Support materials only that illustrate some possible contexts for exploring Science as a Human Endeavour concepts in relation to Science Understanding content.
Industries are encouraged to reduce their energy requirements in order to save money and reduce greenhouse gas emissions. One of the roles of chemical engineers is to consider the environmental, safety and economic aspects of energy use in the production of chemicals and to design and monitor chemical processes (ACSCH015). Green chemistry principles can be applied to industrial processes to reduce energy requirements; examples of these include recycling heat energy in chemical processes to improve efficiency and reduce cost and environmental impact, and redesigning chemical manufacturing processes to use less energy (ACSCH013).
Our bodies rely on the exothermic reaction of respiration to provide us with sufficient energy. Metabolism involves using the energy provided by carbohydrates, proteins and fats in our diet. Typically, food energy is determined based on heats of combustion in a bomb calorimeter, enabling foods to be compared based on the amount of energy they contain (ACSCH011). This information is provided as part of the requirements for processed food labelling in many countries to help consumers control their energy intake. In some instances this information is expressed as a proportion of daily average energy requirements, typically using a value ranging from 7500 to 8700 kJ (ACSCH012). However each individual’s body energy requirements varies depending on their gender, age, mode of activity and the environmental conditions they live in, so an average value may provide limited guidance.
A significant majority of the energy used for production of electricity, transport and household heating is sourced through the combustion of fuels. Fuels, including fossil fuels and biofuels, can be compared in terms of efficiency and environmental impact, for example by calculating the amount of carbon emissions produced per tonne of fuel used (ACSCH015). Decisions about which fuels to use can reflect social, economic, cultural and political values associated with the source of the fuel. For example, cultural values might inform the use of wood for heating houses; economic and social values might inform the use of crops for biofuel production instead of food production; and economic, social and political values might inform the use of brown coal rather than black coal, despite its being considered a low grade fuel (ACSCH012).