Chameleon's tongue strike inspires fast-acting robots

Chameleons, salamanders and many toads use stored elastic energy to launch their sticky tongues at unsuspecting insects located up to one-and-a-half body lengths away, catching them within a tenth of a second.


New technique lets researchers map strain in next-gen solar cells

People can be good at hiding strain, and we're not alone. Solar cells have the same talent. For a solar cell, physical strain within its microscopic crystalline structure can interrupt its core function—converting sunlight ...

Energy & Green Tech

To rid electric grid of carbon, shore up green energy support

Cornell and Northwestern University engineers, along with a federal economist, have created an energy model that helps to remove carbon-generated power from the U.S. electric grid—replacing it with a greener, financially ...


Software helps planners design walkable cities

Walkable cities reduce traffic congestion, which causes around 3.3 million deaths and $121 billion in economic losses every year. But when architects are developing pedestrian-friendly neighborhoods, they often rely on trial ...

Computer Sciences

Modeling every building in America starts with Chattanooga

Buildings use 40 percent of America's primary energy and 75 percent of its electricity, which can jump to 80 percent when a majority of the population is at home using heating or cooling systems and the seasons reach their ...

Computer Sciences

New AI model tries to synthesize patient data like doctors do

Artificial intelligence will never replace a doctor. However, researchers at the Department of Energy's Pacific Northwest National Laboratory have taken a big step toward the day when AI can help physicians predict medical ...


The environmental cost of cryptocurrency mines

Bitcoin, Ethereum, Litecoin and Monero—the names of digital-based cryptocurrencies are being heard more and more frequently. But despite having no physical representation, could these new methods of exchange actually be ...

Energy & Green Tech

New exploration method for geothermal energy

Where to drill? This is the basic question in the exploration of underground energy resources, such as geothermal energy. Water in rocks flows along permeable pathways, which are the main target for geothermal drilling. Borehole, ...

Energy & Green Tech

Using mountains for long-term energy storage

Batteries are rapidly becoming less expensive and might soon offer a cheap, short-term solution to store energy for daily energy needs. However, the long-term storage capabilities of batteries, for example, in a yearly cycle, ...

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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