Australia's Science Forum

Yes.

Can anyone tell me if Potassium iodide is the alternative to Manganese dioxide for oxygen gas. I know its on here somewhere Yes, potassium iodide should catalyse the decomposition of hydrogen peroxide into oxygen and water. And indeed it works as well as expected. I just slipped some 6% peroxide in...

I use dropper bottle trays which have removable partitians to get approximately 3 cm sided blocks that the students can easily cut down to size. Also, I store the agar blocks in sealed tupaware containers to prevent drying out before the prac. They can be stored that way for considerable time. I hav...

We have a sets of 5 rods to show expension of metals. They are Griffin & George brand but look ancient. We can work out copper, steel, iron and brass but there is one that looks like copper we are unsure what it is. Anyone have any of these and know what they are? Of course there is no key and ...

Lyn wrote:Am I wrong to recycle the hay infusion back into the garden?

Uhm... Well, it should be safe enough, but reguardlessly, I do believe we are required to sterilise any and all microbiology growths before disposal.

Technically. Just in case.

Better safe than sued.

How nasty are the protozoans, parameciums and other bugs that grow in "Hay infusion"? I can't find a lot of info on safe handling/ disposal. Gloves and disinfectant/alcohol?? The protozoans and bacteria grown from ordinary pond water using hay infussion are mostly harmless. Safest handlin...

fishy wrote:Hi, can anyone tell me where the name 'pluck' came from? Can only find one thing that these body parts were plucked from body ...

That is actually it.

The pluck is the name given to the group of organs that are plucked from the thorax by the trachea. It's not any more involved that that.

We have a Wimshurst generator. Is it a similar thing?? No, not quite. Different principle. No magnets involved. It has two insulating discs, with metal strips inset into their surfaces, rotating in opposite directions (turned by a mechanical handle) passing crossed metal bars, with brushes, which a...

Does anyone know, what it is and who would stock it? We have a very old one, which has 2 metal discs joined by a leather band( a bit like dynamo), with magnet attached to one of the discs. Teacher wants a newer model Thanks, Lada Yeap, it is a dynamo. The forerunner of dynamos rather. Invented by M...

If you need blocks you would use more agar, I am not sure of shelf life though, Blocks of agar agar for "'cell' volume and surface area" practicals can be made using 20-25g agar agar and 100g salt as a stiffening agent. The blocks are then stable enough to be handled by students; and the ...

Thanks Lisa for replying. I thought it might be the amount of agar I used or the agar being old. Agar agar has a fairly infinite shelf-life; just so long as it's kept dry. To make a litre, disolve 15-20g agar agar, and nutrients, in about 850mL of cold distilled water. (Eg: 5g peptone, 3g beef extr...

Jazz wrote:how did youn get such precisse molarity. have you done titration? It is not easy to make up NaOH with such precision. or it just me

It's not just you. NaOH just can't be accurately weighed; it adsorbs moisture too readily. Any precision has to come from calibration after preparation.

HI i have about 1.7L of 0.632M Naoh. I want to make it up to a 1M concentration. How do I work that out? Sorry brains gone to mush.Was trying C=nv and n=m/mr got myself all fuddled Thanks Krysia I'd add 37.0 g and dillute to 2.00 L final volume. ((2.00 L) (1.00 M) - (1.70 L) (0.632 M)) * (39.997 g/...

To summarise: Copper(II) Sulfate is supplied in two forms: Anhydrous and Pentahydrate. The difference is the degree of hydration; the amount of water of crystalisation contained within the crystals. Both form copper sulfate solution, since once disolved they are no longer crystals. If you let the so...

I always add 1ml of conc H2SO4 to my Copper sulfate when I make it up. It stops the yellow precipitate coming out and keeps it a nice blue colour. Not sure what the precipitate is but the acid helps. The precipitate is copper. Fine particles of copper metal that are reduced out of solution. Acidifi...

And meanwhile, closer to home: http://www.abc.net.au/news/2013-05-10/e ... en/4682220

A line has got to be drawn somewhere, because crossing it can be tragic.

It's the "unsupervised" and "playground" parts that are the problem.

Discoraging students from playing with explosives on the playground is a good idea. Even mild ones.

Still, using federal criminal prosecution to do so might just be a something of an over reaction.

My tip is simply never to pour silver nitrate solution; to minimise Murphy's Law of Fluid Transfer. (Anything that can flow wrong, will flow wrong.)

Always use a pipette to transfer from stock to sample bottle, or into test tubes, thus keeping the rims dry, and avoiding dribbles.

Please explain.

Is this something ado about peanut allergies?

That would be my guess, anyway.

I'm new to using riskassess and into my second year of being a labbie. I'm just wondering about assessing the level of risk as low, medium, high or extreme for each experiment. It seems that it's a little bit subjective. Does anyone use the standards or risk management guidelines (suggested by the ...