Make ice cream - metrically!During an unusually hot month in our non-air-conditioned school, I hit on the perfect activity to teach my students metric measurements - making ice cream! * I preview the activity by showing my students the ice cream recipe below that uses metric measurements. Then we prepare for our ice cream making by learning to use Celsius thermometers Celsius thermometer a centigrade thermometer employing the Celsius scale. The abbreviation 100°C should be read as 'one hundred degrees Celsius'. , metric rulers, graduated cylinders and beakers, and a balance. * I ask parents to notify me if their children have any medical conditions See carpal tunnel syndrome, computer vision syndrome, dry eyes and deep vein thrombosis. which would preclude eating homemade home·made adj. 1. Made or prepared in the home: homemade pie. 2. Made by oneself. 3. Crudely or simply made. Adj. 1. ice cream. * To prevent mishaps, I demonstrate the recipe before the students get started. Ingredients and Materials: vanilla vanilla, a plant of the genus Vanilla of the family Orchidaceae (orchid family). Vines of hot, damp climates, most are indigenous to Central and South America, especially Mexico, but are now cultivated in other tropical regions. flavoring (handle with care, because it'll sting if it gets in eyes), milk, sugar, 2 sizes of plastic zipper zipper Device for binding the edges of an opening, as on a garment or a bag. A zipper consists of two strips of material with metal or plastic teeth along the edges, and a sliding piece that interlocks the teeth when moved in one direction and separates them again when moved bags, ice. For a class of 30 students working individually, you'll need approximately 3 gallons of milk; a 5-lb. bag of sugar; one 1-lb, 10-oz. container of salt; 3 large bags of ice; and 2 bottles of vanilla flavoring. Student Directions: 1 Pour 1 ml. of vanilla flavoring and 110 ml. of milk into a plastic zipper bag that measures approximately 17 cm. by 17 cm. 2 Add 12 g. of sugar and seat the bag. 3 Hold a thermometer thermometer, instrument for measuring temperature. Galileo and Sanctorius devised thermometers consisting essentially of a bulb with a tubular projection, the open end of which was immersed in a liquid. against the zipper bag and record the temperature in Celsius. 4 In a second zipper bag (27 by 30 cm.), add 13 g. of salt and approximately 1,000 ml. of ice. 5 After making sure it's tightly sealed, put the smaller bag inside the larger bag. 6 Gently massage the bag until the mixture changes into frosty frost·y adj. frost·i·er, frost·i·est 1. Producing or characterized by frost; freezing. See Synonyms at cold. 2. Covered with or as if with frost. 3. Silvery white; hoary. 4. ice cream. This will take about five minutes. 7 Take the temperature of the ice cream and compare it to the first temperature reading. 8 Wipe the salt off the top of the small bag, open carefully, and eat! To extend the activity, we brainstorm ways to improve the flavor and texture of our ice cream, such as adding cream instead of milk and trying different flavorings. Students then work in groups to develop their own ice cream flavor, experimenting with the recipe by using different ingredients. When they discover a flavor they like, they come up with a name for it, design an ice cream carton, and present their creation to the class. |
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