Australia's Science Forum

Can anyone give me advice as to how to dispose of agar mixed with silver nitrate which has been poured into plastic petri dishes and then had a strip of zinc placed into the mix. Can I bag and bin them? Or do they need specialist attention?

Lyn.

Which prac is this? Do share, I would like to know. Do not know the answer though. How about we road test new servic;e Science Assist

Jazz wrote:Which prac is this? Do share, I would like to know. Do not know the answer though. How about we road test new servic;e Science Assist

Sounds like Pearson Science 10, 4.2.1: Investigating a Metalic Element.
Mix 0.3g silver nitrate in 40mL distilled water, heat on hotplate, add in 0.5g agar-agar, set in a petri-dish with a strip of zinc in the center.

Ensure the teacher follows the instructions to leave it in a dark place. Not on the window sills... And makes sure the students set the agar into the smaller dish, and not the lid...

... ...

Anyway...

Silver should form crystals on the surface of the zinc. Scape it off and add to your heavy metal residue collection. Reuse the cleaned zinc strips.

Without nutrients, the agar will be mostly sterile. It's quite toxic after all. Melt it and add some sodium carbonate to form ZnCO3 and AgCO3. Spread the melt onto a tray to set then leave in sunlight to dry out. Then add the dried sheets to the HMR collection.

...phew Graham, that is a lot of effort. I must admit I would probably wrap up the stuff in newspaper and bin it for landfill, right or wrong!

Thanks for the advice Graham. I kinda figured that if I was looking at these grotty agar plates wondering what I should do with them then there must be others like me who needed the question asked. Another little piece of information to add to the very long list of things we should know.

Thanks again,
Lyn.

Is this a national curriculum prac??
We are about to write programs for yr7 and 9 for next year.

The blurb on the inside cover of Pearson Science 10 says that the textbook has been written specifically for the Australian Curriculum. I take it to mean the national curriculum.

Lyn.