Monday 31 August 2015

What drives the plates?

The new ELI today is 'What drives the plates? - using a pupil model to demonstrate that slab pull is the main plate-driving force'

Recent evidence has shown that the traditional view of mantle convection being the main driving force in lithospheric plate movement is probably incorrect. If it were the main driving force, then plates with the largest surface area would move fastest because they would have the largest area on which the mantle convection forces would act – this is not the case. However, those plates that have the longest subducting margins, with geophysical evidence of the deepest subduction slabs, do seem to be moving fastest – which is why this is now considered to be the main driving force. A fourth force that might be important is subduction suction where the old, cold oceanic plate subduction trench migrates towards the oceanic ridge pulling the over-riding plate behind it. Some geophysicists argue that this is an important driver of plate movement.
There are many plate tectonic ELIs on our website.

Monday 24 August 2015

‘Tagging’ water molecules – to explore the water cycle

Have you tried this thought experiment to investigate the water cycle? "‘Tagging’ water molecules – to explore the water cycle" is one of a series of ELIs about the water cycle.

Pupils carry out a thought experiment to visualise the movement of an imaginary ‘tagged’ bright blue water molecule as it moves through various parts of the water cycle. Molecules can actually be ‘tagged’ and traced using radioactive isotopes, so the principle is used – if not the bright blue colour.
There are five Earthlearningidea Water Cycle activities and they demonstrate pupils' progression of thinking skills. They can be found in the index on the website under 'Water cycle'.

Monday 17 August 2015

Evidence for continental drift

'Did the continents move for you?' In this ELI+ activity, pupils plot the movement of continents using apparent polar wandering curves.

By doing this Earthlearningidea pupils can:-
- appreciate that magnetic minerals become magnetised in the direction of the Earth’s magnetic field;
- by recording this remanent magnetisation, it is possible to construct apparent polar wandering curves for each continent;
- realise that the magnetic pole has not wandered but the apparent curve can be used to determine the position of the continents at the time of the formation of the rocks with the magnetic minerals;
- the apparent polar wandering curves give good evidence for continental drift.
Other related activities can be found on the website.

Monday 10 August 2015

Fossilise! A game about fossils

A rainy day in the holidays? Try 'Fossilise!' This ELI is a game about how fossils form and survive. You collect cards as you play the game and, of course, everyone wants to win to collect the Gold Nugget card.

You will need copies of the game and the cards, some scissors to cut out the cards and counters, dice and shakers.
More activities for children to try at home can be found on our website, although they will need adult supervision as they are designed primarily for use in schools.

Monday 3 August 2015

Karstic scenery - modelling chemical weathering

The new ELI published today is 'Karstic scenery - in 60 seconds: modelling the chemical weathering of limestone'.

 In this activity pupils compare the results of water on sugar cubes with features which develop as a result of the chemical weathering of limestone.
Many more activities about weathering can be seen on the home page of our website under 'Activities related to the new ELI'.

Saturday 1 August 2015