#1 Science Forum For Lab Technicians

Yeah we normally do starch in the dialysis tubing and lugol's iodine in the water. The iodine goes in but the starch doesn't come out. The only one group started to turn black.

Does anyone have the prac for glucose osmosis? The one where glucose goes in the tubing and distilled water in the beaker, then test the beaker water for glucose at the end with benedicts solution? The only ones I can find online have the starch and glucose combined (which I will suggest we use for ...

PS bigmack - how did you just happen to work this out??

I originally joined in 2007! hahaha now I feel old...

Next time try soaking them in metho for 24 hours. It firms them up a bit. It's not a perfect solution to the mushiness but it's better than dishing up a pile of goop.

We use them for rates of reaction - surface area. So they do one whole, one in quarters, one completely crushed and they time how long each one takes to dissolve.

Marama T wrote: 23 Feb 2026, 06:42 We use effervescent denture cleaning tablets instead of Alka-Seltzer. Much cheaper.

I tried that and the teachers said the end point was too hard to see

I hadn't thought about it that way !! I might just stick to purchasing

Random Friday morning thought... Has anyone ever considered using a tablet press to make your own "alka-seltzer" tablets for pracs? So instead of spending a small fortune each year on tablets (we've recently discovered the help@hand electrolyte tablets work well which are a bit cheaper) and then ...

I ended up finding them in Kmart $6 for 100pk. It must just be hit and miss when I go looking...

Where do you all buy your balloons in bulk? I'm finding supermarkets are getting so expensive and only 20 balloons at a time.

A mini ripple tank sounds interesting! What a shame you missed the farm talk though...

So, we've just done this one again this year. The teacher did it in beakers but 3 beakers broke in the process... We are now looking into induction hotplates and saucepans. Not just for this one prac, but there have been a few times the teachers have wanted hotplates instead of bunsens for whatever ...

5 years from when it was last "updated" on the actual SDS produced by the manufacturer

We don't have one, but I would recommend looking at the Go Direct DO sensor from scientrific. They connect to devices via bluetooth and recharge via usb-c cables. We have other sensors from the Go Direct range and they are so easy to use once you play around with the free software for graphing etc ...

I have the same as bigmack but in googlesheets except I only have current green/not current red. I might just add in an orange one next time I'm working on it! I think that's a great idea.

yikes! I would be giving out a big tub and measuring cups/beakers and finding a bulk supplier/catering supply company near you! Although then I'd probably be the one dealing with the mess afterwards so maybe not...

Has anyone used the boon grass drying racks for glassware? They are designed for baby bottles. We don't have anywhere in the labs for rinsed glassware and it all just gets put into tote trays. I was thinking this might solve the problem as it catches the water in the tray but still allows the ...

I'm glad it's not just me! I decided to go with non-hazardous as because they're both saying non-DG for transport then I'm storing with the other non-hazardous chemicals anyway... and I have links to the SDS on my register to prove that they are non-hazardous so I figure I'm covered!

I have the same problem with two different brands of ammonium thiocyanate...

Edit - I read one of the SDSs wrong. They both say Hazardous but not DG, but the confusion in the above post still stands.