The second step Rowan suggests is to follow up the typical exemplar with a definition. Because concepts can be vague and involved, limit your speech to aspects that can be readily explained and understood within the time limits.
Speeches about Processes Speeches about processes focus on patterns of action. Like most informative speeches, a how-to speech will likely use visual examples that show the audience how to move from step to step through a particular activity.
Your goal is to serve the interests and needs of your audience, whoever they are and whether you believe they already know something about your topic. For the circulatory system, you could show a video or diagram of the entire system or make an analogy to a pump.
Narrow your topic in a different way. Therefore, if you choose a topic that turns out to be too difficult, you must decide what will serve the needs and interests of the audience. Each of these examples lends itself to multiple types of information.
Other examples of speeches about processes include: how the Internet works not "how to work the Internet"how to construct a good informative speech, and how to research the job market.
A definition speech explains the meaning, theory, or philosophy of a specific topic that the audience likely does not know much about. More frequently, however, you will use process speeches to explain a process in broader terms.
Speeches about Events Speeches about events focus on things that happened, are happening, or will happen. Then you can move to explaining relationships among the components of the process. This might also be the sort of topic that would strongly serve the needs of your audience before they find themselves in trouble.