Cleaning test tubes

[smiley]

We don't do a galvanized alternative. However we do this as a two-stage experiment. Stage one is water, slat water & air. Stage 2 is where the cherubs have to design their own experiment, with a limited range of gear - e.g. oil, boiled water (to remove air), varying strengths of salt water etc. We do offer to place other metals in the cups as a form of sacrificial anode (although we don't use that terminology with tinies). We are following the National Curriculum and frankly, I just do what I'm told. However, one could always just chuck in a tiny galvanized nail, and compare I guess.

[RosalieM]

Ah yes - boiled water with oil on top to stop gas exchange! That's the one I was thinking of. And I think they do salt water as well. Definitely will be promoting this idea to the teachers!!!

[kimmy]

I have a bucket of HCl for cleaning of glasswear. I wait till i have a bit that needs doing and I soak it over night. Works every time.

Good luck.

KIMMY

[mtg]

Re rust pracs -Bi-carb soln prevents rust. I've had a prac going since 2005 and while some of the testtubes with water, salt etc and nails are completely rusted to soup the bicarb just keeps on giving. I just top it up every so often. Gets 'em thinking.

[cherrycat22]

I just keep all the rust effected test tubes set aside for next year

[bigmack]

Teacher accidently grabbed the sodium carbonate instead of Copper carbonate .
Now have half a dozen side arm test tubes with glass like crap in them which won't budge .
Any suggestions ?

[Milo]

I suggest changing the locks on the chemical storeroom :p

[Wayne]

I did that here Milo! I am the only person with the key!

[Merilyn1]

Scienceassist recommend only the lab assistant, head teacher and possibly the chemistry teacher have access to the chemical store. This is a WHS issue. Limiting access makes perfect sense. As far as the test tubes go, I'd just throw them away. Your time you've already spent on them is worth more than they are.