Australia's Science Forum

My recipe refers to Lugol (Gram) Iodine and is 1g Iodine + 2g Potassium Iodide in 100mL water.

Yes, that's my understanding too. And opening a petri dish to take a sample of a growing organism to inoculate another petri dish.

OK, here it is again.

Zinc Sulfide (ZnS).
You also get Zinc Oxide (ZnO) and Sulfur Dioxide (SO2)
Carol

Zinc Sulfide (ZnS)

I bought mine from Serrata and no-one has had any problems.
Carol

Me, too, please.

carol.howes@det.nsw.edu.au

I think it was determined that Sudan II is the problem, not Sudan III.

Carol

I've just looked up fuchsin in CSIS and it is rated for Yr 11-12 - toxic if ingested, whereas SudanIII is rated for Yr 7-12 - moderately toxic. If you are looking at oil/fat in foods I would have thought SudanIII to be the safer option. I haven't found any reference to using fuchsin as an indicator ...

Do you have "waterglass"? It's a sodium silicate solution often used in making crystal gardens.
Carol

We use 0.05M sulfuric acid.
Carol

I think CH just means it's a chemical. Whenever I get chemicals from Serrata the invoice has CH before the chemical name.
Carol

Hi Mother
This was discussed earlier in the year under Sudan III.
In CSIS this chemical is rated as suitable for Yr 7-12 and not dangerous or hazardous.
Why do some people believe it is banned?

Carol

We're doing that same experiment this morning! I use a solution of sodium thiosulfate to decolourise the bromine water and then flush it down the sink.
If you look at Appendix E in CSIS you'll find Disposal of Waste Chemicals. Bromine water comes under "16 Oxidising Agents".

Carol

I have a list which claims 0.1M H 3 BO 3 has a pH of 5.2, 0.1M NaHCO 3 has a pH of 8.4 and 0.05M Na 2 B 4 O 7 has a pH of 9.2. I have another list of standard pH solutions produced by adding together various volumes of 0.1M citric acid and 0.2M disodium hydrogen phosphate. To make a pH5 solution, ad...

Well, I've just opened my pay docket - no increase or backpay this week. Rather disappointing!

Carol

We just use the usual lab transformers,which go up to 12V, hooked up to an induction coil.
Carol

Sharls, ours are really old but Serrata sells them: "1052047 CROOKE'S TUBES: Cross Vacuum Scale - Low pressure discharge tube set of 6 $185.00 Tubes mounted in line. The atmosphere inside varies in each tube. Electrodes at each end. DEMONSTRATES the discharging phenomena in rarefied gas. On woo...

Hi Sharls We have an instrument called a Cross Vacuum Scale, consisting of 6 Geissler tubes evacuated to different pressures (approx 40,10,6,3,0.14,0.03 mm Hg), in a box-like construction. Power is supplied to the tubes using an induction coil. I've copied this from the instructions in with the spar...

Thanks for the download, Noona. My flyer seems to have been lost in the mail. The office staff remember seeing a letter addressed to the Lab Assistant and claim to have put it in my HT's pigeon hole, which is where all my mail is delivered. My HT says she hasn't seen it and she's very reliable. So t...

Multi-tasking was tried here a couple of years ago. I didn't want to go anywhere else - I HATE answering phones - and no-one wanted to come into science. So I stayed put. Very happily.

Carol