How to freeze a beaker to a cork stand

How ammonium nitrate interacts with water and ice

Even Elsa would envy this cold “trick”!

Safe­ty pre­cau­tions

Per­form this ex­per­i­ment only un­der adult su­per­vi­sion.

Reagents and equip­ment

  • beaker with a thin bot­tom;
  • cork stand;
  • wa­ter;
  • crushed ice;
  • am­mo­ni­um ni­trate;
  • hot wa­ter.

Step-by-step in­struc­tions

Drip sev­er­al drops of wa­ter onto a cork stand. Place a beaker on the wet area and add some crushed ice and am­mo­ni­um ni­trate. Mix thor­ough­ly. Af­ter 5 min­utes, you will no­tice that the cork stand has frozen to the base of the beaker.

Pro­cess­ de­scrip­tion

When am­mo­ni­um ni­trate is added to ice, it low­ers the ice’s melt­ing point. At the same time, am­mo­ni­um ni­trate dis­solves in wa­ter and ab­sorbs heat, not only from the beaker but also from its sur­round­ings. The wa­ter on the cork stand thus cools and freezes the beaker to the cork stand.

A sim­i­lar ex­per­i­ment is in­clud­ed in the “Ther­mal ef­fects” kit from the MEL Chem­istry sub­scrip­tion.