Sciencemadness Discussion Board

What to do with a long glass tube

mayko - 27-8-2018 at 15:15

I picked it up out of the university trash; I think it might have been part of a large aquarium heater. It's ~38", OD 1", thickness ~1/8", and closed off on one end like a long, wide test tube. It's not obvious what kind of glass it is, but if my guess about its origin is right I'd expect it to have reasonable heat stability.

So far it's an acquisition in search of a purpose. I haven't come up with an application that would really be suited to it's nature, other than maybe some sort of gas-phase reaction.

Any ideas?


[Edited on 28-8-2018 by mayko]

SWIM - 27-8-2018 at 19:30

If it's from a water purifier, it might be quartz!

Don't know an easy way to tell the difference, but if it is, it's one mighty refractory tube, and not a cheap item to buy.

Foeskes - 28-8-2018 at 04:42

Tube furnace?

MrHomeScientist - 28-8-2018 at 06:00

You can distinguish quartz from other glass by its ability to transmit UV light. Get a black light and something fluorescent, put the tube on top of the fluorescent object, and see if it glows when the light is shined through the glass. I did this in my video on burning diamonds.
It also sounds like a candidate for the barking dog reaction, but it might be a little narrow. You also run the risk of shattering the closed end with the pressure wave! I do that demonstration in a regular glass tube about that length and thickness, but with an OD more like 2". It's also open at both ends and sealed with rubber stoppers, so if too much pressure develops it will just pop those out rather than break the glass.

[Edited on 8-28-2018 by MrHomeScientist]

Heptylene - 28-8-2018 at 08:03

If it is not quartz, it could make a nice starting point for large ampoules of chlorine, bromine etc. for an element collection.

If its quartz you can cut it but you won't be able to fuse it or bend it without an oxygen/propane torch or similar. That's another way to test for quartz btw: if it looks like glass but you can't melt it, then its probably quartz.

Ubya - 28-8-2018 at 08:59

Quote: Originally posted by Heptylene  
If it is not quartz, it could make a nice starting point for large ampoules of chlorine, bromine etc. for an element collection.

If its quartz you can cut it but you won't be able to fuse it or bend it without an oxygen/propane torch or similar. That's another way to test for quartz btw: if it looks like glass but you can't melt it, then its probably quartz.


quartz when strongly heated is white, while borosilicate or soda lime glass will color the flame yellow

Deathunter88 - 28-8-2018 at 19:22

Easiest test for quartz that I know: heat a small part of it until it is really got (>300 degrees C), then plunge into cold water. If it's quartz, nothing will happen, if it's not, then it will shatter into a thousand pieces.

JJay - 28-8-2018 at 22:01

That will work for detecting quartz all right. I've personally performed that test, first heating the quartz until it was glowing red then plunging it into a bucket of water. The water will boil, but quartz will survive the treatment every time with 0 damage. Of course, lesser glass might not even survive the blowtorch.