BBC Learning Zone Clips

CLIP 13428

If the whole world jumped at the same time would the planet move?

If the whole world jumped at the same time would the planet move?
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Key Info
  • If the whole world jumped at the same time would the planet move?
  • Duration: 3:59
  • Presenter 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 2ms per day. To produce his data he asks 50,000 people at the Reading festival to all 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, i.e. 6.9b people 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. QED the myth is false. First broadcast on BBC Learning Zone and BBC3 in March 2012 as part of the series The Secrets of Everything.
  • Subject:

    Science

       Topic:

    Phys: Forces - Contact and Non-contact

  • Keywords: Earthquake, angular momentum, spin, seismologist, Richter scale, day length, TheSecretsofEverything
Ideas for use in class
  • Students can 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. Cross curricular links with Geography and Geology concerning earthquakes. Links with astronomy and how angular momentum is conserved in spinning neutron stars and black holes. Contains examples of ‘How Science Works’.
Background details
  • Clip language : English
  • Aspect ratio : 16x9

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