Artificial jellyfish

Safe­ty pre­cau­tions

Warn­ing! Only un­der adult su­per­vi­sion.

Equip­ment

• sodi­um sil­i­cate;
• so­lu­tions of cop­per(II) chlo­ride and nick­el(II) sul­fate,; *Petri dish;
• pipettes.

Step-by-step in­struc­tions

Add a few drops of cop­per(II) chlo­ride and nick­el(II) sul­fate so­lu­tions to a so­lu­tion of sodi­um sil­i­cate. The droplets don’t spread through the sodi­um sil­i­cate, but rather re­main on the sur­face, form­ing neat-look­ing ar­ti­fi­cial jel­ly­fish.

Process de­scrip­tion

Due to the high vis­cos­i­ty of the sodi­um sil­i­cate so­lu­tion, the droplets don’t spread over its sur­face or mix with it, but in­stead splash and spat­ter some­what like paint cap­sules fall­ing on as­phalt. At the same time, re­ac­tions be­gin be­tween the com­pounds in the droplets and the sodi­um sil­i­cate so­lu­tion:

Cu­Cl₂ + Na₂­SiO₃ → Cu­SiO₃↓ + 2Na­Cl

NiSO₄ + Na₂­SiO₃ → Ni­SiO₃↓ + Na₂­SO₄

Cu­Cl₂ + Na₂­SiO₃ + H₂O → Cu(OH)₂↓ + 2Na­Cl + SiO₂↓

Such re­ac­tions pro­ceed rel­a­tive­ly quick­ly, yield­ing a film of in­sol­u­ble com­pounds be­tween each droplet and the sodi­um sil­i­cate so­lu­tion. Thus the droplets do not spread, in­stead be­gin­ning to re­sem­ble jel­ly­fish.

A sim­i­lar ex­per­i­ment is in­clud­ed in the MEL Chem­istry sub­scrip­tion!