Can ice be hot?

No idea how to spend a cold win­ter evening? Have we got an idea for you!

Safe­ty pre­cau­tions

Per­form this ex­per­i­ment only un­der adult su­per­vi­sion.

Equip­ment

• por­ta­ble stove;
• heat-re­sis­tant glass;
• sodi­um ac­etate;
• watch glass;
• stick;
• plate.

Step-by-step in­struc­tions

Put a heat-re­sis­tant glass of sodi­um ac­etate on a por­ta­ble stove. Be sure to cov­er it with a watch glass to pre­vent too much wa­ter from evap­o­rat­ing. Heat the sodi­um ac­etate un­til it be­comes a trans­par­ent yel­low­ish liq­uid. Let cool to room tem­per­a­ture. If you toss a crys­tal or any oth­er ob­ject into the liq­uid sodi­um ac­etate, it will im­me­di­ate­ly be­gin to crys­tal­lize. You can even build a tow­er with liq­uid sodi­um ac­etate!

Pro­cess­ de­scrip­tion

Sodi­um ac­etate is a sodi­um salt of acetic acid. Most of­ten, it ex­ists as a hy­drate, bond­ed to 3 wa­ter mol­e­cules. It also pos­sess­es a cu­ri­ous prop­er­ty – when heat­ed, it dis­solves in the wa­ter present in its own struc­ture, yield­ing a su­per­sat­u­rat­ed so­lu­tion of sodi­um ac­etate. When the so­lu­tion cools, a crys­tal, a speck of dust, or even the touch of a fin­ger can start the crys­tal­liza­tion process. The re­sult­ing crys­tals have a beau­ti­ful nee­dle struc­ture and look like snow or ice. As the re­ac­tion re­leas­es a large amount of heat, this ex­per­i­ment is called "hot ice”.

En­joy more cool ex­per­i­ments with a MEL Chem­istry sub­scrip­tion!