Scientific ice cream

Want to learn the fastest and eas­i­est way to make ice cream? Check out this fun ex­per­i­ment!

Safe­ty pre­cau­tions

Warn­ing! Only un­der adult su­per­vi­sion. Be sure to use oven mitts.

Equip­ment

• two re­seal­able bags of dif­fer­ent sizes;
• crushed ice;
• salt;
• 2 tbsp sug­ar;
• 1 tsp vanil­la pow­der;
• 300 mL milk;
• 200 mL cream;
• oven mitts.

Step-by-step in­struc­tions

Pour 300 mL of milk and 200 mL of cream into a small re­seal­able bag. Add sug­ar and vanil­la pow­der to taste (rec­om­mend­ed: 2 tbsp sug­ar, 1 tsp vanil­la pow­der). Seal care­ful­ly. Pour some crushed ice and salt into a larg­er re­seal­able bag. Put the small­er bag into the larg­er bag, seal, and shake for 15 min­utes. (Be sure to wear oven mitts while shak­ing the mix­ture so as not to chill your hands!) Your ice cream is ready!

Process de­scrip­tion

When the ice melts, the salt grad­u­al­ly dis­solves in the form­ing wa­ter. This dis­so­lu­tion process re­quires en­er­gy (heat), and this en­er­gy is tak­en from the bag of milk and cream. The in­gre­di­ents freeze, turn­ing into ice cream. Pro­cess­es in­volv­ing the ab­sorp­tion of heat from the sur­round­ing en­vi­ron­ment are called “en­dother­mic.” A 3:1 cool­ing mix­ture of ice and ta­ble salt can yield a tem­per­a­ture of about -21 °C. In this case, it is best to use fine­ly-ground ice and salt to in­crease their con­tact sur­face area.

More sim­ple and ed­u­ca­tion­al ex­per­i­ments are wait­ing for you in the MEL Chem­istry sub­scrip­tion!