You can reverse continental drift!
Back in the time of the dinosaurs, Australia was just one small part of a much bigger continent. Can you piece together the ancient supercontinent, Gondwana?
You will need
- Scissors
- A copy of the print-out
What to do
Roughly cut out the different continents. Don’t worry about following the coast exactly.
Arrange them like a world map. Going left to right, first put South America, then Africa, India and finally Australia.
Underneath them all, put the last continent, Antarctica.
We’re going to reverse continental drift. Slowly move each continent down, towards Antarctica. Do you notice any of the coastlines matching up?
Eventually, the continents will join up into one blob. Don’t worry if there are a few gaps here and there – the shape of the continents has changed a bit over the past 100 million years. Congratulations! You’ve recreated the super continent known as Gondwana.
What’s happening?
The ground under your feet might feel pretty stable, but it’s actually moving. The rocks beneath your feet float on a sea of molten magma (lava). When the magma moves, it drags the surface rocks along for the ride. This is known as continental drift.
We haven’t always known about this. Continental drift was a controversial theory for many years. Many scientists could not imagine a force strong enough to shift entire continents. But there was a lot of evidence. For example, the coastlines of South American and Africa match surprisingly well, and similar fossils are found in matching regions on the continents.
Eventually, scientists set up experiments to measure the speed of the continents. One way is to measure the distance from Earth to the Moon, by bouncing lasers off the Moon’s surface. Astronauts set up mirrored reflectors on the Moon just so we could do this!
Current measurements show that Australia is the fastest continent, moving north at about 7 centimetres per year. That adds up to 70 kilometres every million years, or a whopping 7,000 kilometres since the breakup of Gondwana, 100 million years ago.
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