We don't have a real sense of height. Almost all of us can run nine kilometres on flat ground, but hardly anyone can climb Mount Everest, which is almost nine kilometres high. And the altitude at which humans can live permanently is probably only slightly above five thousand metres; the highest permanently inhabited settlement is La Rinconada in Peru. But this requires a high degree of adaptation on the part of humans.

In aviation, additional oxygen must be breathed at altitudes above three thousand metres, but the altitude at which oxygen deficiency begins to occur is much lower, depending on individual predisposition and previous prolonged exposure, and can occur as low as fifteen hundred metres.

But in order to properly assess the atmosphere, it is important that we also develop a sense of it.

How do you represent the relationship between the Earth's radius and the height of the atmosphere? In most representations, the atmosphere is shown as much too high.

But why? Quite simply because the atmosphere is just a thin layer surrounding the Earth. This becomes clear when you look at the figures:

Earth's radius: 6371 km

Height of the atmosphere above the Earth's surface: This is somewhat a matter of definition. Here, 11 km was chosen, a height below which three-quarters of the mass of the atmosphere lies and the air pressure is only a quarter of the air pressure at sea level.

If we now choose a scale where 1 km corresponds to 1 mm, the distance from the centre of the Earth to the Earth's surface would be 6371 mm. And the distance from the Earth's surface to the summit of Mount Everest would be 8.85 mm. These ratios cannot be reasonably represented on an even smaller scale, such as would be required for illustration in a book. As shown in the drawing below.

One way to represent the relationship is to use a tape measure outdoors or in a sufficiently large room. The task can then be to position a sheet of paper where the Earth's surface is and draw in various heights and depths.

• Mount Everest
• Mariana Trench
• Deepest hole on Earth
• Tallest building on Earth
• Tallest mountain in your own country, tallest mountains in neighbouring countries
• What was the highest point on Earth you have ever been to?
• What was the highest altitude you have ever reached? For example, in an aeroplane.

Does not fit on the sheet of paper:

• Altitude of the ISS
• Geostationary orbit, for example for television satellites.

• Tape measure. Paper tape measures, such as those available in DIY stores and furniture stores, can also be stuck together.
• Pen