Tests Taken: 3800
Published on: 07 Mar 2019
You should spend about 20 minutes on this task.
The diagram shows the production of hydroelectricity
Summarise the information by selecting and reporting the main features, and make comparisons where relevant.
You should write at least 150 words.
You should spend about 40 minutes on this task.
Missions to explore space are hugely expensive, and there are problems on Earth which demand attention. The number of these missions needs to be reduced.
Do you agree or disagree?
Give reasons for your answer, and include any relevant examples from your own knowledge or experience.
You should write at least 250 words.
Here is a summary of the process by which hydroelectric power is produced.
In general, the system utilises the weight of water held at higher elevations, whereby the Earth's gravity sees this liquid migrate downwards through subterranean" pipework, in the process having its potential energy 'cleanly' converted to a transmittable electrical form via a generator anchored sturdily at mid-point in the construction.
Looking in detail, the process begins with a large stable reservoir created by a sloping, cemented, and suitably reinforced wall. Driven by the considerable pressure at the lower depths, water is forced through a long and cryptically’" named ‘penstock chamber— although the fluid must first pass through a succession of grates to exclude solid particles, the larger of which could obviously be catastrophic for the turbine blades which follow.
As for the electricity production itself, the water passes through the turbine cavity, thereby revolving its wheel, thick cylindrical axle, and the generating apparatus directly coupled above within the appropriately named ‘powerhouse’. The resultant electrical current travels via three cables to a nearby transformer, where it is stepped up to a higher voltage suitable for longdistance; transmission, whilst the water, gushing from the: dam's base, forms a river flowing onwards.
Recently, China has launched another spacecraft, and announced intentions of ultimately establishing a space station — yet this is a country facing mammoth problems of underdevelopment and pollution. This inevitably raises the issue regarding where financial priorities should lie, yet I hold the view that exploratory space missions are certainly worthwhile, and should be continued.
Such voyages help provide an awareness of extraterrestrial threats to this very planet. That celestial firmament, seemingly so innocuous, actually contains innumerable rogue bodies, some with eccentric orbits which intersect Earth’s. Thus, collisions inevitably occur — for example, scientists now believe such a strike witnessed the demise of the dinosaurs, and for those who claim this risk is statistically negligible, the 1908 Tunguska event can be cited. Although little known (since this object fortuitously exploded in the remote Siberian tundra), it illustrates consequences which could truly be apocalyptic in scale. The point is, by gaining conversancy with space, astronomers can obtain crucial forewarning of such potential disasters.
Apart from this safety aspect, space missions provide fruitful stimulation to human imagination. Space is undeniably a beautiful, majestic, and mysterious frontier, its limitless realms essentially unexplored. With so many dedicated individuals, both professional and amateur, drawn to this field, missions there will focus increasing attention on what is clearly an altruistic and noble goal. Such endeavours can only be positive for a society adrift, struggling to find meaning and purpose.
The point could be made that Earth’s problems, particularly of the environment, demand priority. However, it is precisely through gaining a platform in space that humanity can deal with these. Observations from these heights allow detailed monitoring of the planet, its biosphere, and measurelessly complex meteorological effects, and only with an ongoing stream of such accurate space-sourced information can the alleviation of problems such as global warming, poverty, and pollution be achieved.
My conclusion is that the advance into space must not cease.
To conclude, by providing security and challenging our minds, our quest into the heavens must continue. This road only offers enticing prospects of insight, wonder, and discovery.