To put across a point with more effect.
To help trainees take more in - as mentioned above up to 75 % of knowledge or information is gained through sight.
To maintain interest.
To focus attention on one spot or in one place.
To break up a lecture, particularly every 20 minutes.
To help in the preparation of a talk - extensive preparation leads to a polished product.
To help keep both the speaker and the audience on track.
To aid memory by providing a summary.
To help standardise presentations involving a number of trainers at different locations.
To add variety.