I was filming a chemistry experiment recently to produce some teaching materials. This made me think about the liebig condenser, this is a classic item of chemical equipment. A great question is which way around to connect the water hoses.
If we were to attach the in hose at the top and the out at the bottom then with low flow rates it is likely that much of the surface which should be cooling the vapours will not be cooled with water. If we add the water at the bottom then more of the vapour cooling surface will be wetted with the water.
What I going to do is to set up a liebig condenser in the near future with the water connected in the wrong direction, I will then photograph the system and then restore the connections to the right way around and then take another photograph. I will have to wait until I get back to my lab before I can take these photographs.