The High Pressure Sodium Light: Ubiquitous, effective, but good?

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Ever wonder why street lights are orange? For such a fast-paced world technology-wise, it seems somewhat odd that we are still using such a strange color of light for outdoor lighting. Well it turns out it is still a pretty good light source, though with limited use and perhaps a not-so-obvious flaw.

Link to Part 2:

The video from The Engineer Guy:

Some various links:
The Wikipedia Article on Discharge Lamps:

An interesting source about lighting in general:

Spectral sensitivity of the eye (this is a bit of a spoiler for the next video, so open with care):

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[woody]

When I was a little kid, maybe 6, my dad worked as a welder. One day he brought me to work. He would to start his drive at 4am. I remember riding through the city on the bench seat of his 80's Mazda B2000 pickup. This is the first time I remember seeing the glow of sodium lights covering everything I could see in a soft, warm orange light. We lived in the country and I had seen singular streetlamps, but never anything like that. Passing under rows of lights on the urban interstate and through the city. That was over 20 years ago and every time I drive on a road at night lit solely by sodium lights it takes me right back there to simple times with my dad, a humble welder, but still my hero. Technology changes, but I hope there is never a night when there is no sodium light remaining. Maybe I'll tell my grandchildren about the warm, calming glow of the past. But words can never convey the magic i felt.

[bjornroesbeke]

I remember having white street lighting some 20 years ago. Then they changed it to orange.
The orange glow makes it "feel" more like nighttime.

[cameronwilson]

As a sparkie (electrician) we were also taught that the orange light is particularly good in areas with fog, similar to the yellow fog lights on cars.

[khandapwner]

1:01- 1:09 is the best explanation on how a lightbulb works that i have ever heard of.

[TechnologyConnections]

For a channel with an icon of a light bulb, I sure don't do a lot of videos on lighting tech! Time to change that.
Added note: the HPS lamp is not the first mainstream discharge lamp. Mercury vapor technology preceded sodium by decades, so we've already done a massive change once before. We'll look a bit at mercury vapor in my next video, and we'll go a bit more into the history of these lighting solutions. But for now, I hope you enjoy this introductory video!
EDIT: In the video, I said I wasn't very good at chemistry. Some people have pointed out that this sort of thing is more studied in physics. Aside from proving that I wasn't very good at chemistry, I am genuinely questioning whether or not I first learned about this in Chemistry or Physics. I am _pretty sure_ we discussed electron orbitals and photons produced when electrons jump to lower energy states (plus I know we learned about ionization in chemistry), but I am _certain_ that we looked at gas discharge phenomena in physics class. So both maybe?

[avenged]

I loved these lights. In my city, they would cast a warm glow that covered pretty much everything in a pleasant, relaxed light. Now that they all got replaced with LEDs, there's a tiny cone of very dim white light under the poles and total darkness in between, making them relatively worthless at actually lighting the streets.

[RainWalking]

Love this guys videos. He makes everything feel so Retro but in HD.

[Rikorage]

That random "Yeah" at 12:22 threw me pretty hard, had a good laugh there.

[ybunnygurl]

Well a few years in and by me the city is switching over to LEDS, but after testing my city is using warm light LEDs, not bright white, or daylight. They cast light like a incandescent bulb. Its wonderful, and really cuts down on light pollution and are easy to see.

[zekefleming]

We have a sodium light above our barn, dusk to dawn every night it’s on. The same bulb has been in place sense 1983. Pretty impressive!

[videolabguy]

I parked my fire engine red bicycle against the lamp post in front of my friend's house when I was about 8 years old (1963 or 4). I stayed until after dark. When I came out, someone had stolen my bike and replaced it with an identical bright purple glowing one! I squalled all the way home! Dad came back with me to see what the fuss was all about. Yep. I caught a case of the Sodium Vapours! If he were still alive, Dad would still be chuckling at me!

[Creeperboy]

There’s something nostalgic about sodium lighting
Perhaps the memories of road trips to Illinois through the night, or how the property at my summer camp was lit up with these at night, providing a 60hz hum with the cricket ambience

[thomashernandez]

I love sodium lighting. So easy on the eyes and lights up everything.

[abborne]

I don't know if it's just me or if you're getting to the science behind it, but every LED street light I've ever encountered was real good at illuminating a one-square-foot patch of road directly beneath it.
But with all that extra color accuracy, I can definitely sort of tell the road surface is approximately black and the curb is approximately white.

[TimurTripp]

In my neighborhood they recently replaced all the sodium bulbs with modern white LEDs. Was kind of disappointed to lose that nostalgic orange glow.

[KylesDigitalLab]

This is a really good channel, love your work

[rarsn]

Okay, I thought one of the reasons sodium bulbs were used for street lights was that the yellowish color was better for enhancing the contrast of items being lit up. I mean, in Europe fog lights were usually tinted yellow for this reason. Likewise, the silly trend of putting blue headlights on your car is stupid because blue light makes less contrast, therefore objects are harder to distinguish than yellow, or something.

So I found this video quite interesting. I was in the Navy and one of my jobs was to monitor personnel dosimetry (radiation levels). We had devices that each person would wear on their belt called a TLD (thermoluminescent dosimeter). There was an element in the cap to absorb neutrons, but what we mainly focused on was the glass capsule stored inside the case. It was basically a wire with some calcium flouride crystals attached to it, and when photons hit the crystal, it would send electrons into an excited state. So every quarter, we'd read the dosimeters by inserting them into this machine, which kept them in darkness and would apply a voltage to the dosimeter which would result in the electrons returning to their normal state... which produced light. So the machine would calculate the dosage received based on how much light was emitted.

I was reminded about that when you started talking about electrons. I didn't realize how similar they were. Great stuff!

[gentillydanny]

When I was a kid the Interstate system was still being built. I was twelve (1969) when the section near our house was first lit at night and I was amazed how the hundreds of birds that had nested there were so restless and noisy. This went on for awhile until they'd all moved on or died from exhaustion. Circadian cycle into chaos.

[EVRLYNMedia]

Today i learned that my teacher in 2nd grade wasnt talking bs when she told everyone to never shut off the metal hallide lights in our gym

[Doggieman]

Keep in mind, too, that these orangey lights are more akin to the light coming from the really old gas lights that dominated the scene for decades before. The whiter LEDs are harsher on the eyes at night.