Finding geographic coordinates
When Earth spins on its axis two opposite points stay in place – the North and South Poles. The great circle around Earth’s middle, equally far from the poles, is the equator (about 40 000 km long); it divides Earth into northern and southern hemispheres. Lines parallel to the equator are parallels (they get shorter toward the poles). Half-circles joining the poles are meridians; the one through the Greenwich observatory in London is the Prime (0°) meridian. Parallels and meridians form the graticule. Latitude is the arc in degrees from the equator to a point (0° to 90°; north or south). Longitude is the arc from the Prime meridian to the point (0° to 180°; east or west). Together latitude and longitude are the point’s geographic coordinates. Tashkent lies at about 41° N and 69° E. Along a meridian 1° is about 111 km.
Game “Coordinates”: draw a grid of 5 “parallels” and 5 “meridians” on the board or floor (labelled 0°, 10°, 20°…). Teams call out one “city” coordinate each time (for example 20° N, 30° E) and the opponent finds it on the grid. Then find Tashkent and other cities on a globe or map. Safety: clear the play area of obstacles; do not slip when chalking on the floor.