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 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.
Teacher Notes
This short film could be used as an introduction to the composition of the atmosphere.
This could be extended with practical work on the proportion of oxygen in the atmosphere and research into the other components of the atmosphere.
Curriculum Notes
These short films will be relevant for teaching physics and chemistry at both KS3 and KS4 in England, Wales and Northern Ireland and National 4/5 in Scotland.
More from the Secrets of Everything:
Can you make a star on Earth? video
Greg Foot demonstrates that a star is just like a continuous chemical reaction.
How big is one giant leap on the Moon? video
Greg Foot finds out how high he can jump on Earth compared to on the surface of the Moon.
How can you survive a lightning strike? video
Just how dangerous is lightning and how can anyone survive a direct lightning strike?
If the whole world jumped at the same time would the planet move? video
Greg Foot investigates the question on everyone's lips; what if everyone in the world jumped at the same time?
Could I survive an asteroid strike? video
Greg Foot investigates what would happen if an asteroid collided with Earth.
Why can't I run fast? video
Will humans be able to run faster and continue to break world records?
Why do boomerangs come back? video
Why a boomerang will always return to its thrower when thrown correctly.
Why is fire hot? video
Greg Foot demonstrates how fuel, heat and oxygen are required to produce fire.
Can I escape from quicksand? video
Why quick sand is dangerous and the forces involved that make it difficult to escape from.
