◄Back

# Long description

Figure 1 A cross section through the surface of the Earth. On the left hand side there are mountains, which slope down to the right to lower land, and then about two-thirds of the way across the diagram, the coast. To the right of this is the ocean, which gradually deepens up to the right hand edge.

In the top right of the diagram is a picture of the sun. Below this, two arrows labelled 'evaporation' point vertically upwards from the surface of the ocean. Above these arrows it says 'water vapour', and above that is a picture of a cloud.

An arrow labelled 'wind' points to the left from the cloud to another cloud. Another arrow, this time labelled 'cloud rising' points to the left and a little up to a third cloud. Rain is falling from this cloud into a lake at the edge of the mountainous area. From the lake, a river meanders its way past a town to the ocean.

From the third cloud, another arrow points up and to the left to a final cloud. From this cloud snow is falling onto the tops of the mountains.

Small blue arrows point vertically down from the surface of the land into the ground. The bottom part of the cross section through the surface is shaded a darker colour than the rest. On the left hand side the boundary between the light and dark areas is about half way between the bottom of the diagram and the peak of the mountain. The boundary slopes gently down to the right, while the light coloured area on top gradually becomes thinner, so that at the coast the lighter coloured area vanishes, and the entire area beneath the ocean is the darker colour.