It's not in A LOT of food though... It's more like a middle ground between your statement and the video's.
NorwegianQvirr I kind of agree that is horribly misinformed when it suppose to be a factual video. This is also such a old myth that most people should know better nowday
Recently, I purchased a U.V. flashlight and never really understood how it worked, and this video explains more about U.V. light. I really wish you'd show more household items and explain why they react U.V. light they do. Really enjoyed this video!
Interesting to watch the ghosting at around 3:20 mark, looks like a nice display of the image stabilisation element(s) of the lens at work perhaps? (24-105 IS, Brady?) Aside from this, another great video, Dr Meghan always explains ideas succinctly :)
Excellent video and a very good idea for a series of videos!! I would have liked to see more on UV absorption though. As an astronomer, it might not be the first thing on your mind. But for the general public, UV absorption of sunglasses, windows, sunscreen etc. is incredibly important.
The highest frequency of visible light is roughly twice that of the lowest freq. of visible light, making the 7 colours of visible light (like the 7 notes of the diatonic scale) basically an octave. We hear the resonance of a high C and a middle C and a low C. Were we able to see beyond the visible spectrum, would we see the resonance of hyper red and red? . (BTW,... How you were able to resist lava lamps and wakachicka music I'll never know!..)
Glad to see Dr Gray back on Sixty Symbols. I assume she is still a regular face on Deep Sky...though I have to admit I have not wandered over to that channel in a long while. Something I will have to remedy (after I watch this one of course).
The only perfect conductor is a superconductor, and inside those light pretty much doesn't propagate. Or rather, it can be described as gaining a mass.
Jesse Mason The EM Field is never "not there"; even at zero energy in the EM Field it is still present. In fact it cannot reach zero energy because of natural Quantum Uncertainty, we can't ever be sure a field has reached zero energy because there could be ± some energy in the field (uncertainty). The EM Field therefore does exist everywhere at all times: inside conductors, super-conductors, and even inside black holes!
We happen to now understand that the classical picture is wrong. You seem like a smart guy, why would you use a wrong model of reality? There is only one kind of light (not many forms with one being "normal light"), that comes in packets called Photons with varying wavelengths [color] and energies. Metals are typically opaque and shiny for other QM reasons (see photo-electric effect, etc.); not all metals are totally opaque, not all metals are shiny.
Rob Laquiere Because it can work as a well enough for the situation you care about. Do you care about the coriolis force when throwing a ball out for a dog?
I suppose I don't, but the fact remains that it is still there. I do typically leave out insignificant effects when doing calculations so you are right.
So glad I watched this. I had never seen fluorescence demonstrated like that and I think the combination of the visual with the explanation that the energy it emits is lower because it loses some brought it together for me. Thanks!
That is a telescope image, so technically yes. But viewing it with just your own eyes, it would be far too dim to see those details. As for rotation - absolutely not. Think about it. It's 220,000 light years in diameter, a single pixel in that image is as large as thousands of entire solar systems. The period to rotate one revolution is anywhere from tens of millions to hundreds of millions of years.
Hugo Santos Indeed! And that's why Astronomy is such a humbling activity :) It should be noted that we can actually measure the rotation of the Andromeda galaxy, even if we can't see it happening directly. So we do know it rotates, just like our own galaxy.
Hugo Santos no you cannot actually see the rotation when looking at a galaxy it is way too large to notice any change in position at the small timescale that humans use.
Interesting video. Makes me want to reassemble my TEA laser and fire it through some fresh olive oil and mint and try it on various fresh leafs. It'd be neat to see the red.
Is there a limit to how short and how long a wavelength can be? I would assume shortest possible wavelength is close or equals planck length, while longest possibke wavelength is only limited by the size of the universe 😊
I remembered Quinine emit longer wave length is light because the electrons jump up several energy levels when they absorb UV photons, then jump down one energy level at a time and emitting lower energy photons.
Will you guys be covering more of the electromagnetic spectrum? I'd really like to learn the basics about wifi-signals, microwaves, bluetooth etc. and how they relate to easy reception/amount of data that can be transferred etc.
Can you tell the purity of olive oil with the black light? Just asking because some companies mix other oils (canola) in with the olive oil claiming it to be 100% pure.
When a photon of UV light is absorbed and an electron is excited to a higher energy level, surely the energy gap between the electron and the ground state is the same. The electron cannot lose that energy in different stages as energy levels are discrete, so why is the emitted photon not the same wavelength as the incoming one?
how can i ask bradys physicist buddies a question? i saw a vid of a guy burning sea water with radio waves. were just the impurities in the sea water burning?
The pre-roll ad won't leave the screen. Its done and now it won't go away - just frozen on the last image. So I can't watch the vid. I've gotten out and reopened the video twice and it plays the pre-roll commercial for 1800 contacts and then stops.
I can't help but wonder if the range of colors we see is by chance. It happened to be the most useful range for random attributes that previously made no difference to evolution, but once an efficient range was found for those random attributes, evolution was bound to them. It makes me wonder if we do discover alien life, if they would even see in the same color range as us. Maybe they will be gray because their actual color is outside of our vision range.
If the olive oil with chlorophyll emits red light, it means that when those electrons are excited, it loses MORE energy than that of the electrons in the tonic water. So my question is, what factors of the molecules determine how much energy the electrons lose after the photon is "absorbed". What makes the electrons in the olive oil lose more energy than tonic water, thus emitting a visible light at a lower frequency?
It's just the difference between the excited state, having absorbed a UV photon, and the next lowest state. In the case of olive oil it is not a large difference. So say the energy goes from 0 to 1 during absorption. It may only go from 1 to 0.8 during emission. If you want to know more it might be worth doing some research on the chlorophyll molecule, what atoms it's made up of and what energy level the various electron shells are at.
+SOEL86 it doesn't have to be the next lowest state, in fact, there is a rule in quantum mechanics, known as Kasha's Rule. most (over 99.99%) of transition to the ground always take place from the lowest vibrational state of the first excited state, to one of the vibrational states of the ground state. you can excite a molecules to any of its higher excited states, but it will usually undergo vibrational relaxation and/or internal conversion or intersystem crossover to another spin system, regardless, it will always undergo vibrational relaxations by colliding with other molecules and only emit a visible/NIR photon from the first excited state.
sidewaysfcs0718 Ah yes thank you. It was off the top of my head and I knew there was something wrong. So the difference in colour emitted depends on the nature of the molecule, e.g. low atomic number, smaller energy gap between 1st and 0th state, lower wavelength emitted when electron drops back down? If I'm correct this time that would mean, in answer to the OPs question, the difference in wavelength between tonic water and olive oil would be that olive oil has a smaller energy gap than tonic water, between the 0th and 1st energy state. I have a question though, what happens to the energy difference between the energy of the photon and the energy required to make the transition?
It would have been cool to put some of the fluorescent stuff in the UV part of the spectrum (from what I assume is an arc lamp) to show that yes, there's UV light there.
I'm having an incredibly difficult time placing Dr. Gray's accent / regional inflection. She sounds like she may have been born in Scotland but then moved to Canada or something. Certainly different glottal stops than would be used in Scotland or Ireland or the US or Canada, but certain words like "borrow" and "process" strongly indicate some Canadian influence. Anyway, she is a good speaker. Thank you for the video.
Sixty Symbols I would like to know whether UV light is considered ionizing or non-ionizing radiation. The sources I have checked seem somewhat contradictory. They usually state that most types of UV light is non-ionizing, but when checking what frequencies of light are considered non-ionising, UV C in particular & according to some sources UV B as well. Seem to fall in frequencies related to ionizing radiation. Like I said, contradictory. Thanks for your help.
I professor of molecular biology I had was teaching us about the effects of UV light on DNA. She was also telling about the complex DNA repair system we have. One enzyme need UV light to catalyze the repair. So she joked: "you go to the beach get a little bit of mutation, then you have to go again to not get cancer because of it"
I've always wondered: how come we can see ultraviolet light? I mean the lamp is UV, right? So why do we see it emiting the light at all (it looks just violet) if it's supposed to be outside of our visible spectrum? Shouldn't it be just totally dark to us?
Maybe show some Jablonski diagrams, they are pretty illustrative. Also, if you like fluorescence, search for videos on BODIPY, they're really nice and colourful :)
The first-year physics unit I took is compelling me to point out out a couple of things: 1. Ripples in the electromagnetic field? At least say that this is just a way of thinking about it. 2. Some of the electron energy is lost as heat? You've just said that infrared radiation is light, not heat. Also it results in electrons falling to lower energy states so it is not qualitatively different to the emission of the visible light.
I think when they said that some of the energy is lost as heat, they meant that the motion of the electrons increases the entropy of the system, not just that it emits the energy as infrared radiation (although that's probably happening as well). I could be wrong.
Heat is disorderly motion in molecules, atoms, and subatomic particles. She used the word heat to specify this phenomenon instead of IR radiation. When there is fluorescence, heat (as I have described here) is produced as well as visible light. This comes from conservation of energy, namely there is a loss of energy in the photons and that energy has to go somewhere; that somewhere is heat.
why does the sun radiate at all wavelengths? how do lightbulbs produce white light? Generally I thought that different materials radiated at specific frequencies when excited or combusted...
I have this question popping up my head after the video. What are the odd for light from millions light-years away to reach us, a teeny-tiny Earth. I think most EM radiation would be absorbed on its long journey.
Very Nice Video, could have even more science in it, other then making things glow. Brady, could you make a series of Videos covering every spectrum of light? Would highly appreciate it. Thanks
im from canada..and a thing i never understood is if you call "jello" "jelly" then what do you call jam that doesn't have chunks of fruit in it, because we call it jelly.. its all very confusing
in molecular biology, we use special chemical dyes that bind to DNA. upon binding, they fluoresce, and we can detect DNA like this and quantify the concentration, size and abundance of DNA! if you are interested in seeing cool pictures, google 'DNA electrophoresis'. standard practice for all molecular biologists exploring DNA molecules. thanks!
I have a question. If UV Light (from the sun) can cause cancer and sun damage, as well as a vital product in making vitamin D, can a UV Flashlight or UV Lamp, do the same thing? cause cancer and help make Vit.D? as in, is it dangerouse to have a UV Lamp on for a long time in a close range?
I have a couple lasers at 405nm. They're not strictly UV, but they're close and cause fluorescence like a black light does. Soon they'll probably make 385nm diodes available commercially and lasers made with those will be even more spectacular.
Pink doesn't exist - it's really just our brains combining blue and red light into one. If you take lots of really thin lines of blue, and lots of really thin lines of red, and stack them next to eachother, like on a piece of paper - you will see pink. Even though there's only red and blue there.
All colors we see are produced by the human visual system--including the combination of frequencies in the reflected polychromatic spectrum of light coming from ink on paper (even if that ink is red or blue ink).
I had some trouble detecting what accent that was as it was apparently a mixture of UK + USA but the vocal fry with some up speak definitely betrays an American.
I don't think the sun radiates all wavelengths right? I thought gamma was only emitted at the core and thus absorbed, and thus re-emitted at longer wavelengths
![Lp. Сердце Вселенной #60 РОЖДЕНИЕ ЛОЛОЛОШКИ [Финал] • Майнкрафт](http://i.ytimg.com/vi/YoR0pAV9FVQ/mqdefault.jpg)
Dr. Meghan Grey is extremely good at explaining physics. Keep up the good work!
*****
Lucky you! :D
She's class.
Dr. Grey will see you now :)
+Alex H You lucky son of a gun. Big envy! :)
Congratulations to Paul for finally making it into one of these videos! He's helped me a lot when I've been in the labs, great guy.
I have had one of my eyes' lenses replaced with an artificial one (cataract surgery) and I can definitely confirm being able to see slightly farther into UV in that eye. It's nice having only one of them removed because I can compare between the two eyes.
Nice effect of passing the camera across the spectrum at the end Brady! Love your vids and especially those featuring Dr. Gray.
An especially nice video. Thanks to everyone, but especially to Paul for his on-point light-switching skills.
3:00 We do get vitamin D from our food, most people just don't get enough of it.
***** Horrible misinformation is a bit harsh, although, to some extent yes, it is pretty awful. The fact is you won't get enough vit D from foodstuff alone, and so the sun is essential to get enough. It's not in A LOT of food though... It's more like a middle ground between your statement and the video's.
***** to be fair, they are astronomers not nutrition experts
I bought vitamin d because I live far north and we don't get a lot of sun during these months. I just hope they work lol
NorwegianQvirr I kind of agree that is horribly misinformed when it suppose to be a factual video. This is also such a old myth that most people should know better nowday
***** thanks!
So, the olive oil must emit more heat than the tonic water, because of the energy difference, right?
One of the best presentations I have ever had the pleasure of watching.
Much appreciated, thank you.
Recently, I purchased a U.V. flashlight and never really understood how it worked, and this video explains more about U.V. light. I really wish you'd show more household items and explain why they react U.V. light they do. Really enjoyed this video!
I am so glad she is back. I don't even know her name but I have such a wicked crush on her. It's ridiculous.
Eric Stone Thanks. .
HHahahaha :)
One of the best science clips I've seen in the past year.
Why is Dr. Gray so perfect?
Interesting to watch the ghosting at around 3:20 mark, looks like a nice display of the image stabilisation element(s) of the lens at work perhaps? (24-105 IS, Brady?)
Aside from this, another great video, Dr Meghan always explains ideas succinctly :)
I love listening to clever people talk about something they are really interested in. It's even better when I am too. Have a subscription.
Excellent video and a very good idea for a series of videos!!
I would have liked to see more on UV absorption though. As an astronomer, it might not be the first thing on your mind. But for the general public, UV absorption of sunglasses, windows, sunscreen etc. is incredibly important.
The highest frequency of visible light is roughly twice that of the lowest freq. of visible light, making the 7 colours of visible light (like the 7 notes of the diatonic scale) basically an octave. We hear the resonance of a high C and a middle C and a low C. Were we able to see beyond the visible spectrum, would we see the resonance of hyper red and red?
.
(BTW,... How you were able to resist lava lamps and wakachicka music I'll never know!..)
Glad to see Dr Gray back on Sixty Symbols. I assume she is still a regular face on Deep Sky...though I have to admit I have not wandered over to that channel in a long while. Something I will have to remedy (after I watch this one of course).
Think this is one of their best videos. Learning buckets.
Best explanation of fluorescence that I have heard. It's neat to know about the olive oil and tonic water.
What type of lamp and what size of prism did you use to project such a vivid bright spectrum?
What if there is no EM field present? (Say inside a conductor.) How then does light propogate?
The only perfect conductor is a superconductor, and inside those light pretty much doesn't propagate. Or rather, it can be described as gaining a mass.
Jesse Mason The EM Field is never "not there"; even at zero energy in the EM Field it is still present. In fact it cannot reach zero energy because of natural Quantum Uncertainty, we can't ever be sure a field has reached zero energy because there could be ± some energy in the field (uncertainty). The EM Field therefore does exist everywhere at all times: inside conductors, super-conductors, and even inside black holes!
We happen to now understand that the classical picture is wrong. You seem like a smart guy, why would you use a wrong model of reality? There is only one kind of light (not many forms with one being "normal light"), that comes in packets called Photons with varying wavelengths [color] and energies. Metals are typically opaque and shiny for other QM reasons (see photo-electric effect, etc.); not all metals are totally opaque, not all metals are shiny.
Rob Laquiere Because it can work as a well enough for the situation you care about. Do you care about the coriolis force when throwing a ball out for a dog?
I suppose I don't, but the fact remains that it is still there. I do typically leave out insignificant effects when doing calculations so you are right.
That blue picture in the video at 1:33 is a picture of "Cygnus Loop" for the ones interested.
thanks!
Being the RUSH fan, he is- Moriarty would catch that.
I didn't know that but I am interested. Thank you.
Cool, I rarely don't get lost at points in some of these videos but I really enjoy them.
So glad I watched this. I had never seen fluorescence demonstrated like that and I think the combination of the visual with the explanation that the energy it emits is lower because it loses some brought it together for me.
Thanks!
You could tell what their light source is in the first part of the video by the emission lines in the spectrum. Looks like fluorescent lighting to me.
I might be late to notice but I really appreciated the video quality and filming in this one! (Thanks Brady)
4:00 Should you not use eye protection when dealing with UV lights?
Around 5:19 you can see her top glowing because of the interaction of the UV light and the fabric whitener washed into her clothes.
How come at like 8:55 to the end, the lights in the background change colour as the angle changes? What is that!
it is the thing that was casting the rainbow at the beginning of the video
Is the fact that wavelenghts are larger towards slower frequencies the reason bass can't be heard well on small earbuds?
I really enjoy the way she explains things.
Dr Megan is so pleasant to hear speak. More vids with the good Dr please Brody
In what form is the mint that was added to the olive oil? Would like to do this kitchen experiment with my kids 😊
Meghan is just great, nice to see her again! :) Thanks for another good video!
woah, really well explained, I could listen all day!
GREAT idea for a Bradyseries! Looking forward to a trip across the EM spectrum.
8:52
That is a telescope image, so technically yes. But viewing it with just your own eyes, it would be far too dim to see those details.
As for rotation - absolutely not. Think about it. It's 220,000 light years in diameter, a single pixel in that image is as large as thousands of entire solar systems. The period to rotate one revolution is anywhere from tens of millions to hundreds of millions of years.
Mythricia Wow. Things are so huge out there. I can't even... how... wow.
We are just a bit of dust on all this!
Hugo Santos Indeed! And that's why Astronomy is such a humbling activity :)
It should be noted that we can actually measure the rotation of the Andromeda galaxy, even if we can't see it happening directly. So we do know it rotates, just like our own galaxy.
Hugo Santos no you cannot actually see the rotation when looking at a galaxy it is way too large to notice any change in position at the small timescale that humans use.
Love the new style of Sixty Symbols, keep it up, Brady :)
Interesting video. Makes me want to reassemble my TEA laser and fire it through some fresh olive oil and mint and try it on various fresh leafs. It'd be neat to see the red.
very interesting , thanks & keep making those vid's about light in all its glory !
Wouter Tomme so are you saying "Thanks for Enlightening us!"?
Onion juice also glows under blacklight. Works as a homemade invisible ink
Is there a limit to how short and how long a wavelength can be? I would assume shortest possible wavelength is close or equals planck length, while longest possibke wavelength is only limited by the size of the universe 😊
Well the energy limits the shortest wavelength, hence photons.
IamGrimalkin well.. yes, but is there a known limit? ☺
Ill Carl Electroweak unification might count as an upper limit, as you can't really distinguish "light" anymore.
Fluorescence is also an important analytical technique and so could have been discussed in a chemistry video as well!
I remembered Quinine emit longer wave length is light because the electrons jump up several energy levels when they absorb UV photons, then jump down one energy level at a time and emitting lower energy photons.
Will you guys be covering more of the electromagnetic spectrum? I'd really like to learn the basics about wifi-signals, microwaves, bluetooth etc. and how they relate to easy reception/amount of data that can be transferred etc.
Can you tell the purity of olive oil with the black light? Just asking because some companies mix other oils (canola) in with the olive oil claiming it to be 100% pure.
Since purple/white light is the only color light that will turn a radiometer. What happens to a radiometer under ultraviolet light?
I'm glad to see Dr. Meghan Gray doing good and well. It felt like I hadn't seen her on here in years..
what is the amount of energy stored in a photon of uv spectrum ?
When a photon of UV light is absorbed and an electron is excited to a higher energy level, surely the energy gap between the electron and the ground state is the same. The electron cannot lose that energy in different stages as energy levels are discrete, so why is the emitted photon not the same wavelength as the incoming one?
how can i ask bradys physicist buddies a question? i saw a vid of a guy burning sea water with radio waves. were just the impurities in the sea water burning?
Another example of fluorescence is the brightener in laundry detergent. Clearly visible on Dr. Grey’s vest.
The pre-roll ad won't leave the screen. Its done and now it won't go away - just frozen on the last image. So I can't watch the vid. I've gotten out and reopened the video twice and it plays the pre-roll commercial for 1800 contacts and then stops.
Nice to see Dr Meghan Gray again!
I can't help but wonder if the range of colors we see is by chance. It happened to be the most useful range for random attributes that previously made no difference to evolution, but once an efficient range was found for those random attributes, evolution was bound to them.
It makes me wonder if we do discover alien life, if they would even see in the same color range as us. Maybe they will be gray because their actual color is outside of our vision range.
This was interesting! Especially near the end of watching the cosmos through UV.
If the olive oil with chlorophyll emits red light, it means that when those electrons are excited, it loses MORE energy than that of the electrons in the tonic water. So my question is, what factors of the molecules determine how much energy the electrons lose after the photon is "absorbed". What makes the electrons in the olive oil lose more energy than tonic water, thus emitting a visible light at a lower frequency?
It's just the difference between the excited state, having absorbed a UV photon, and the next lowest state. In the case of olive oil it is not a large difference. So say the energy goes from 0 to 1 during absorption. It may only go from 1 to 0.8 during emission. If you want to know more it might be worth doing some research on the chlorophyll molecule, what atoms it's made up of and what energy level the various electron shells are at.
+SOEL86 it doesn't have to be the next lowest state, in fact, there is a rule in quantum mechanics, known as Kasha's Rule.
most (over 99.99%) of transition to the ground always take place from the lowest vibrational state of the first excited state, to one of the vibrational states of the ground state.
you can excite a molecules to any of its higher excited states, but it will usually undergo vibrational relaxation and/or internal conversion or intersystem crossover to another spin system, regardless, it will always undergo vibrational relaxations by colliding with other molecules and only emit a visible/NIR photon from the first excited state.
sidewaysfcs0718 Ah yes thank you. It was off the top of my head and I knew there was something wrong. So the difference in colour emitted depends on the nature of the molecule, e.g. low atomic number, smaller energy gap between 1st and 0th state, lower wavelength emitted when electron drops back down?
If I'm correct this time that would mean, in answer to the OPs question, the difference in wavelength between tonic water and olive oil would be that olive oil has a smaller energy gap than tonic water, between the 0th and 1st energy state.
I have a question though, what happens to the energy difference between the energy of the photon and the energy required to make the transition?
It would have been cool to put some of the fluorescent stuff in the UV part of the spectrum (from what I assume is an arc lamp) to show that yes, there's UV light there.
I'm having an incredibly difficult time placing Dr. Gray's accent / regional inflection. She sounds like she may have been born in Scotland but then moved to Canada or something. Certainly different glottal stops than would be used in Scotland or Ireland or the US or Canada, but certain words like "borrow" and "process" strongly indicate some Canadian influence. Anyway, she is a good speaker. Thank you for the video.
Sixty Symbols
I would like to know whether UV light is considered ionizing or non-ionizing radiation. The sources I have checked seem somewhat contradictory. They usually state that most types of UV light is non-ionizing, but when checking what frequencies of light are considered non-ionising, UV C in particular & according to some sources UV B as well. Seem to fall in frequencies related to ionizing radiation. Like I said, contradictory.
Thanks for your help.
"Hot young stars" made me chuckle.
Love Dr Meghan Gray's videos :)
Awesome video, can't wait to see what they will talk about when it comes to Gamma rays, also microwaves.
I professor of molecular biology I had was teaching us about the effects of UV light on DNA. She was also telling about the complex DNA repair system we have. One enzyme need UV light to catalyze the repair. So she joked: "you go to the beach get a little bit of mutation, then you have to go again to not get cancer because of it"
Question: can the UV from black lights damage your skin at all? I have done some research but apparently it's uncertain.
I've always wondered: how come we can see ultraviolet light? I mean the lamp is UV, right? So why do we see it emiting the light at all (it looks just violet) if it's supposed to be outside of our visible spectrum? Shouldn't it be just totally dark to us?
Maybe show some Jablonski diagrams, they are pretty illustrative.
Also, if you like fluorescence, search for videos on BODIPY, they're really nice and colourful :)
Very interesting and well explained. Thanks.
So I discovered one night while shining a black light around that bong water glows a rather intense shade of green. Anyone know the reason?
The avian and insect (and plant) world makes great use of the UV spectrum. Check it out some time. It's amazing!
6:21 Parents know where that little tightly-sealed container came from.
Only if they used them lol
The first-year physics unit I took is compelling me to point out out a couple of things:
1. Ripples in the electromagnetic field? At least say that this is just a way of thinking about it.
2. Some of the electron energy is lost as heat? You've just said that infrared radiation is light, not heat. Also it results in electrons falling to lower energy states so it is not qualitatively different to the emission of the visible light.
I think when they said that some of the energy is lost as heat, they meant that the motion of the electrons increases the entropy of the system, not just that it emits the energy as infrared radiation (although that's probably happening as well). I could be wrong.
Heat is disorderly motion in molecules, atoms, and subatomic particles. She used the word heat to specify this phenomenon instead of IR radiation. When there is fluorescence, heat (as I have described here) is produced as well as visible light. This comes from conservation of energy, namely there is a loss of energy in the photons and that energy has to go somewhere; that somewhere is heat.
why does the sun radiate at all wavelengths?
how do lightbulbs produce white light?
Generally I thought that different materials radiated at specific frequencies when excited or combusted...
It's all about the effective temperatures. Search Black body radiation.
The first i in quinine (i.e. the one following the u) is a short i in English.
A medical condition called aphakia?
4:43 So that's how they man Nuka Cola Quantum.
Blood Beryl Sorry. I should have put a trigger warning on my comment then.
Blood Beryl nuka cola isn't real
shune84 don't bring me back to reality **runs away crying**
Blood Beryl Evidently in your own unique universe that has been constructed from your own ideas and cognitive processes.
Hello lovely Dr. Grey! Where have you been?
I have this question popping up my head after the video. What are the odd for light from millions light-years away to reach us, a teeny-tiny Earth. I think most EM radiation would be absorbed on its long journey.
Very Nice Video, could have even more science in it, other then making things glow.
Brady, could you make a series of Videos covering every spectrum of light? Would highly appreciate it.
Thanks
Schweppes, please pay these folks some money. Scientists need more funding, and Gin!
Was this filmed by J.J Abrams?
im from canada..and a thing i never understood is if you call "jello" "jelly" then what do you call jam that doesn't have chunks of fruit in it, because we call it jelly.. its all very confusing
Proud to be an alumnus of Nottingham University :) 69-72
Wow!
Excellent I absolutely your videos.
Please keep posting
Laundry detergent also works great!
Love this channel
Great video!
in molecular biology, we use special chemical dyes that bind to DNA. upon binding, they fluoresce, and we can detect DNA like this and quantify the concentration, size and abundance of DNA! if you are interested in seeing cool pictures, google 'DNA electrophoresis'. standard practice for all molecular biologists exploring DNA molecules. thanks!
Looking forward to more videos about the electromagnetic spectrum!
I have a question. If UV Light (from the sun) can cause cancer and sun damage, as well as a vital product in making vitamin D, can a UV Flashlight or UV Lamp, do the same thing? cause cancer and help make Vit.D? as in, is it dangerouse to have a UV Lamp on for a long time in a close range?
Yes
I have a couple lasers at 405nm. They're not strictly UV, but they're close and cause fluorescence like a black light does. Soon they'll probably make 385nm diodes available commercially and lasers made with those will be even more spectacular.
where I can buy black-light bulb?
That was a very good explanation of the er spectrum!
\o/
Dr Gray is back!
And her dress glows!!
Have you noticed that there is no pink colour in the visible light (so there are no all colours in rainbow).
Pink doesn't exist - it's really just our brains combining blue and red light into one. If you take lots of really thin lines of blue, and lots of really thin lines of red, and stack them next to eachother, like on a piece of paper - you will see pink. Even though there's only red and blue there.
All colors we see are produced by the human visual system--including the combination of frequencies in the reflected polychromatic spectrum of light coming from ink on paper (even if that ink is red or blue ink).
Great analogy to just hearing a few instruments in an orchestra and just looking for visible light in astronomy.
I had some trouble detecting what accent that was as it was apparently a mixture of UK + USA but the vocal fry with some up speak definitely betrays an American.
Thanks Paul!
Thumbs up for Paul
I don't think the sun radiates all wavelengths right? I thought gamma was only emitted at the core and thus absorbed, and thus re-emitted at longer wavelengths