Articles on this website range from being very general to being relatively scientific. To help you out, each article has been given one of four content ratings: Beginner, General, Informed, or Advanced. Each has an associated symbol (shown below) which will be displayed at the start of each article. Furthermore you can browse our archives by content rating using the links on the left menu.

This article is rated Beginner, it is a good introduction to the topic.
This article is rated General, no prior knowledge or experience is assumed.
This article is rated Informed, familiarity with the subject matter is assumed.
This article is rated Advanced, it may contain jargon or scientific content.

Please note that these ratings are merely rough guides and that most content on the site should be appropriate for all readers. For example, Beginner articles are often of interest to even very informed people because they put a new spin on old concepts. Likewise, advanced articles – while being more scientific, should not be too much of a stretch for most readers to engage with.