Getting the depth right

A question that often comes up in face to face workshops is a really good one that is also difficult to answer! The question is usually ‘what depth do I need to go into?’ and it will be with regards to one of the new areas of the course. My initial feeling was to relate the syllabus statement to the learning objectives. For example, in topic 11.3 (measurement and data processing – spectroscopic identification of organic compounds) we see that under ...

Oxygen

Dione - not something that you would probably hear about in everyday conversations bu tin the next few years this name may become one of the most important words in our language. Why? Well first of all, what is Dione? It is, in fact, one of Saturn's many moons. Image kindly reproduced according to the licence at: http://en.wikipedia.org/wiki/File:Dione3_cassini_big.jpg Why has it been thrust into the limelight? Well, it is thought that it has a thin layer of molecular oxygen around the moon. So what is ...

Superionic Water

  New Scientist magazine, 4th September 2010 Water is now thought to exist in a really exotic form in the centre of Uranus and Neptune. Image reproduced according to the licence at: http://en.wikipedia.org/wiki/File:Neptune.jpg Extremely high temperatures and high pressures mean that the water may behave like a solid and a liquid at the same time. The extreme conditions would mean that the water becomes ionised - oxygen ions would form a crystal like lattice that would allow hydrogen ions to flow through it. And the ...

Working out climate change using oxygen isotopes

  We are told that in the past the planet's atmosphere has been colder and warmer than it is today but how do scientists actually know this?   A variety of methods are used but one uses some straight forward (to understand - not necessarily carry out) chemistry. Oxygen has two stable isotopes, 16O and 18O. 16O evaporates faster than 18O so seawater will contain more 18O than 16O due to evaporation. The water will eventually make its way into rivers and back into the ...

Iron (Fe)

  Iron is essential to all living things but in large quantities can be toxic - possibly leading to liver and kidney damage.   However, we need Iron for our blood - to form haemaglobin and carry oxygen. Males need 7mg daily and females 11mg but only 25% of what is in food is actually absorbed. It is estimated that 500 million people are anaemic through lack of Iron. Click here to see more: http://www.periodicvideos.com/videos/026.htm It is also the heaviest element that can be made ...

Fuel Cells

Fuel cells a type of electrochemical cell. They work on the idea that one day they could replace the inefficient conversion of fuels to heat (approx 40%)  and then electricity with a more efficient (approx 80 - 85%) and cleaner way of producing electricity. Water is produced as a 'waste' product.   They are different electrochemical cells to the ones you will have studied at IB as they are open systems - fuel (in the form of Hydrogen and Oxygen) must be ...