A supercool experiment

Safe­ty pre­cau­tions

Warn­ing! Only un­der adult su­per­vi­sion

Equip­ment:

• wa­ter;
• plas­tic bot­tle;
• plate;
• frozen grapes;
• fun­nel.

Step-by-step in­struc­tions

Fill a plas­tic bot­tle with wa­ter and leave it in the freez­er for 3 hours to ob­tain su­per­cooled wa­ter. If the wa­ter freezes, try again, de­creas­ing the cool­ing time. When the cool­ing time is up, hit the bot­tle against a ta­ble – the wa­ter in­side freezes in­stant­ly! Pour some wa­ter into a plate and put the plate into the freez­er un­til the wa­ter is com­plete­ly frozen. Take the plate out of the freez­er and pour some su­per­cooled wa­ter over it. An icy sta­lag­mite starts grow­ing! If a grape is low­ered into the su­per­cooled wa­ter, it emerges cov­ered with fluffy ice crys­tals.

Process de­scrip­tion

Liq­uid that has cooled down to a tem­per­a­ture be­low its freez­ing point is re­ferred to as “su­per­cooled.” The liq­uid’s state is rather un­sta­ble, so any out­er im­pact (like hit­ting it against a ta­ble, or putting a grape into it) caus­es it to freeze. These out­er im­pacts re­sult in the for­ma­tion of crys­tal­liza­tion nu­clei – seed crys­tals (of ice, in our case), which give rise to big­ger crys­tals, and the wa­ter freezes with stun­ning ra­pid­i­ty.

Per­form more su­per­cool and safe ex­per­i­ments with MEL Sci­ence!