News tagged with energy

Related topics: electricity , energy consumption , renewable energy , energy efficiency , fossil fuels

As kids age, snacking quality appears to decline

The average U.S. child snacks three times a day. Concerned about the role of snacking in obesity, a team of researchers set out to explore how eating frequency relates to energy intake and diet quality in ...

May 06, 2014
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Energy drinks linked to teen health risks

(Medical Xpress)—The uplifting effects of energy drinks are well advertised, but a new report finds consumption among teenagers may be linked with poor mental health and substance use.

Mar 06, 2014
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Caffeine common in US kids, youths; mainly soda

Nearly 3 out of 4 U.S. children and young adults consume at least some caffeine, mostly from soda, tea and coffee. The rate didn't budge much over a decade, although soda use declined and energy drinks became ...

Feb 10, 2014
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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