Hy!
I have a question about ionic reactions (precipitation, color change).

I need to prepare a short experiment. It must be interesting without, dangerous chemicals and without warming. It will be performed by 14-year-old students. Anyone have any idea? Is the experiment on this connection a part of ion reactions? https://melscience.com/en/articles/egyptian-night-experiment-190418/?utm_source=FBpost_en&utm_medium=EgyptianNight190418_article_en
Thank you for any information.

Peroxide is some how dangerous. Yes there are ionic reactions.

Potassium permanganate and hydrogen peroxide or  citriate salt  or tartrate salt

 

https://www.google.co.uk/search?q=potassium+permanganate+reactions&source=lnms&tbm=isch&sa=X&ved=0ahUKEwix8qvLlfLdAhWKW8AKHZ94CFkQ_AUIDigB&biw=1366&bih=622#imgdii=Yn_vxGDDlbd5zM:&imgrc=aJIIOLEzliBGuM:

Calcium chloride with carbonates of sodium, potassium or other alkali metal carbonates. Forms calcium carbonate which is calcite. It is only a white powder, but much safer.

Iodide with lead is bright yellow but lead around children is typically frowned upon.

potassium Ferrous and Ferric cyanate make a dark blue when mixed, but that is not an easy precipitation reaction to use as an introduction ionic reactions.  It is more related to oxidation states.