Alternative pond weeds (Not emo I need something that works)

ChrisN

Jack of all trades master of several.
So according to the invasive plant directive I can no longer use Cabomba (rather and burning I use to compost it).

The teacher refuses to use Elodea as she says it never works (always does for me. 1% sodium hydrogen carbonate leave for five munities in a light and hay presto bubbles.) and is demanding something that always works. (Nothing always works unless you’re a chemist).

Does anyone have a secret pond weed species up there sleeves?

Chris
 
The secret I have is always to have a sample that has been "bubbling overnight" and miraculously filled a full test tube with oxygen. :cool:

All very impressive when they were presented with the just bubbling sample and the finished article. Teacher would then go and demonstrate that oxygen had been produced by introducing a glowing splint. Everything went fine until one day I was sitting next door to the classroom and realised I had mixed up my oxygen and hydrogen test tubes I had prepared for the day when I heard a loud pop. :D:rolleyes:
 

ChrisN

Jack of all trades master of several.
Everything went fine until one day I was sitting next door to the classroom and realised I had mixed up my oxygen and hydrogen test tubes I had prepared for the day when I heard a loud pop. :D:rolleyes:

Oops.

Unfortunally they are meant to be measuring the results. If it was just a demo I would fake it.

Chris
 
This came up in our Technicians' network meeting recently, apparently Hornwort (ceratophyllum demersum) is the way to go - works even better when grown alongside Elodea according to more than one technician. Main problem with Elodea is that bubbles are too small for pupils to see and is a bit slow in November when they want to do it - or January which is when I expect my lot to start asking.
 
I have found that both are successful until handed over to a classful of biology students and a teacher!
Whichever one you use a good trick is to cut the stem diagonally to produce larger countable bubbles and cut it whilst keeping it under water to prevent an airlock forming at the cut site. store them in a well aerated tank with strong lighting before the lesson.

Alternatively you could use algae suspended in algae gel beads and test the rate of photosynthesis with bicarbonate indicator. It is loads of fun but a mental leap for the students. When I offer this to the teachers who doubt the efficiency of pond weed they usually decide pond weed is fine after all!
 
Myriophylum works well. We have just used this for our year 10's and it worked just as well as the Cabomba - we did put a little sodium bicarbonate in with it too. I got it from Blades - it's currently listed under Cabomba but just ask for "Cabomba Substitute" :)
 
I use elodea which a colleague brings in from their pond. I store it in a tank under a light bank (daytime only) and place in a gratnell tray in warm water for the practical. There are always a few students who don't get many bubbles but using living things always means results are more unreliable. I have offered algal balls if we get really stuck but it hasn't been requested yet.
 
This came up in our Technicians' network meeting recently, apparently Hornwort (ceratophyllum demersum) is the way to go - works even better when grown alongside Elodea according to more than one technician. Main problem with Elodea is that bubbles are too small for pupils to see and is a bit slow in November when they want to do it - or January which is when I expect my lot to start asking.

Cabomba will grow well if kept out doors in a large plastic storage box full of water. The trick is to put 2" of soil in the bottom of the container and bury the basal end of the plant in the soil weighted down with a heavy stone. The plant should root within 14 days. It will die back in the autumn and regrow in the spring.
Ken Smith
 
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