Overhead projector casts an images of the transparencies on a screen. Transparencies are frequently used visual aids especially when audience is large. With sketch pens or color pencils matter can be written on them. The better way is to write in block letter or draw graphs etc, in computer and have their print ( either through photo state machine or laser printing ) on transparencies.
Transparencies are a effective means of projecting graph charts or data on the scene which are visible to the large audience. Presented matter can be erased and transparencies can be reused for new presentations or they can be stored for further use.
To make it more effective:
a.Pay attention to the focusing.
b.Show transparencies only when they are discussed.
c.Use paper or cardboards to cover the parts yet to be discussed.
d.Face the audience as you speak.