Once you have determined what equipment you have at your disposal and what types of visual aids you can successfully present to your audience size, you must determine what part or parts of your speech would most benefit from a visual aid. In general, speeches that include numerical data or series of statistics presented for comparison will benefit from the use of charts or graphs. A visual aid will help anytime you are describing a physical or mental process, a spatial relationship, or a complex system. For example, in describing the cell cycle, it would save time to visually represent each phase rather than try to explain them with words alone. It would take much longer to describe the chromosome movement, the process from late-prophase through late anaphase and telophase, and leave your audience with a clear concept of the whole process without using visual aids.
Videos are also useful for showing processes.
In addition to making different points in your speech clear, visual aids can also be used to add some dramatic effect or leave a distinct impression on the audience. For example, if you are giving a speech about the holocaust, photographs of what you are describing could leave an incredible impression. Or, consider how flat a speech on 20th century art would be if no examples were shown to the audience. On the other hand, it is important to keep in mind that not all speeches will benefit from the use of visual aids. Visual aids can also detract from your speech if they aren t useful in elucidating one of your points.