Lecturing is one of the most common forms of teaching - in many degree programmes, tuition consists almost entirely of lectures supplemented by tutorials. To help students learn effectively in this context you should be aware of two common dangers:
a) Lectures can overload students with information. It is said that 20 minutes is about the longest a normal adult can concentrate uninterruptedly on a single task, so in a standard 50 minute lecture it is inevitable that students will lose concentration at times.
One classic study found that at the end of a typical undergraduate lecture packed with factual information, students could recall only about 20% of what they were told. Tested again a week later, they recalled only 10%. The study also found that students who took notes remembered less, presumably because the task of writing distracted them.
b) Lectures can encourage surface learning. Sitting in a lecture, confronted with a lot of new information, many students assume that their priority must be to record what the lecturer says rather than attempt to understand it.
They tend to make notes mechanically, thinking that if only they can 'get it all down now' they can try to make sense of it later. Unfortunately this may reinforce habits of surface learning and it is not uncommon to find students with very full notebooks who have only a superficial understanding of the material they have supposedly learned.
Here are some practical ways of helping students to learn in lectures:
a) Break up the lecture period. Interrupt the presentation of material every 15 minutes or so for a quick summary, a short question-and-answer session etc. Short breaks like this help students to concentrate better on the next part of the lecture.
b) Don't present too much information. If you need to convey a lot of data, facts or formulae, do so on handouts instead. Use the lecture to explain the information by pointing out the key issues or setting it in context.
c) Challenge students to think. Lectures can be a good means of posing questions, rather than just giving answers. Point out inconsistencies in the material, or unresolved issues. Try to engage students' curiosity in wanting to find out more.
d) Repeat yourself. As a rough rule of thumb, repeat key points at least two or three times, making clear that these are the essentials that you want students to note. It is a good idea to end each lecture with a 5-10 minute summary, reminding students of the main topics you have covered and the key points you have made.
e) Encourage good note taking. Either in your own teaching or through a study skills course, ensure that students use their notes not merely to record what you say but also to note questions, points for follow-up, connections with other topics etc. You can facilitate note taking by displaying, on the board or screen, the 'headlines' of your lecture, so that students can keep these in mind and you can refer to them as you proceed.