Alginate worms/polymers

[nickykinz]

I have been having a play using Gaviscon instead of sodium alginate to make alginate worms. It seems to work really well but I am having an issue. In both of the pracs I have it says to make a saturated solution of NaCl and that when you drop the alginate worms into it they will dissolve. Mine don’t dissolve. They have been sat in the salt solution since Friday as I have been off sick and they still look exactly the same as they did on Friday. Has anyone done this part of the prac and did it work?

[RosalieL]

I realise this is an old question - just wondering if anyone has made worms this way recently and what version of gaviscon works best? Do you use liquid straight from the bottle? Diluted? Or make solutions from the tablets? I've only just discovered this prac today so I'm looking at giving it a go. Sodium alginate is quite expensive!

[Marama T]

Sodium alginate is expensive but buying it in Gaviscon may be a false economy. We bought 100g and it's lasted several years.

[RosalieL]

Sodium alginate is expensive but buying it in Gaviscon may be a false economy. We bought 100g and it's lasted several years.

Thank you for your response. The recipe I saw required 20g/L which from a supplier worked out to be over $8 per class if they had a litre to split between students. Gaviscon doesn't work out as cheaply but I don't have to wait for freight to get it. I'd probably get sodium alginate for next year. I ducked out to the chemist so I'm going to have a play with it and let the teachers use it tomorrow if it works.

[RosalieL]

Does anyone know the best (cheap price, fast delivery) place to get sodium alginate and calcium lactate? There are a few places on ebay that sell both in a set but they don't have very good descriptions, just weight totals (eg 100g but is that 50g per packet or 100 per packet?) The experiment calls for 1g of sodium alginate and 5g calcium lactate per group so I'd still need to buy more of the calcium lactate separately. Ebay and Amazon are sending me crazy

[nickykinz]

I don't think you need to use calcium lactate. I have always just used calcium chloride. I think it just needs to be a calcium salt.
Last time I bought sodium alginate I got it from a place called Purely Black but they don't seem to sell it anymore. But you might find it easier to find a supplier if you are only looking for the sodium alginate without the calcium lactate. Food places sell it
https://www.melbournefooddepot.com/buy/ ... 40g/A00108

I know Westlab sell it. It is more expensive but if you are ordering other things it may work out just as cheap because of free delivery.

[RosalieL]

I ended up getting the sodium alginate off ebay and I've got calcium chloride on hand already. Apparently it only matters if you're actually going to eat it because the calcium salt you use can change the flavour. I did a trial of the prac they wanted to do as an assessment and I couldn't even get it right so they're just going to do it for fun and picked something different for the assessment task.

[bigmack]

Is this like the bobba balls ? Think they used fruit juice and Sodium alginate , then chill it and then drop it into Calcium Chloride with a syringe .

[RosalieL]

Yeah like that but they wanted big balls of water to be like bio friendly water bottles, so the plan was to have the students make the balls and then test how strong they were, but making the bigger balls (teaspoon/tablespoon sized) was really tricky! I'm sure with some practise it would become easier but it would take longer to develop that skill than the time they had for the experiment...