Recording a lecture with my macbook air?

[Murl]

I am in Dental school and we just started a class that doesn't use tegrity, which records audio and captures the computer screen all at the same time so you see the slides with the audio. I want to record the lectures in a lecture hall that seats 120 people. The lecture material is in ppt form. I have garage band, audacity and MS Word 2011 (has the not feature that records audio). I don't take an overwhelming amount of notes and I usually add them to the notes in ppt if I do. We do have permission to record the lectures so that is not an issue. What app should I use for this and should I use the built in mic or an external?

Any advice is appreciated.

 

[zimv20]

do a search, this has been covered before. short answer: you won't be happy with the audio using a laptop like that.