Precipitation reactions: I am looking for precipitate reactions that have the least impact on the environment but are also dramatic. Do you have any suggestions?

Precipitation reactions: I am looking for precipitate reactions that have the least impact on the environment but are also dramatic. Do you have any suggestions?
Microscale Chemistry: Can you provide some information on microscale chemistry please?
Biology Depth Studies: Can you suggest ideas for (NSW) Depth Studies in biology?
Acetone and polystyrene foam: Is it suitable and safe in a primary school to conduct the activity in which a foam cup is “dissolved” in acetone?
Biodiesel: Do you have a method or advice that you can recommend for making biodiesel? I am concerned about the safety and waste disposal aspects.
Hydrogen peroxide storage: I have stored H2O2 in the fridge in the Chem Prep room for years but recently I have been part of discussions that say this should never be the case
Bacteria in yoghurt: Are yoghurt strains of bacteria suitable for use in schools? Are they safe to use in the biology practical “What causes Yogurtness”?
Disposal of agar containing silver nitrate: How should I dispose of an agar plate containing silver nitrate? It was used to create crystals with a piece of zinc.
Safety showers & eye washes: We are a very small regional school. We are after a SOP & risk assessment for safety showers and eye washes to use as a guide to write our own.
Container for sodium metal: We have sodium metal in the original container from 2008.