主播大秀

Presenter Greg Foot discovers why the sky is blue. He explains that outside the Earth鈥檚 atmosphere, space looks black but from the Earth鈥檚 surface the sky looks blue. He investigates this effect by launching a weather balloon. The helium filled balloon rises through the atmosphere reaching a height of twenty thousand metres, filming this effect as the colour changes from blue to black. The balloon also collects data concerning atmospheric pressure and temperature.

Greg then demonstrates that the graphs for sky colour and atmospheric pressure are a very close match. He finishes by explaining that the sunlight is scattered by the Earth鈥檚 atmosphere and that this effect increases as the atmosphere gets denser near the Earth鈥檚 surface. This makes the sky look blue.