Greg Foot investigates the urban myth that if the whole population of the world jumped at the same time, it could cause an earthquake big enough to affect the speed at which the Earth turns on its axis.
He starts by looking at data which showed that a Japanese earthquake that measured 8.9 on the Richter scale caused the rotation of the Earth to speed up by 2 metres per day.
To produce his data he asks 50,000 people at Reading festival to jump at the same time. This causes an earthquake that measures 0.6 on the Richter scale.
Greg then calculates that if the whole population of the Earth jumped up and down at the same time, it would still be a factor of seven million short of altering the speed at which the Earth rotates.
Teacher Notes
Students could investigate the effect of the conservation of angular momentum by looking at clips of ice skaters spinning with arms held out and how spin increases when they draw their arms in.
There are clear cross-curricular links with geography and geology (earthquakes), and with astronomy on how angular momentum is conserved in spinning neutron stars and black holes.
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?
Could I survive an asteroid strike? video
Greg Foot investigates what would happen if an asteroid collided with Earth.
Why is the sky blue? video
Greg Foot discovers why the sky is blue by examining the effect of the atmosphere.
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.
