100th ELI! Simulating the formation and growth of crystal lattices

Our hundredth ELI activity is 'Crystallisation in a pudding dish'. This is a teacher-led demonstration of the formation of regular patterns with spherical objects, akin to the way in which crystal lattices may be produced in nature. The regular pattern formed by the sweets represents the arrangement of atoms in a crystal. The longer the time available for the spheres to form such a lattice, the bigger and better formed the crystal will be, as shown by the quartz crystals and regular arrangement of the sweets in the photo above. The volcanic glass shown has no crystalline structure at all; the sweets have had no time to form a regular lattice. One of the great advantages of this activity is that you can eat the chocolates at the end!
This is one of several activities about crystallisation - see the related activities listed on our home page.

Readers' extension ideas added

The following suggestions have been added as extension ideas:-
A dinosaur in the yard - extension
Salt of the Earth - extension
What is the geological history? - extension
Dustbowl; investigating wind erosion - extension
We are very pleased to add your ideas to our activities. If you have further suggestions, please do contact us.

Well-travelled friends sending geological postcards

You have received two postcards from around the world. One friend has visited areas with spectacular sandstone scenery and the other has been to limestone landscapes. Can you work out which postcard is which and give reasons for your answers? Which landscape is shown on the postcard above? This is the latest ELI extension following Geological postcards 2.
Use our new ELI search engine to find related topics.

ELI Search facility and New ELI

Our latest activity is 'The unfair 'build your own crystal' race. It is unfair because some groups of pupils have more time to complete the task than others. This is a quick game which can be used as a lesson starter to show that the more time there is available to ‘build’ a crystal or model, the larger it will become.
You can find activities related to this on the new-look ELI home page.
We have also added a 'Search activities' facility to the site. This will make finding the Earth-related topic you want much easier.
As ever, we should appreciate your comments and suggestions - contact us.

How could you become fossilised?

This photo is of the 4th century Tollund Man. He was preserved in a peat bog in Denmark. Have you tried the Earth Learning Idea 'How could I become fossilised?'? The activity encourages pupils to think through the fossilisation process.What would happen to your body if you fell into a river or the sea and died? The story is quite gruesome at first. Did you know that 99.9% of dead creatures are eaten and broken up and never become fossilised? It soon becomes apparent that the environment in which something dies is crucial to its fossilisation potential. To be classified as a true fossil, the object must have been preserved for at least 10,000 years. Therefore Tollund Man is not a fossil but he can be used to illustrate the principles of the process.
There are lots of ELI activities about fossils - click here for a list.