Australia's Science Forum

We have a large aquarium at home, you should be able to wash the pads in plain hot water and reuse several times. After a couple of years you will probably need to replace them. Would recommend you do a wash at least a couple of times a year, but from memory, part of the overall filtration of an est...

I have experienced the same problem. I don't think it is a consequence of the NaOH forming Na2CO3 as the diluted solution would potentially have the same issue. I have put it down to the phenolphthalein in the universal indicator fading with time. "At a pH above 10 the pink color slowly fades a...

I would ask Chemwatch! Get them to explain why they have rated it DANGER! I guess they have determined the toxicological status of 6.5b 6.8A based on the ingredients, yet the supplier MSDS says it is approved non-toxic.

Hi Trish, GHS is the Globally Harmonised System for chemical classification and labelling put forward by the UN. We have been using it in NZ for a couple of years already. Not sure what your timeframe is! You might find this link useful... http://www.unece.org/fileadmin/DAM/trans/danger/publi/ghs/GH...

You might find this site helpful...
http://delloyd.50megs.com/moreinfo/buffers2.html
Cheers, Jane

Glass pH electrodes should not be stored in water as eventually the internal reference electrolyte solution leaches out of the electrode. The electrolyte solution (and storage solution) is normally ~3M KCl. Glass electrodes can sometimes be regenerated (if they are not too far gone!) by soaking in d...

We do the sticky tape thing here (also can still do cheek cells!) and it works well. Can't believe that would be banned, then nobody would be allowed to touch anybody!

Yep, did this yesterday, about 100mL of H2O2 in a 2L measuring cylinder with a good squirt of detergent (you don't need to worry about watering down the 35%), I use about 25mL of saturated KI solution, but straight KI works fine too.

Very cool, thanks Kiah!

FYI, the NZ EPA classify Manganese (IV) dioxide as 6.1B, 6.9A - no mention of the 5.1 status! Life is very confusing when not everybody agrees!

Don't pretend to be very good at Chemwatch, but when I looked up manganese IV oxide, it came up with two. 1. Merck Manganese (IV) oxide powder with Moderate hazard rating, and no mention of cancer warning 2. Manganese dioxide with Extreme hazard rating, and cancer warning. It would seem to me that ...

I am hoping to get new dangerous goods cabinets (both corrosive and flammable) in the near future. I noticed on one of the supplier's sites in the blurb about the corrosive cabinet this advice:- A small dish of calcium carbonate in the cabinet will help to neutralise the atmosphere Might be worth a ...

Would this be due to iron in the sand? (would form FeCl3 with HCl).

I had a lovely surprise the other day when one of the teachers left me a couple of bunches of tulips :D as a thank you for cleaning up the big mess of glassware she and her darlings made after attempting to make Oobleck! Actually all I did was pick it all up, give it a quick rinse and bung it in the...

We have just done this and it has worked well. The only things I can suggest are leaves need a few hours of sunlight first so don't do it first thing in the morning and rinse the leaf in water before putting it in the iodine solution.

Hi Nat,

Go back to your supplier. I heard of this happening with some product late last year. The problem is likely to be due to oxidation of the KI to iodine.

Good luck!

Jane

FYI, I got a couple of free periodic table posters from Ajax Chemicals here in NZ - not sure whether they are giving them away in Aus though! Just need to get them laminated...

Here is the one we use... Ginger Beer 2 Tbsp warm water ½ tsp sugar ¼ tsp dried yeast granules 1 c sugar Juice and rind of 1 lemon 1 ½ tsp dried ginger 1. Put first measure of sugar in warm water to dissolve. 2. Add yeast and stir. 3. Place in warm place to start the yeast working. 4. Put t...

I totally disagree with funding schools or basing teacher pay rates on the one off results of students. However is there not some way that the improvement of students may be measured over the year to test the efficacy of the teacher? Maybe some kind of initial knowledge exam retaken at the end of th...

Hi Ray,

Have you tried Micro Imaging? They are in Auckland, toll free number 0508 464 276.

Jane