Monthly Archives: May 2014

Get ready for Chapter 5!

today at 12:00 p.m. (noon in Berlin) Chapter 5 of our course will be activated.

We hope, you are all doing well!

After the halftime break, we will practise the handling with the International Tables a little further. But in contrast to staring only at circles and commas we will additionally look at real world crystals and some of their symmetry and physical properties. And you can be curious about the story of one of the most thrilling scientific discoveries of the last century: the discovery of quasicrystals by Dan Shechtman.

Maybe some of you are also willing to contribute to the growing list of one concrete example of a crystal for each of the 230 space groups? Have a look at:

https://iversity.org/my/courses/the-fascination-of-crystals-and-symmetry/discussions/43529

Looking forward to meet you at class and in the forum!

Michael and Frank

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Chapter 4 about to start!

this has been great fun so far!

We like that you are asking so many questions on the forum and we enjoy all the photos you are uploading to our flickr page, for example the wonderful Escher-like tessellations by Daniel Wyllie:

https://www.flickr.com/photos/100542173@N05/14107072376/

Your fellow student @chemraven has some interesting posts about the symmetry of molecules on his blog:

http://chemdiary.blogspot.de/search/label/symmetry

Today, we will release Chapter 4 of our course.

We will focus on symmetry elements that separate crystal structures from macroscopic objects: glide planes and screw axes. For illustration purposes, the colorful locomotives appear again in some animations.

After that we are ready to climb up the the last step of our “ladder of crystal classification”, reaching, finally, the space groups. We will open the “crystallographers’ bible” and will explain what “psalms” are important to crystallographers.

After this week, we will take a short break. Some of you can catch up with the rest of the course. Others may want to review what they have learned so far. In the week after that we will take a close look at actual crystal structures. If you want to prepare yourself, you may already download and install the CCDC software “Mercury” on your computer. You can find it here:

http://www.ccdc.cam.ac.uk/Solutions/FreeSoftware/Pages/FreeMercury.aspx

Michael and Frank

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PS:

You may also join our Crystal MOOC facebook page at:
https://www.facebook.com/crystalmooc

If you like, you can also share your location with your classmates, in order, for instance, to arrange local meet-ups:
https://www.zeemaps.com/map?group=780180

Get Ready for Chapter 3!

first of all, let us thank you for your participation in this MOOC. We also really enjoy seeing the pictures you are uploading to our flickr page:

https://www.flickr.com/photos/100542173@N05/

You may also join our Crystal MOOC facebook page at:
https://www.facebook.com/crystalmooc

And we are doing our best to answer all your questions that come up in the forum. We really appreciate your input and encourage you to discuss the content of the course with your peers.

The upcoming chapter is all about symmetry. We will start with the symmetries that can be found in everyday objects. For example, you will investigate the symmetry elements of the queen of clubs or a boomerang.

You will then learn how to classify crystals into their respective classes. We have prepared a small poster, so you can keep track of your very own collection of crystals.

Finally, we want to begin to talk about translational symmetry. This symmetry is a particular feature of crystal structures with their repetitive patterns. However, we will go easy with you and explain it with an imaginary walk on a beach and look at drawings of the famous artist M.C. Escher.

We hope that you are curious, how our crystallographic journey continues.

See you in class (at 12:00 CEST)!

Michael & Frank

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