making soap

[pkij]

I have a year 10 prac to make soap, using veg oil, ethanol and 6M NaOH. The mixture needs to be heated for 30 minutes in a water bath but another recipe I found said to heat in a beaker. I will try it myself today but I was wondering if anyone has done this prac, how it worked best, and how dangerous it may be (I have some reservations about 6M NaOH and year 10's!! )

Thanks
Pilar

[Labbie]

Here is NSW and the CSIS we could not use 6M Sodium Hydroxide, with Year 10's.

The book said years 7-10 could use 2M, otherwise should use Soluitions of 1M only. But I am not too sure what goes on in QLD.

Regards

[labman]

Hi Pilar,
We have just finished doing this prac, the labs are full of weird soap samples(they test it). We use 6M NaOH, but I only have Yr 11 and 12 here, and the teacher dispenses it from the fume cupboard.
Our method is to mix the oil, alcohol and NaOH in a 100ml beaker, then place that in a 250ml beaker, with enough water for heating purposes in the 250ml beaker. The students place that on tripod, over bunsen flame for 30 minutes, stirring the contents continuously. From there they have several other processes they go through, but I'm assuming it's only the heating procedure you were unsure about. I'm happy to fax you a copy of the whole prac if you need it , or just want to compare.
Cheers,
Lisa

[pkij]

Thanks Lisa that would be most appreciated . I did think it would be a good idea for the teacher to dispense the NaOH, and yes I was a bit concerned about the heating bit. My fax here is (07) 47435013.

[smiley]

Hi Pilar,

We've done the same prac here. Two things I've done to reduce the risk are: 1) Measure out the NaOH into individual flasks, and the teacher dispenses it from the fume cupboard(then no-one is messing around with strong NaOH and measuring cylinders, except me!), & 2) I have purchased a set of individual electric hotplates @ approx $25 ea for pracs like these, as well as when we have to heat alcohols. The hotplates are available from discount shops like Crazy Clarks etc. I actually negotiated a good deal with an electrical store that gives a big discount if you pay cash. They wanted to look "community minded" and we gave them a "Thank you" on letterhead - a win/win situation.

Apart from that, the results of this prac seem to be largely dependent on whether the moon is in the 4th quarter of Venus, and whether students' auras were in tune with their environment on that day! In other words, our results ranged from lovely, identifiable hard soap, to a form of soft handwash, to complete disaster. Sounds like lots of student experiments doesn't it?

Good Luck. K

[Xenon]

The CSIS appendix D guidance notes allow years 7-10 to use solid NaOH for soap and paper making (under close supervision). 6M is user code Teacher only.

Xe, SD, KOPR

[KarenN]

Does anyone have any other simple soap recipes (not using high concentration NaOH) ? tHANKS

[rosiegbh]

Hi,
We have made soap for a Year 10 enrichment day this year with some success but the recipe we used came from "The Laboratory" a science manual for schools.

I don't think you can make it without sodium hydroxide but we used 100ml 4M NaOH a little less toxic plus 10 dessertspoons dripping and 100ml saturated sodium chloride solution.

I pre poured the NaOH and stressed the handling of it. It is a little trial and error plus plenty of time to boil, not a prac to attempt in one lesson.

Rosemary