Water Definition

7/29/2019 Water Definition

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Read the text and write a title for it

Water takes many different shapes on earth: clouds in the sky, waves and icebergs in the sea,

glaciers in the mountain, aquifers in the ground, to name but a few. Through evaporation,

precipitation and runoff, water is continuously flowing from one form to another, in what is called

the great water cycle.

Because of the importance of precipitation to agriculture, and to mankind in general, we give

different names to its various forms : while rain is common in most countries, other phenomena

are quite surprising when seen for the first time: hail, snow, fog or dew for example. When

appropriately lit, rain takes many colours and forms a wonderful rainbow.

Similarly, water runoffs have played major roles in our history: rivers and irrigation brought the

water needed for agriculture and the seas offered opportunity for commerce. Less common forms

of runoffs are glacier and waterfalls. Through erosion, runoffs played also a major part in shapingour environment: valleys and river delta hosts many people.

Water also infiltrates the ground and goes into aquifers. This groundwater later flows back to the

surface in springs, or more spectacularly in hot springs and geysers. Groundwater is also extracted

artificially in wells.

Because water can contain many different substances, it can taste or smell very differently. In fact,

we have developed our senses to be able to evaluate the drinkability of water: we avoid the salty

seas and the putrid swamps, and we like the water that is adequate for our body.

Water has many unusual properties that are critical for life: it is a good solvent and has high

surface tension. Fresh water has its greatest density at 4°C: it becomes less dense as it freezes or

heats up. As a stable, polar molecule prevalent in the atmosphere, it plays an important

atmospheric role as an absorber of infrared radiation, crucial in the atmospheric greenhouse



effect. Water also has an unusually high specific heat, which plays many roles in regulating global

climate.

Water is a very good solvent and dissolves many types of substances, such as various salts and

sugar, and facilitates their chemical interaction, which aids complex metabolisms. Some

substances, however, do not mix well with water, including oils and other hydrophobic

substances. Cell membranes, composed of lipids and proteins, take advantage of this property to

carefully control interactions between their contents and external chemicals. This is facilitated

somewhat by the surface tension of water.

Water drops are stable due to the high surface tension of water. This can be seen when small

quantities of water are put onto a nonsoluble surface such as glass: the water stays together as

drops. This property plays a key role in plant transpiration.

A simple but environmentally important and unique property of water is that its common solid

form, ice, floats on the liquid. This solid phase, is less dense than liquid water, due to the geometry

of the strong hydrogen bonds which are formed only at lower temperatures. For almost all other

substances and for all other 11 uncommon phases of water ice except ice-XI, the solid form is

more dense than the liquid form. Fresh water is most dense at 4°C, and will sink by convection as

it cools to that temperature, and if it becomes colder it will rise instead. This reversal will cause

deep water to remain warmer than shallower freezing water, so that ice in a body of water will

form first at the surface and progress downward, while the majority of the water underneath will

hold a constant 4°C. This effectively insulates a lake floor from the cold.

Life on earth has evolved with and fine tuned itself to the important features of water. The

existence of abundant liquid, vapor and solid forms of water on Earth has no doubt been an

important factor in the abundant colonization of Earth's various environments by life-forms

adapted to those varying and often extreme conditions.

Taken and adapted from: http://www.wordiq.com/definition/Water

http://www.wordiq.com/definition/Water

http://www.wordiq.com/definition/Water



Read the text and give it a title.

One of the most popular questions asked when purchasing a new computer is "Should I buy a

Laptop or Desktop computer?" A person must consider all the advantages and disadvantages of

both platforms, and decide which one fits their needs the most.

The Personal Computer industry was first created with the desktop computer. There are many

different definitions and variations of the desktop computer, but it is most commonly thought of

as the Tower (or CPU, as some might say) that is separate from the display. Desktops have been

the dominant form factor for PC's since the beginning, and even in its current form is still very

similar to the original design.

Laptops originally were released in the mid 1980's, but did not become mainstream until the early

1990's. The goal of a laptop was to fuse a computer system together with a display and device,

and make it so that it could be carried with a person. While the first laptops were a bit awkward,

they fast became sleek and very useful machines.

Desktop computers have always been at the forefront of new technology; most every new

technology for computers is released on a desktop system first. Laptops are considered the

desktop's younger brother; while having the ability to take the computer with you is convenient, it

comes at the cost of slower performance, decreased usability, and shorter "on-time" required by

using a battery.

In today's world, some of these nuisances are still to be found, but are less pronounced. While

laptops are still the younger brother of desktops, they are no longer far from the tip of high

performance; laptops are now available that can rival even the beefiest desktop. And usability?

While the laptop is limited to a track pad or finger pointer, you can plug in a regular keyboard and

mouse (or any other input device) and use the laptop just like a desktop. And while batteries are

always getting better, just having a laptop will always include the handicap of being limited in "on-

time."

Laptops are the most convenient computers to use; you can do whatever you want, whenever you

want, wherever you want. While the hardware may not be the same, the software that you use on

a desktop or laptop will be identical; any software will run the same on a laptop or desktop.

In recent years, laptops have caught up on the technology curve. You can do just about anything

on a laptop that you can do on a desktop: write papers, browse the internet, edit pictures of video,

even watch a DVD. All this capability comes in a package that looks and feels just like another

textbook that easily fits in a bookbag or briefcase.



The main advantages to buying a laptop are that they have the ability to go anywhere and are

more convenient to use. They can also run all of the software a desktop can run; there is no

discernable difference.

Desktops have been the cornerstone of the Personal Computer market since the beginning. A

typical desktop looks like a rectangular box, being about 2-3 feet high, 1 foot wide, and about 3

feet deep. A desktop computer is not something one would usually move around; once it is in a

convenient place, such as underneath a desktop or on the floor, it will typically stay there for its

useful lifetime. The desktop is where everything takes place; it is what processes all the

information, takes in all of your inputs, and creates all of the outputs. While it is self-sufficient, it

does need a display device to allow the user to see what they are doing.

Desktops are always at the front of the technology curve. This is where the desktop shines: if

something brand new comes out, you can buy a desktop that will have it. Desktops are also the

best at the low-end; they can be the cheapest computer you can buy, and still have a lot of power

(what some call "bang-for-your-buck"). Desktops also do not rely on battery power to function; all

you do is plug it into a wall plug, and you can use it with no limitations of time.

The main advantages to buying a desktop are that they are the fastest Personal Computer

available, can be the cheapest available, and have the most expansion capabilities.

When buying a new computer, choosing between a laptop and a desktop can be a hard decision.

Keep this in mind: the desktop and laptop will run the same exact software; so the decision

becomes an argument of performance vs portability. Do you want run the latest and greatest

games and get your picture or video editing done in a snap? Or would you rather sit on your

couch, read email, and browse the internet while watching TV?

This decision comes down to personal preference. If you are looking for a good computer that you

can take with you, a laptop is a good choice for anyone who does not need the absolute "top of

the line" computer available. Alternatively, a desktop is the better choice for someone who is

either looking to buy the cheapest available, or is looking to buy the best of the best on the

market.Taken and adapted from: http://techzone.illinoisstate.edu/guide/laptop_vs_desktop.shtml

http://techzone.illinoisstate.edu/guide/laptop_vs_desktop.shtml




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Water Definition