Australia's Science Forum

Loopy wrote:Oh Rosalie!
Where is the "little green with envy smilie" when you need it!

At the end of the list there's:

But we really need something like this:

My first thought was butric acid. But a bit of trivia I learnt this morning. You all know Formic acid smells like dead ants, well Italian for ant is formica Indeed. More precisely, Formic Acid is sprayed by many species of ants when they bite, to inflame the wound. It is why ant bites sting so much...

Just wondering how much notice you ask your teachers to give you for EEIs? Do you stick to the usual 48hours as for pracs, or do you have a different set timeframe for EEIs? I prefer longer because: (1) EEI often have rather unique requirements that take time to find, order, or negotiate substitute...

Well, it does depend on just how blunt they become, but yes, cutting scaps of steel wool will extend the sharp life.

It's called Lugol's Iodine Solution. (I2/KI). For school practicals use: 15g KI, 3g I 2 , disolved to 1000L volume in H 2 O. First disolve the potassium iodide in just a small amount of water (~20mL), then add the iodine to this. Only once the iodine is disolved, do you make up to final volume. A sm...

The iron and sulfur experiment is a classic for a reason. I can't think of anything else that would do the job. Both elements are solids at room temperature, as is the product. They do react well when heated, as long as you mixed them throughly beforehand. The change is clearly visible. In addition,...

There are probably some implications with boiling it with the NaOH and phenolphthalein already in it though! :whistling2: Well, Phenolphthalein is a laxative and suspected carcinogen, and you don't really want NaOH in food either, so make sure that the containers remain sealed! Or use a dedecated s...

If anyone could help I would appreciate it- my agar plates looks cloudy. I can see tiny particles suspended I am using 2g vegemite 1g bonox 5g NaCl 5g peptone 15g agar as per previous lab tech recipe mix on magnetic stirrer on heat then pressure cook for 15min in conical flask Q- am I meant to let ...

Finally back on line, will be trying the crystal tree tomorrow, sounds like most sat solns for crystals should work? What's the silver crystals on copper? Is it silver nitrate and how do you get it on the copper? Suspend a thin copper wire (or tuning) in silver nitrate solution, then just let the c...

I set this up on Friday using Pascoes Bluo that i got and Coles and am very dissapointed in the results. :redcard: Nothing much has happened. The liquid didn't migrate up the cardbord tree at all and there are no signs of crystals. I did use ammonia but I did use my neat ammonia which may have been...

If it were absolutely necessary to have ferrous nitrate, you could react ferrous sulfate with (lead or barium) nitrate and decant the solution off of the precipitated sulfate. FeSO 4 (aq) + Pb(NO 3 ) 2 (aq) => Fe(NO3) 2 (aq) + PbSO 4 (s) FeSO 4 (aq) + Ba(NO 3 ) 2 (aq) => Fe(NO3) 2 (aq) + BaSO 4 (s) ...

Bluo. It's hard to tell, but I don't think so. Pascoes ' MSDS isn't particularly forthcoming about the contents. However, Bluo appears to reference a use of optical brighteners rather than bluing . Bluing is just a bit olde tech. ---- Check your chemical inventory for a less kitchen-sink approach. ...

Prussian Blue is the main reagent in Laundry Bluing Liquids, which are used to whiten cloth.

That should work out fine; producing fluffy white crystals from memory.

To add some colour, just add colouring. Soak the tips of the carboard cut out branches with food colouring. The crystals will pick up the dye as they grow through it.

Yeap. That's basically all it is to it. Starch forms a tightly coiled spring in solution (almost torus-, or donut-, shaped). The linear triiodide ion ( I 3 - ) slips neatly into this coil to form an ionic complex; in which position its vibrations are constrained. Thus causing its change in absorbanc...

Yes. Anhydrous FeCl 2 is 126.7516 ± 0.0003 g/mole. To prepare 500mL of 0.100 M, take 6.34g, disolve in ~450mL, add ~2mL conc. H 2 SO 4 , then dilute to the final volume of 500mL. (Don't add the acid after you make to volume!) Tetrahydrous FeCl 2 •4H 2 O is 198.8129 ± 0.0003 g/mole. So us...

RosalieM wrote:I think there are 2 reasons for growing bacteria. The one where kids randomly collect germs from around the school, in which case the swiping is important and multible nasties grow.

Also, we're simply not allowed to do this anymore.

Na₂S₂O₃ (aq) + 2 HCl (dil aq) → 2 NaCl (aq) + S (coloid) + H₂O (l) + SO₂ (g)

It's known as a "clock reaction", because it leads to an abrupt colour change after a period of time has elapsed, based on crossing a concentration threashold.

Descication is definitely the way to go. You don't want to heat nitrates, or you'll end up with oxides, ... and nitrogen dioxide gas!

2 Mg(NO3)2 + heat → 2 MgO + 4 NO2 + O2

They are efficient, but keep in mind Laminar Flow units are not intended to be safety devices.

Air recirculates back to the user through many holes in a laminar flow, rather than being vented by a turbulent updraft.

They protect the work, not the user!