This post was written by Amara Alexander, the 2019-20 Albert Einstein Distinguished Educator Fellow at the Library of Congress.
The days are getting longer and the breezes of summer are around the corner. The warmer weather brings summer vacations, water activities, and fun-filled adventures shared with friends and family. If you listen closely, you might hear the tunes of an ice cream truck roaming through the neighborhood enticing children and adults to buy the popular frozen treat.
Ice cream is not a new treat; Alexander the Great was believed to have snow and ice flavored with honey and nectar on occasions while former President Thomas Jefferson had his own recipe for ice cream.
How is this beloved refreshment made? What scientific principles support superior ice cream? Lots of interesting chemistry goes into making ice cream. The ice cream mixture begins as a liquid then changes states of matter into a frozen form, but can return to liquid when it melts. Ice cream is an emulsion—a combination of two liquids that don’t normally mix together. Instead, one of the liquids is dispersed throughout the other. Liquid particles of fat are spread throughout the mixture of water, sugar, and ice along with air bubbles.
In the photograph, the young men appear delighted to watch the production of ice cream, and making ice cream can be an exciting science investigation for your learners. Focus attention on the photograph and prompt learners to think about the process of making ice cream. What tools are being used to make the frozen treat? How long does it take to make ice cream? Select additional images from this set to pique students’ curiosity!
Although the creativity in making ices or ice cream has evolved, the main ingredients are the same: milk and sugar. In earlier recipes, egg whites were essential to the recipe, but in modern recipes egg whites are not used. Invite learners to compare and contrast older recipes to current recipes to identify the similarities and differences. Students may be intrigued by the older recipes of sherbet and chocolate ice cream. Encourage them to consider how many flavors of ice cream are there? List their favorite flavors of ice cream. What are the most popular flavors of ice cream across the globe? These answers may lead to further discussion or a research project focused on the history of ice cream. If time allows, try to recreate ices or ice cream.
An up and coming trend is making ice cream with liquid nitrogen. Liquid nitrogen freezes the ice cream almost instantly creating a creamy texture. There may be an ice cream stand near you selling ice cream made using liquid nitrogen. Ice cream is delicious and yet, scientific. Take a moment and enjoy the sweet treat during the summer.