Methodology of teaching informatics

The Sir Darya River

The name, which comes from Persian and has long been used in the East, is a relatively recent one in western writings; prior to the early 20th century, the river was known by various versions of its ancient Greek name. Following the Battle of Jaxartes the river marked the northernmost limit of Alexander the Great's conquests. Greek historians have claimed that here in 329 BC he founded the city Alexandria Eschate (literally, "Alexandria the Furthest") as a permanent garrison. The city is now known as Khujand. In reality, he had just renamed (and possibly, expanded) the city of Cyropolis founded by king Cyrus the Great of Persia, more than two centuries earlier.
The river rises in two headstreams in the Tian Shan Mountains in Kyrgyzstan and eastern Uzbekistan—the Naryn River and the Kara Darya—and flows for some 2,212 kilometres (1,374 mi) west and north-west Uzbekistan and southern Kazakhstan to the remains of the Aral Sea. The Syr Darya drains an area of over 800,000 square kilometres (310,000 sq mi), but no more than 200,000 square kilometres (77,000 sq mi) actually contribute significant flow to the river. Its annual flow is a very modest 37 cubic kilometres (30,000,000 acre ft) per year—half that of its sister river, the Amu Darya.
Along its course, the Syr Darya irrigates the most fertile cotton-growing region in the whole of Central Asia, together with the towns of Kokand, Khujand, Kyzylorda and Turkestan.
An extensive system of canals, many built in the 18th century by the Uzbek Khanate of Kokand, spans the regions the river flows through. Massive expansion of irrigation canals during the Soviet period, to irrigate cotton fields, caused ecological damage to the area, with the river drying up long before reaching the Aral Sea which, as a result, has shrunk to a small remnant of its former size. With millions of people now settled in these cotton areas, it is not clear how the situation can be rectified.

The Zarafshan River

Zeravshan River is a river in Central Asia. Its name, "sprayer of gold" in Persian, refers to the presence of gold-bearing sands in the upper reaches of the river. To the ancient Greeks it was known as the 'Polytimetus'. It was also formerly known as Sughd River.
It rises at 39°30′N 70°35′E / 39.5°N 70.583°E / 39.5; 70.583 on the fringes of the Pamirs in Tajikistan, flowing due west for some 300 kilometres (190 mi), passing Penjikent before entering Uzbekistan at 39°32′N 67°27′E / 39.533°N 67.45°E / 39.533; 67.45, where it turns west-to-north-west, flowing past the legendary city of Samarkand, which is entirely dependent on the oasis thus created, until it bends left again to the west north of Navoiy and further to the south-west, passing Bukhara before it is lost in the desert beyond the city of Qorako‘l (Karakul), not quite reaching the Amu Darya, of which it was formerly a tributary.