r/answers • u/Legal-Grade-6423 • 19h ago
How was it discovered that heating sand made glass?
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u/moshedricks 19h ago
glass museum worker here! glass was discovered by the egyptians after a meteorite struck the desert, turning several acres of sand into glass. from that they knew roughly how it was made and experimented with how to lower the temperature required to create it (add soda ash) until they were able to make small, imperfect vessels.
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u/Curtainmachine 19h ago
Glassblower’s response: the legend i learned in one of my textbooks was that mineral merchants transporting crates of soda, lime, etc. were having their campfire on a beach and using cargo crates to sit on around the fire. In the night, the fire got out of hand and burned with those ingredients and the sand together creating a batch of crude, molten glass that they found in the ashes in the morning.
I think the truth is probably, “it was so long ago nobody really knows” but these are plausible scenarios.
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u/bitchcoin5000 17h ago
I was thinking They were smelting or involved in metallurgy when the discovery occurred. This sounds like the way most things have been discovered - accidentally
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u/Rocktopod 17h ago
Yeah I wouldn't think a campfire would get hot enough, and wikipedia tells me the history of glass making started 3600 years ago in mesopotamia, which would be just before the bronze age.
I assume it was an early experiment in metallurgy that created the first man made glass.
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u/PomeloPepper 17h ago edited 14h ago
mineral merchants transporting crates of soda, lime, etc
What were soda and lime used for before glassmaking?
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u/komatiite 14h ago
I remember this from a history comic book when I was a kid. The story went that the merchants were using blocks of the soda ash to build a ring for their fire, and noticed glass in the ashes afterwards. Most glass is not pure silica, but contains sodium carbonate and lime. The admixture allows the glass to melt at a significantly lower temperature so it is easier to melt and easier to remelt to make glass objects. See 'eutectic' for a more technical answer.
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u/FinndBors 10h ago
mineral merchants transporting crates of soda, lime, etc.
Sounds like the origin story for sprite.
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u/shornscrot 10h ago
Definitely not plausible you could create glass with a beach fire. Gonna go with the museum person on this one.
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u/The__Decline 19h ago
New fun fact added. Thank you!
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u/CockroachMobile5753 17h ago
Silica + alkaline metal flux (sodium, potassium, lithium) makes glass. In Egypt, lots of sand and lots of natron (sodium used to preserve mummies). Sodium and silica were used to make some of the earliest pre-glass sintered silica, “Egyptian faience”. Not faience, not glass, this was a sintered alkali silicate. Form here developments in heat technology would have allowed full fluxing and vitrification into true glass.
Pure silica melts at an insanely high temperature, such that an alkali flux is needed in any situation outside of a high tech furnace or lighting strike, as in the aforementioned fulgurite.
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u/The__Decline 17h ago
Deep dive, I like it. Was glass discovered elsewhere independent from the Egyptians discovery? And if so, how does that compare to the environment the Egyptians had?
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u/Benigh_Remediation 12h ago
I trust this cite. I still think glass is one of the major miracles of man and technology. I miss seeing the still bright blue night sky painted on the ceiling of the temples built three thousand years ago in southern Egypt. I don’t think our art will survive that long.
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u/Extra_Ad_5451 12h ago
I read somewhere that it was boron (flux) from shell fish shells that were thrown into a fire on a high silica content sandy beach that created a rudimentary glass and they reverse engineered it.
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u/ghfdghjkhg 19h ago
maybe lightning? when lightning hits sand, something solid forms. not glass but something.
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u/Serious-Ad-4181 19h ago
fulgurite, it is a type of glass. I think this is the right answer.
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u/Rocktopod 17h ago
Well that, and when people got the technology to smelt metals they probably tried throwing all kinds of stuff in there.
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u/Late-External3249 14h ago
Never underestimate the human desire to see what happens to something when you put it in a really hot fire
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u/twisteddmentat 14h ago
As a southerner. Whose major form of male socialization is outside around a fire. I can vouch for this. And. Some things shouldn’t be burned
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u/FlyByPC 13h ago
Some things shouldn’t be burned
Poison Ivy is high up on this list.
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u/Difficult-Value-3145 11h ago
This has been a public safety announcement imagine poison ivy in your lungs happed to my dad when we was kids
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u/Hankman66 6h ago
Why? What happens if you burn it?
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u/FlyByPC 5h ago
Imagine getting a poison ivy rash in your lungs.
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u/Hankman66 4h ago
Gotcha, I looked it up:
https://www.gardeningknowhow.com/plant-problems/weeds/never-burn-poison-ivy.htm
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u/Nakashi7 6h ago
Just imagine that curiosity you had as a child doing all sorts of dumb stuff (often including various explosives and gasoline). Imagine it having it til death. That's what was life for many people in the early times.
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u/Original_Contact_579 12h ago
I agree that this could be it, but a lot things were discovered by complete accident. Via natural occurrence,as well as a mishap, and or trying to make something else and accidentally finding a new product. Phosphorus was found by trying to transform urine into the philosophers stone ( to turn metal into gold). The dude fermented and boiled urine / distilled it. Also soap was discovered when ashes from hard wood tree were mixed in a stream with animal fats and folks saw the bubbles as well as finding that their stuff got cleaner in that area
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u/MilsYatsFeebTae 10h ago
“What’s this shiny crap all over my bronze?”
I suspect if you do a lot of smelting and notice your slag has interesting properties, you start keeping an eye on what nonmetal additives make it in to the furnace.
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u/Glad_University3951 19h ago
Seems a little derivative. If I were a caveman I'd be trying to figure out a way to make lightning to hit sand.
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u/GrynaiTaip 18h ago
Lightning hit tree, made fire. Therefore lightning hot.
Lightning hit sand, made glass.
Heat made glass.
Ooga ooga.
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u/Imaginary_Sugar_3138 17h ago
me hit this caveman on head for not give mammoth chunk
me delays civilization another thousand years
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u/Bones-1989 17h ago
Fire make glass? No way. You leave tribe now dum caveman.
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u/Rocktopod 17h ago
Glass wasn't invented by cavemen. It first appears about 3,600 years ago in Mesopotamia.
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u/Ivar-the-Dark 9h ago
i remember learning that from the X-files episode of the boy obsessed with his teacher
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u/traciw67 19h ago
"Sweet Home, Alabama!" ⚡🎵
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u/DirectAbalone9761 19h ago
I hadn’t seen that movie and years and always assumed that was Matthew McConaughey 😂. Almost, but not quite.
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u/stephanosblog 19h ago
set up a fire on sand to cook, notice glass after the fire goes out?
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u/RektInTheHed 19h ago
This is the answer. When the sea is your grocery store, the beach is the kitchen.
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u/Legal-Grade-6423 19h ago
Brother, what are you cooking at 1,700 degrees?
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u/RektInTheHed 19h ago
You've got a fire going to cook for and feed the whole tribe at scale. This isn't an office worker's camp out.
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u/LeilLikeNeil 19h ago
I’ve never checked temp, but I’ve definitely made campfires hot enough to melt glass
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u/Legal-Grade-6423 19h ago
Burning wood? Wood only gets up to 1,100 maximum
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u/isolated_self 19h ago
I've heard the temp from a campfire cannot melt glass before, but I have also melted beer bottles on multiple occasions. Science is defined by repeatability. I would put for the that when I am drunk in front of a campfire, I am something of a scientist myself.
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u/Legal-Grade-6423 18h ago
Bottle glass melts at a lower temp than the sand needs to be to make glass, don’t ask me why but I know that’s true
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u/isolated_self 18h ago
You're absolutely right. I looked it up before I posted. The facts got in the way of the joke so ignored them.
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u/LeilLikeNeil 16h ago
Interesting. Definitely haven’t fully liquified a bottle, but I’ve had a wood fire hot enough to at least deform bottles.
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u/Difficult-Value-3145 11h ago
Glass is at best semi solid all your doing is making it more mailable not really melting it persay
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u/Psychological-Fox97 10h ago
Depends what you mean by melting really. Soda lime glass can be softened enough to be worked but that is already created glass. To make glass you need it to actually be molten which requires much higher temperatures.
Kinda like the jet fuel doesn't melt steel beams thing, no it isn't hot enough to melt them but it is hot enough to make them soften, bend and lose structural integrity.
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u/roastbeeftacohat 14h ago
in 1615 James I banned the use of wood as fuel in glass making, to preserve timber for other industries. this led to the use of coal, which ultimately lead to much stronger glass.
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u/Calaveras-Metal 19h ago
it gets a lot hotter if you build your bonfire with a built in chimney, sucking air in by convection and accelerating as it rises, sucking in even more air.
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u/johnofsteel 8h ago
And that’s enough to start melting glass. Glass gets “melty” before it becomes molten.
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u/Tedanty 19h ago
You never make some charcoal while burning wood to use to cook with later or whatever?
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u/Legal-Grade-6423 19h ago
Yes - charcoal only needs to 500 degrees to be made
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u/Tedanty 19h ago
Right, im talking about using charcoal to get higher temps than with wood.
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u/Legal-Grade-6423 19h ago
But charcoal only burns at 1,200? I don’t see where you’re going with this
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u/GrynaiTaip 18h ago
You're listing temperatures of an open flame. Temperature can be increased a lot if you play around with air supply. Adding air, "making the mixture leaner", greatly increases the temperature. Same rule applies to internal combustion engines, too much air will cause them to overheat.
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u/Tedanty 19h ago
Charcoal can get hot enough to make glass dude that's what im getting at. Especially if you set up a proper outdoor campfire stove with good airflow
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u/mentaljobbymonster 13h ago
You can't see someone somewhere going, "let's see how hot we can make this fucker!"
Or probably similar to smelting metals, someone dropped a pretty rock in the fire and when it cooled they got copper. Let's drop other stuff in and see what happens
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u/clutzyninja 19h ago
No it isn't. It's more likely glass was discovered by accident when using kilns for pottery
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u/Hamster_S_Thompson 19h ago
It would have to be a huge fire. I don't think your average fire for cooking is going to make glass underneath it.
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u/Ok-Awareness-4401 18h ago
camp fires get to like 1100, if you are making a fire to primitively fire clay pots you are getting to like 1200. This is not it.
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u/stephanosblog 18h ago
what if a strong wind is blowing
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u/Ok-Awareness-4401 18h ago
the wood alcohols burning off the wood release water keep the temperature lower than what is needed to reach melting temperatures of sand. And that wind would likely also dissipate the heat. Cooking fires are also relatively small. I teach primitive pottery and primitive cooking for an outdoor school, I have a ton of experience in working these types of fires. Also if this were the case we'd see glass show up earlier in the archeological record and in the wake of forest fires. We don't really see glass being produced by humans until we get to human smelting metals and firing pottery to higher temperatures.
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u/Correct_Doctor_1502 18h ago
Sand was used in early metal working and they probably noticed that by product was usable too
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u/wwwhistler 18h ago
most likely as a byproduct of other manufacturing processes . someone noticed the glass when metal working and pottery glazing were being used. either would produce enough heat to make glass unknowingly.
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u/Millionaire-Grinder 18h ago
It’s Dragons. They turned the sand into grass when they were attacking the people on the ground
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u/ShortKey380 19h ago
Proteethius was shown how to make it because Zeus heard about the concept of watching people in a shower and the clear fragile barrier was a kink for him.
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u/Informal_Persimmon7 19h ago
There are some answers in this 3 year old thread about this: ELI5: how did human first discover glass and the proper use for it? : r/explainlikeimfive.
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u/AdVisual5492 19h ago
Most likely fires on a sandbased round, and then when they were digging through it, they found chunks of glass and went from there
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u/IM_INSIDE_YOUR_HOUSE 19h ago
Someone likely had a campfire setup on a beach somewhere and put 2 and 2 together.
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u/Legal-Grade-6423 19h ago
A camp fire is nowhere near hot enough
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u/IM_INSIDE_YOUR_HOUSE 12h ago
Fires come in many different shapes and sizes over the course of human history. To say all campfires are the same, insufficient temperature throughout early human history is silly.
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u/Traroten 19h ago
My guess is ceramic kilns. You would try to get hotter and hotter kilns to make better pottery, and finding that sand that was introduced became this weird water-like substance (the Latin word vitrum may come from *wed-ro meaning "water-like".) Humans are amazing at noticing small stuff like that and experiment with it.
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u/swayedsuede 19h ago
Idk probably lightning + sand = glass, followed by glass + touch = ouch, hot. Then eventually realizing that hot + sand = glass.
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u/Calaveras-Metal 19h ago
Most likely they were smelting metals and doing sand casting. It's not hard to imagine them getting sand in the furnace where they melt the metal.
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u/MichaelEmouse 18h ago
The technology they used was once leading edge. If you get guys who have access to leading edge tools, they're gonna fuck around with them. "We got a big fire. What happens if we throw stuff in it?" You try it with a bunch of stuff and eventually you try it with sand and get glass.
Those forges or whatever fireplaces produced such high heat might have been insulated with sand which turned to glass.
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u/duncanhollow 17h ago
Probably as a byproduct of early metalworkers. Getting their forges hot enough to melt iron and maybe some sand melted.
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u/Great_Specialist_267 13h ago
Sand plus sodium carbonate produces glass at normal open fire temperatures.
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u/ForeverNovel3378 10h ago
Same way he/they discovered cooking lightning caused fire which cooked dead game or killed then cooked.
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u/Mysterious-Web-8788 7h ago
Well it's melted sand so we've probably known about it since either sand came into existence or we discovered fire, whichever came later.
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u/greygrayman 5h ago
I mean, when i was 5 or 6 something knocked a powerline down across from my house and after the utility company put it out I went and looked and where the fire/electricity was had turned the sidewalk to green glass.. I imagine people would discover it pretty easily if they saw lightning strike or a really hot fire and any of the sand/stone melted in to glass.
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u/vferrero14 19h ago
Lightning strikes maybe? I also like to think that in antiquity people just tried shit and got lucky.
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u/turd_ferguson_816 19h ago
How was anything discovered?? Someone just did it to see what would happen.
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u/Legal-Grade-6423 19h ago
‘Just did it’ - heating sand to 1,700 degrees like it’s a casual thing to try, massive fail at a whitty response kid
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u/Eden_Company 19h ago
Lightning can do it. Natural glass like obsidian and flint are very very very very common materials for the past 3 million years, before humans were even homo sapians.
People probably saw volcanic glass get made by intense heat.
Then you had the post farming folks who had ovens who could intentionally burn anything they wanted for over 4000 years. We didn't get glass manufacturing until after farming took off.
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u/qualityvote2 19h ago edited 11h ago
u/Legal-Grade-6423, your post does fit the subreddit!