teacher’s notes
student’s notes
Dangerous Earth: a
plate tectonic story
Ideas and Evidence in Science – a comprehension
activity on plate tectonics
Learning objectives:
•
several of the Earth’s tectonic plates move at
about the same speed as fingernails grow –
around 35 mm / yr
•
plates are made of lithosphere (crust plus
the upper part of the mantle)
•
beneath the lithosphere is the
asthenosphere, part of the upper mantle that is
ductile because it contains 1-10% molten
material as films around the crystals
•
the Earth’s magnetic field has ‘flipped’ (the N
pole becoming the S pole, and vice versa) many
times over geological time
•
rocks magnetised in the direction of today’s
magnetic field have normal magnetism, rocks
magnetised when the field was the other way
round have reversed magnetism
•
as tectonic plates move apart, new rock is
formed and this ‘locks in’ the direction of the
magnetic field at the time
•
reading and written communication skills
Timing: 30 minutes
Pupils are to read and answer questions on the
student's material text.