Robotics

Can a robot operate effectively underwater?

If you've ever watched Planet Earth, you know the ocean is a wild place to live. The water is teeming with different ecosystems and organisms varying in complexity from an erudite octopus to a sea star. Unexpectedly, it is ...

Engineering

Agile underwater glider could quietly survey the seas

Autonomous underwater vehicles have become versatile tools for exploring the seas. But they can be disruptive to the environment or have trouble traveling through confined spaces.

Energy & Green Tech

Fukushima nuclear plant operator: Seismometers were broken

The operator of the wrecked Fukushima nuclear power plant said Monday that two seismometers at one of its three melted reactors have been out of order since last year and did not collect data when a powerful earthquake struck ...

Energy & Green Tech

Tunnels to become carbon-neutral energy suppliers

After completion in about ten years, the Brenner base tunnel is expected to provide relief for transit traffic between Italy and Austria. The Brenner Base Tunnel Company (BBT SE) and Innsbrucker Kommunalbetriebe (Innsbruck ...

Engineering

Attachable skin monitors that wick the sweat away

A new preparation technique fabricates thin, silicone-based patches that rapidly wick water away from the skin. The technique could reduce the redness and itching caused by wearable biosensors that trap sweat beneath them. ...

Energy & Green Tech

Water leaks indicate new damage at Fukushima nuclear plant

Cooling water levels have fallen in two reactors at the wrecked Fukushima nuclear plant since a powerful earthquake hit the area last weekend, indicating possible additional damage, its operator said Friday.

Security

Massive breach fuels calls for US action on cybersecurity

Jolted by a sweeping hack that may have revealed government and corporate secrets to Russia, U.S. officials are scrambling to reinforce the nation's cyber defenses and recognizing that an agency created two years ago to protect ...

page 1 from 22

Water

Water is a ubiquitous chemical substance, composed of hydrogen and oxygen, that is essential for the survival of many known forms of life. In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam. Water covers 71% of the Earth's surface. On Earth, it is found mostly in oceans and other large water bodies, with 1.6% of water below ground in aquifers and 0.001% in the air as vapor, clouds (formed of solid and liquid water particles suspended in air), and precipitation. Saltwater oceans hold 97% of surface water, glaciers and polar ice caps 2.4%, and other land surface water such as rivers, lakes and ponds 0.6%. A very small amount of the Earth's water is contained within biological bodies and manufactured products. Other water is trapped in ice caps, glaciers, aquifers, or in lakes, sometimes providing fresh water for life on land.

Water moves continually through a cycle of evaporation or transpiration (evapotranspiration), precipitation, and runoff, usually reaching the sea. Winds carry water vapor over land at the same rate as runoff into the sea. Over land, evaporation and transpiration contribute to the precipitation over land.

Clean, fresh drinking water is essential to human and other lifeforms. Access to safe drinking water has improved steadily and substantially over the last decades in almost every part of the world. There is a clear correlation between access to safe water and GDP per capita. However, some observers have estimated that by 2025 more than half of the world population will be facing water-based vulnerability. Water plays an important role in the world economy, as it functions as a solvent for a wide variety of chemical substances and facilitates industrial cooling and transportation. Approximately 70 percent of freshwater is consumed by agriculture.

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