Talk:Thistle tube

why do people use thistle tubes? Why not just pour in the liquid? 19:42, 11 October 2005 70.111.68.208

A thistle tube looks a lot like the description of the separating funnel, except without the tap. My guess is that it's used when a funnel is needed for a substance that needs to be coming in continuously, such as from a hose.
23:21, 12 April 2006 Fern

They are not used very often. In fact, i dont think i've ever heard mention of them being used. I don't recall seeing any in any labs i've worked in, either. Snazzra (talk) 03:49, 11 May 2009 (UTC)[reply]

They're mostly used for addition when it's necessary to add more liquid into the bottom of a reaction vessel. The long neck can reach the bottom, the reservoir bulb at the top keeps the air out. It also has enough volume that tiny pressure or volume changes inside the flask aren't going to suck or blow this seal fluid out, as it would with a cylindrical tube alone.

They're also used, not particulary to add more liquid, but as a pre-filled reservoir of liquid, to avoid having to continually check levels and top things up. Again, a small volume change inside the reaction flask is compensated for by the fairly large volume in the bulb.

Overall, they're probably more common in biochemistry than in chemistry.

I happen to have a vase full of them on my mantelpiece. There are little flower heads inside each thistle tube. They're more use as steampunk decoration than as lab glassware. Andy Dingley (talk) 11:36, 19 July 2013 (UTC)[reply]