“Normal high school chemistry curriculum standards (experimental)” advocate [1]: to enhance students subjectivity, so that chemical study and daily life, through laboratory-based inquiry activities into student learning styles; play the creativity of teachers, through courses and the development of teaching materials to promote the professional development of teachers. Based on this request, the chemical class student activities designed to fully close to both the student life, meet the student’s cognitive level and the teaching practice, guide the students hands-on activities to explore and think about; but also reflects the professionalism of teachers, based on the lessons creative use of standard content of teaching materials, development of new teaching resources to enhance their teaching and research capacity of teachers. This reference to foreign [2] the literature in combination with the specific conditions of China’s secondary schools to design life of these cases the use of common items to approximate measurements and compare the sugar (carbohydrate), and peanut oil (fat) in the case of calories in student activities to enhance students of different food calories understanding of the differences in order to reflect the basic concept of the new curriculum.

The background of an activity design

With the continuous improvement of people’s living standard, food nutrition and safety issues is receiving increasing attention, which “contained in the calorific value of different food how much?”, “How to control calorie intake and prevent obesity?” Is the life, widespread topic of concern. The body of calories consumed daily activities comes mainly from carbohydrates, fats and proteins, in food and energy is usually measured in calories, a card is equivalent to 4.184 Joule, 1 mL of water can rise 1 ℃. The calories in food is equivalent to 1000 cal or 1 kcal, not all food in the process of combustion or metabolic energy released is the same. Different food contains fat, protein and carbohydrates in different, of course, calories also have some differences. Reduce the intake of 14 kcal per day calorie foods, can make weight loss 1 pound (about 0.454 kilograms). For most people, to reduce 1 pound body weight every 37 days can extend the life span, meaning that a daily reduction of 1 kcal of food intake can extend life of 2.5 days. This activity through the burning of sugar and vegetable oil heated to a quality of water, and then by measuring the temperature rise to calculate and compare the two contains more calories, this activity for high school chemistry curriculum standards in the optional module “Chemistry and Life” in ” Theme 1 Chemistry and Health “of the” Understanding food on human health significance of common organic compounds [3] “the content of classroom teaching, through the activities, students are aware of carbohydrates and fats contained in the heat value of the difference, which led to the students for their own health concerns, the formation of a correct nutrition concept, to develop good eating habits. In the event the students will each food by measuring the combustion heat generated when water temperatures rise to two kinds of degrees to measure the energy of different food.

2 Principles of activity design

Fat contains more energy than carbohydrates, fat and carbohydrates were oxidized to carbon dioxide and the final water, per gram of fat contains more carbon atoms, so each gram of fat burning is about the energy released per gram of carbohydrate 2 times (carbohydrate production of heat is about 4 kcal / g, fat generates heat of about 9 kcal / g). Activities, grouping students to take a certain quality of burning sugar and peanut oil, heating a pop can filled with water methods; and then measure and record the temperature changes, the final adoption of Q = CpmΔT [where Q, said the energy (cal), Cp is the water specific heat (1 cal / g ℃), m is the quality of water (g), ΔT that the changes in water temperature (℃)] calculated Q value, and compare their differences in heat. As the activities are carried out in non-adiabatic systems, system and environment have a certain energy exchange, heating during the heat have lost. At the same time the heat foods are digested in the body, when released, the method of burning the results with the actual values subject to error, so this activity can only be an approximation determined. The event can also be used for rough measurements or comparison with other foods (such as fries, cashew nuts, peanuts, popcorn and various puffed food, etc.) of the calories in order to guide the students in peacetime control of heat in the diet should be noted that the value of food intake.