Hardware

Hardware is a general term that refers to the physical artifacts of a technology. It may also mean the physical components of a computer system.

Hardware historically meant the metal parts and fittings that were used to make wooden products stronger, more functional, longer lasting and easier to fabricate or assemble. In modern usage it includes equipment such as keys, locks, hinges, latches, corners, handles, wire, chains, plumbing supplies, tools, utensils, cutlery and machine parts, especially when they are made of metal. In the United States, this type of hardware has been traditionally sold in hardware stores, a term also used to a lesser extent in the UK.

In the electronics and especially computer industries, computer hardware specifically means the physical or tangible parts of the equipment, such as circuit boards, keyboards, monitors etc., in contrast to non-physical software running on the computer or other device.

In a more colloquial sense, hardware can refer to major items of military equipment, such as tanks, aircraft or ships.

River

A river is a natural waterway that transits water through a setting from higher to lower elevations. A river may have its basis in a spring, lake, from damp, boggy landscapes where the soil is waterlogged, from glacial melt, or from surface runoff of precipitation. Almost each and every one river is joined by other rivers and streams termed tributaries the highest of which are known as headwaters. Water may also begin from groundwater sources. Throughout the course of the river, the total volume transported downstream will often be a combination of the free water flow together with a important contribution flowing through sub-surface rocks and gravels that underlie the river and its floodplain. For many rivers in large valleys, this unseen component of flow may greatly go above the visible flow.

From their source, all rivers flow downhill, typically terminating in the sea or in a lake, through a confluence. In arid areas rivers sometimes end by losing water to desertion. River water may also infiltrate into the soil or pervious rock, where it becomes groundwater. Excessive abstraction of water for use in commerce, irrigation, etc., can also cause a river to dry before success its natural terminus.

Historical perspective

Based on the available evidence, scientists have reconstructed detailed information about the planet's past. Earth is estimated to have formed approximately 4.55 billion years ago out of the solar nebula, along with the Sun and other planets. The moon formed relatively soon afterwards.

Initially molten, the outer layer of the planet cooled, resulting in the solid crust. Outgas sing and volcanic activity produced the primordial atmosphere. Condensing water vapor, augmented by ice delivered by comets, produced the oceans. The highly energetic chemistry is believed to have produced a self-replicating molecule around 4 billion years ago.

Continents formed, then broke up and re-formed as the surface of Earth reshaped itself over the course of hundreds of millions of years, occasionally combining to make a super continent. Roughly 750 million years ago, the earliest known super continent Rodinia, began to break apart. The continents later recombined to form Pannotia which broke apart about 540 million years ago, then finally Pangaea, which broke apart about 180 million years ago.