Chemical (silicate) garden

When salts of sev­er­al met­als are added to a so­lu­tion of sil­i­cate glue, mul­ti-col­ored “sea­weed” forms.

Reagents and equip­ment:

• sil­i­cate glue;
• dis­tilled wa­ter;
• salts of cobalt, iron, nick­el, man­ganese;
• a small aquar­i­um.

Step-by-step in­struc­tions

Mix the sil­i­cate glue and wa­ter in a ra­tio of 1:1 by mass. Place a small amount of each salt in the so­lu­tion. Ob­serve how beau­ti­ful mul­ti­col­ored "sea­weed” grad­u­al­ly grows out of the salt crys­tals.

Pro­cess­es de­scrip­tion

Sil­i­cates of many met­als are in­sol­u­ble in wa­ter. The glue used in the ex­per­i­ment con­tains rel­a­tive­ly sol­u­ble potas­si­um and sodi­um sil­i­cates. When salts of 2-3-va­lence met­als are added, an ex­change re­ac­tion be­gins, and a film of their in­sol­u­ble sil­i­cates forms around the salt crys­tals. Wa­ter can pen­e­trate this film. In­side the film, the con­cen­tra­tion of salt is high­er than out­side, so a dif­fer­ence of os­mot­ic pres­sures aris­es, and the wa­ter flows into the sil­i­cate shell. This caus­es the shell to ex­pand and dis­in­te­grate, the salt and so­lu­tion come into con­tact again, and a new film of sil­i­cate is formed. In this way, the “sea­weed” grows. The col­or of the “sea­weed” de­pends on the met­al: blue for cobalt, pink for man­ganese, green for nick­el and brown for iron.

Safe­ty pre­cau­tions

Wear pro­tec­tive glass­es and gloves. Fol­low gen­er­al safe­ty rec­om­men­da­tions. Chem­i­cal ex­per­i­ments must be car­ried out in full com­pli­ance with the leg­is­la­tion of your coun­try.

Warn­ing! Sub­stances of this ex­per­i­ment are tox­ic and high­ly dan­ger­ous for your health. Do not try this at home. Only un­der pro­fes­sion­al su­per­vi­sion.