Australia's Science Forum

Does anyone out there have an alternative to saliva that works for the Year 11 Biology prac -
Effect of pH on Enzyme Action. It's from the text Biology in Context- The Spectrum of Life.

If anyone has any ideas I'd love to hear them.

Thanks

Instead of using sulfuric acid I use 0.5 or 1M sodium sulfate and a few drops of universal indicator soln.

Add the sulfate and universal indicator before you fit the electrodes, then fill from the top as usual. Shows pH levels at each electrode and so far I've found this way works well.

Cheers

That prac is also in the old Core Biology Prac book - Cells 1.16. We haven't done that one for a while but I remember it worked well. The raw liver didn't smell but was pretty messy to clean up. The smelly part was boiling the liver for the comparison. :-| It also uses 3% H2O2 and MnO2 as the contro...

I grew up in Sydney and even I used to eat the delicacies mentioned (couldn't come at tongue though). But that was in a past life thank goodness.

The board outside a butcher shop I use has a sign that says:

Sheep Brains $2.50 a box
INCREASE YOUR IQ!

Cheers
Judy

Try washing them in Pyroneg & use a pipe cleaner to clean the inside of the glass tube.
That's what I use & it works pretty well.
Any that can't be cleaned easily get chucked.

Cheers
Judy

Hi Labman,

The equipment you need is sold through Serrata
It's called Trajectory Apparatus.
#1014008 on p53 of 2006 catalogue.

Cheers

Hi Rae, We got a quote last year to have our chem store shelving replaced with chemical resistant laminate & even though it's a small room the quote came to $14,000. In the end we got another builder who made new shelves & painted them with chemical resistant paint (Dulux 2 pack). He had eno...

Hi fibreweb,

We purchased some white out thinner a couple of years ago.
it turned out to be 1,1,1 - trichloroethane so that may be your best bet.

Good luck
Judy

Mercury has a red dot so teacher use only.

We still use mercury thermometers in the chem lab & I use them in the Prep Room
but the other students use the green spirit ones.

Cheers

Hi Di,

I've sent you a personal message.

Judy

Hi Mother, Did you calibrate the meters before you took any readings? I use buffers of pH 4,7 & 10 & they need to be calibrated before for each class uses them. We also have electrode storage solution for when they're not in use. The only other thing I can think of is that the batteries may ...

Hi Lizzieb,

Does Sudan 111 really work as an indicator of cellulose?

I thought that it was used as a fat stain only.
Can you give me more info please.

Cheers
Judy

We still use phloroglucinol to stain lignin. Mix 2.5g phloroglucinol in 100ml of 95% ethanol. Add conc. HCl until ppt forms. It can also be used as a reagent for pentosans - 3g in 100ml ethanol. Lycopodium are the yellow spores from the club mosses.We don't use it anymore. I think it may have been u...

I have much the same recipe as Jojo only 8.5ml water is used instead of 9.5ml. The ppt. should persist on shaking. Pink/purple indicates a positive result. An alternative is Cross & Bevan's reagent: 2 parts conc. HCl to 1 part zinc chloride crystals by weight. (From my "bible" - A Hand...

If you are trying to see if Dettol inhibits bacterial growth it might be easier to use spreaders to cover the whole plate with the broth & then place filter paper discs soaked in the antiseptic on the surface of the plate.(placed evenly) We test 4 antiseptics at a time using 2 different types of...

There's a place called Labstaff that I presume is still trading.

They supply workers for all sorts of lab work. A friend of mine worked in a pathology lab in Sydney & they used to hire people through Labstaff.

Sorry I don't have any further info.

The recipe I use is as follows: Methyl orange - 1.0g Indigo carmine - 2.5g Dissolve powders in 1L distilled water. Filter before use. pH range 2.9 (purple) - 4.6 (dark green). The colour change is easier to see than Methyl orange but the shelf life isn't that long. Generally worth the effort of havi...

We also had our chem store rebuilt last year & had a BOS inspection. The builder used MDF but then coated the boards with chemical resistant paint. So far so good. The paint is called Dulux Luxepoxy 4 White primer & Luxepoxy 4 Finish ( 2 pack epoxy). He also fixed perspex edging to each shel...

From what I understand Tes- tape isn't manufactured anymore. We also use Clinistix or Uristix, also available from Sthn Bio.
Uristix have 2 pads - one for protein & the other for glucose which we use when the students are doing food tests.They work well & it saves having to use Biuret.

Hi Pommie,

Did you know you can buy burette brushes? I got mine from Q Stores some time ago now so I'm not sure if they still keep them.

If you can't find one I'll send you one of mine.

Cheers