14. Mathematics and resources Cambridge University Press  G K Powers 2013 Study guide Chapter 14

Water availability To predict the future of the world’s water resources we must interpret information, make comparisons and perform calculations in relation to water availability. Rainfall changes are occurring due to increased concentration of carbon dioxide in the atmosphere. Maximum volume of water in tanks is calculated by multiplying the area of the base by the height. Volume of water collected from a roof is calculated by multiplying the horizontal area of the roof and the depth of rainfall. HSC Hint – Volume of water collected from a slanted roof is less than the volume from a horizontal roof. Cambridge University Press  G K Powers 2013

Water usage Water usage is the use of water by households and industry, as well as for agricultural, recreational and environmental activities. Tables and graphs are used to present water usage. HSC Hint – Always check that conclusions gained from tables and graphs are reasonable. Cambridge University Press  G K Powers 2013

Dams, land and catchment areas To calculate the perimeter of land multiply the length on an aerial photograph by the scale. To calculate the exact area of land use the appropriate formula. Volume of a dam is estimated using Simpson’s rule. V – Volume of the dam h – Height or width of the equal parts Af – Area of the first line Am – Area of the middle line Al – Area of the last line Cambridge University Press  G K Powers 2013

Energy consumption The watt is the unit of power and is equal to one joule per second. Symbol for the watt is W. Standard prefixes such as milli, kilo, mega, giga and tera are then added. Energy is the rate of power per unit of time (kilowatt-hour – kWh). Running costs of an appliance is calculated by multiplying the energy consumption by the electricity charge. HSC Hint – Match the units of time for the energy consumption and the electricity charge. Cambridge University Press  G K Powers 2013

Sustainability Sustainability is a method of using resources so that the resource is not deleted or permanently damaged. BASIX or Building Sustainability Index is a scheme to regulate the energy efficiency of residential buildings. HSC Hint – Sustainable houses feature rainwater tanks, water-efficient shower heads, solar hot water, glazing and energy-efficient lighting. Cambridge University Press  G K Powers 2013