help

[invited60f3274]

i have a quetion why when we want to presipit a compose we scrash the glass
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[invite87071598]

hi sara,

you can also stir the solution, or drop an already cristallised small bit of the compound you want to precipit. the objective is to create a perturbation in the solution in order to start the cristallisation.

cordially

[invite83d165df]

it seems that, when you scratch the glass, you create some tiny glass particules. These particles, of very irregular forms, are sites where molecules can hang. And when a certain number of molecules hang tear each other, they precipitate.