Do many phd students do demonstrating in lab classes, or take tutorials? How much can one expect to get paid? Does it interupt with the research? Is is worth it? (So many questions...)

Demonstrating above everything else, probably puts you in good stead if you want to go on to become a lecturer. I regard it as training myself. It shouldn't cut into your time doing your research work, and hence you would probably only have the opportunity to work for an hour or two a week anyway.

There are usually many more PhD students than there are opportunities to demonstrate or take tutorials. Most people end up doing only a few hours every term. It can be really good experience and will be of some help in deciding whether you want to continue in academia. The money is usually pretty good and will be tax free for full time PhD students. Rates vary but through an extensive survey of a single PhD student we heard that he got £13.50/hour for demonstrating.

At my university we get paid £30 per hour!

Which university is that?

If a PhD studentship is advertised as a teaching studentship does that mean that any teaching done will be included as part of the studentship or will it be paid in excess separate to studentship? Thanks.

In my London University we get £10 an hour for demonstrating and £18 an hour for tutorials. It is worth emailing your departmental secratery to keep you in mind if any teaching oppertunities arise.

Teaching studentships are usually positions which are funded internally by the university. Although there may be opportunities to earn money by taking on work beyond the stated hours, in most cases you will not be paid extra for any of the teaching which is conditional for your studentship.