Agitation and Crystallization A Practical Laboratory Experiment ARTHUR W. DEVOR Adelphi College, Garden City, New York
MANY students like to do experiments which can be applied to their daily activities. The experiment described here is excellent for girls, especially home economics students, and i t works very well in demonstrating a practical application of rapid crystallization caused by agitation. Water and sugar (sucrose) were mixed together in two small beakers, each containing 10 ml. of water and 10 g. of sugar. ' The mixtures were carefully boiled until the sugar was all in solution. A few crystals of sucrose were then dropped into each beaker. One mixture was vigorously stirred for 10 to 15 minutes, then both were set away in the student's locker. The students
noticed the milky appearance due to small crystals as they stirred the mixture. After a week, they observed the difference in appearance of the two mixtures and were asked to taste each and explain the reasons for the difference. Then they were asked why cake icing and certain candies are "beaten" or vigorously stirred before pouring them out of the cooking utensil. 'When answering the questions the most general observations, as a result of tasting, were that the mixture was sweeter and less "sugary" or "sandy" when stirred. Nearly every student could explain the reason for such observations as well as explaining the necessity of stirring the foods as mentioned above.
