Maps and place knowledge

The easting

提示Go along the corridor before you go up the stairs.

为什么Eastings are the numbers that increase from left to right across the map; northings increase up it. A four-figure reference names one grid square, a kilometre across.

Six

提示Add one more digit to each half of a four-figure reference.

为什么A four-figure reference names a whole 1 km square. Adding an extra digit to each half splits that square into tenths, so the reference locates you to within 100 m.

1 kilometre

提示Work out what a single centimetre is worth first, then double it.

为什么A scale of 1:50 000 means 1 cm on paper stands for 50 000 cm on the ground, which is 500 m. Two centimetres is therefore 1000 m. Most OS Landranger maps use this scale.

steep

提示The lines are squeezed because you gain a lot of height over very little ground.

为什么Each contour joins points of equal height, so lines close together mean a big height change across a short distance. Widely spaced contours mean gentle, easy walking.

The Pacific Ocean

提示It sits between Asia and the Americas, and its name means peaceful.

为什么It covers about a third of the planet - wider than every landmass put together. The five oceans are the Pacific, Atlantic, Indian, Southern and Arctic.

0 degrees

提示It is the starting line from which every other parallel is counted north or south.

为什么Latitude is measured outwards from the Equator, so the poles sit at 90° north and 90° south. Longitude is measured the same way from the Prime Meridian at Greenwich.

Wales

提示The country immediately west of England, with Snowdonia in its north.

为什么The four capitals are London for England, Edinburgh for Scotland, Cardiff for Wales and Belfast for Northern Ireland. Cardiff stands on the Bristol Channel in the south.

The mantle

提示The thick, slowly creeping layer that carries the plates on its back.

为什么It is by far the thickest layer, made of hot rock that flows a few centimetres a year. Convection currents within it are what drag the plates about.

A constructive boundary

提示New rock rises to fill the gap, so land is being made rather than destroyed.

为什么At a constructive (divergent) boundary such as the Mid-Atlantic Ridge, magma rises into the gap and cools into fresh crust. Iceland is being widened by one right now.

The Sahara

提示Its name is simply the Arabic word for desert.

为什么It is the largest hot desert on Earth, roughly the size of the United States. South of it lies the dry grassland of the Sahel, and further south again the Congo rainforest.

The Himalayas

提示It holds Everest and separates the subcontinent from Tibet.

为什么The range was thrown up where the Indian plate crashed into Asia, and it is still rising. It blocks cold northern air and shapes the monsoon that waters India.

Russia

提示It spans eleven time zones, from the Baltic to the Pacific.

为什么It covers about an eighth of the world's land, though much of that is Siberian forest and tundra. Most of its people live in the European west, near Moscow and St Petersburg.