Engineering

Creating smart, resilient cities for a sustainable future

The vision to create sustainable urban spaces is becoming a reality in several European cities, including Rotterdam, Umea and Glasgow. Thanks to the EU-funded Ruggedised project, Rotterdam is developing and implementing various ...

Robotics

A flexible microrobot that can survive almost any deformation

An International research team led by Dr. Oliver Schmidt, working at Chemnitz University of Technology (TU Chemnitz) and Leibniz IFW Dresden has recently developed a microrobitic system with a wide range of possible applications, ...

Energy & Green Tech

Uncertain climate future could disrupt energy systems

Extreme weather events—such as severe drought, storms, and heat waves—have been forecast to become more commonplace and are already starting to occur. What has been less studied is the impact on energy systems and how ...

Energy & Green Tech

Major new study charts course to net zero industrial emissions

A major new study by an interdisciplinary team of researchers finds that it is possible—and critical—to bring industrial greenhouse gas emissions to net zero by 2070. Published Sunday in Applied Energy, the study assesses ...

Energy & Green Tech

Sunny prospects for start-up's clear solar energy windows

A Redwood City, California-based tech startup has developed a glass window packed with transparent photovoltaic cells that it believes will revolutionize the way solar energy is harnessed.

Energy & Green Tech

Scientists tap unused energy source to power smart sensor networks

The electricity that lights our homes and powers our appliances also creates small magnetic fields that are present all around us. Scientists have developed a new mechanism capable of harvesting this wasted magnetic field ...

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Energy

In physics, energy (from the Greek ἐνέργεια - energeia, "activity, operation", from ἐνεργός - energos, "active, working") is a scalar physical quantity that describes the amount of work that can be performed by a force, an attribute of objects and systems that is subject to a conservation law. Different forms of energy include kinetic, potential, thermal, gravitational, sound, light, elastic, and electromagnetic energy. The forms of energy are often named after a related force.

Any form of energy can be transformed into another form, but the total energy always remains the same. This principle, the conservation of energy, was first postulated in the early 19th century, and applies to any isolated system. According to Noether's theorem, the conservation of energy is a consequence of the fact that the laws of physics do not change over time.

Although the total energy of a system does not change with time, its value may depend on the frame of reference. For example, a seated passenger in a moving airplane has zero kinetic energy relative to the airplane, but non-zero kinetic energy relative to the Earth.

This text uses material from Wikipedia, licensed under CC BY-SA