Energy & Green Tech

A blast of gas for better solar cells

Treating silicon with carbon dioxide gas in plasma processing brings simplicity and control to a key step for making solar cells.

Energy & Green Tech

Charging electric cars up to 90% in six minutes

With Telsa in the lead, the electric vehicle market is growing around the world. Unlike conventional cars that use internal combustion engines, electric cars are solely powered by lithium ion batteries, so the battery performance ...

Electronics & Semiconductors

Radiative cooler that cools down even under sunlight

Now that autumn is upon us, there is a large temperature gap between day and night. This is due to the temperature inversion caused by radiative cooling on the Earth's surface. Heat from the sun during the day causes its ...

Energy & Green Tech

COVID-19 renewable energy response in Africa 'meager'

As of June this year, only three Africa countries, Burkina Faso, Kenya and Nigeria promoted the use of renewable energy to control the challenges COVID-19 triggered in the sector, a study says.

Energy & Green Tech

Open-source distributed generation market demand model

After years of development, the National Renewable Energy Laboratory (NREL) has released the open-source dGen model, marking a new era since the model launched in 2016. Public users can access model methodology and instructions, ...

Energy & Green Tech

Wind energy and wildlife share future in the skies and seas

A wealth of wind energy potential as well as rich and diverse networks of wildlife species can be found off the coasts of the United States. Coastal ecosystems range from beach dunes where turtles and birds nest, to the shallow ...

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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