The science of applying scientific and mathematical principles to solve real-world problems. Engineers work in many different industries and companies, from engineering firms to environmental agencies. They are usually involved in the design, testing, production or maintenance of materials, structures, machines, devices, systems or processes. At the front end of a problem, they analyze the situation and design a solution to meet a need. In the middle of the process, they oversee prototype production and perform tests. After a solution is implemented, engineers make adjustments for efficiency, improve performance, supervise operations and troubleshoot problems.

Engineering positions usually require a four-year college degree in an engineering discipline and successful completion of the Fundamentals of Engineering (FE) exam. Normally, after four years of professional experience, engineers can take the Principles and Practice in Engineering exam in their chosen discipline to earn a practicing engineer (PE) designation. Licensed engineers earn higher salaries and may qualify for senior positions.

Communication and documentation are an important part of an engineer's job. An engineer collaborates with drafters, manufacturers, marketers, salespeople, clients and business executives. In each stage of the design, testing and implementation process, engineers keep careful records to ensure the reproducibility of the process and to facilitate easy adjustments. They must also keep track of the budget and contribute to project proposals. Engineers use a variety of computer programs including drafting programs and design software. They must be highly computer literate and comfortable adapting to new technology.

Most engineers specialize in a specific field such as mechanical, civil, biomedical, materials, chemical, environmental or aerospace engineering. Engineers design solutions for problems of many scales, from the atomic to the galactic level.