Civil engineering is a professional practice that involves designing and developing infrastructure projects, such as buildings, roads, bridges, and water supply systems. Civil engineering courses teach students to apply mathematics and scientific knowledge, particularly physics, to real-life situations and problems that arise from creating and maintaining structures, taking into account environmental, financial, legal, and ethical considerations. Civil engineering is a combination of many scientific specialisms, including mechanics, hydraulics, geotechnics, materials science, and statistical analysis. Civil engineering degrees are typically three or four years in length and feature a mixture of lectures and lab work, with an emphasis on working within a team. Civil engineering electives ensure that students have a deep understanding of environmental, geotechnical, structural, transportation, and water resources engineering. Civil engineers may work for government agencies or consulting and construction firms that deal with private or government clients. Civil engineering requires knowledge of math, physics, chemistry, and other technical subjects, and many civil engineers have a bachelors degree. Civil engineering software, such as Autodesk, is also important for civil engineers doing design work.