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From Marilyn Martin at GL Senior College, Forster:

Marilyn has discovered that small freezer bags work as well as dialysis tubing in the diffusion prac starch & Iodine. Students fill a corner of bag with a small amount of starch, tie a knot in the end of bag and immerse in water with Iodine sol'n added - works a treat much cheaper than tubing!!!

Well done that is a great idea
Will try it next time cheaper and if they put a hole in one just give them another.

Thanks that is a good idea. Well done.

Definitely going to try that one.

The bags would be easier to tie than the dialysis tubing too, making it easier all round. Looking forward to trying it!

I'ts a very quiet day here so I have just made up a small amount of starch solution and tried it in a freezer bag.
Works a treat

Now to convince the teachers. I have several who like the "real thing" not cheaper options. It has the potential to save a lot of money as we go through a roll of dialysis tubing each year!

Thanks for the tip. That is why this site is so great.

Wendy

I have not had a chance to try this yet. But does it also work the other way. Think it is starch in the bag, iodine in the beaker????????????????? To show the molecular movement.

i tried this last week.
I put starch solution in the bag, iodine in the water in the beaker and had good results after an hour.
I took photos, so will upload it if you like.

HT said that we are to use sandwich bags for jnr pracs and save the dialysis tubing for snrs and prac exams.

The teachers were not aware of how expensive the tubing was, til i pointed it out!

What a great idea, will definitely be giving it a go.

Coxy.....thanks for posting on Chemtalk, & also please pass on a big thankyou to Marilyn

I shared the freezer bag idea with a bunch of Adelaide labbies at a meeting last night & they al loved it!