Engineering

Next generation of greenhouses may be fully solar powered

Many greenhouses could become energy neutral by using see-through solar panels to harvest energy—primarily from the wavelengths of light that plants don't use for photosynthesis. Those are the findings of a new modeling ...

Energy & Green Tech

Wearable health tech gets efficiency upgrade

North Carolina State University engineers have demonstrated a flexible device that harvests the heat energy from the human body to monitor health. The device surpasses all other flexible harvesters that use body heat as the ...

Energy & Green Tech

Instant hydrogen production for powering fuel cells

Since the Industrial Revolution, the environmental impacts of energy have posed a concern. Recently, this has driven researchers to search for viable options for clean and renewable energy sources.

Energy & Green Tech

Stability assessment and reporting for perovskite photovoltaics

Improving the long-term stability of perovskite solar cells, which is crucial for the use of this pioneering technology—this is the topic of a paper published in the journal Nature Energy by an international research team, ...

Energy & Green Tech

France shuts oldest reactors, but nuclear power still reigns

France will start closing its oldest atomic power plant on Saturday after 43 years in operation, the first in a series of reactor shutdowns but hardly a signal the country will reduce its reliance on nuclear energy anytime ...

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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