They actually pay me to do this sort of thing. -- V. Berg
The Parthenon is the most famous building in the world. It is known for its beauty and symmetry, and has managed to survive as a model of design. Many people, wishing to make their endeavors sound higher class, use the name as part of their identity. Here we are doing the same, hoping to make a classic (if not classical) science presentation, or at least one with class.
1. A presentation, like a building, has to be built from the ground up. So the first task is to lay the foundation with the general topic to be addressed, including why it is interesting (or ought to be) and important.
2. Then we have to get more specific, and address the particular topic we will focus on.
3. Next, we have to tell the listeners what to expect, in terms of the subtopics we will tell them about. For this example, we are going to tell them about 4 subtopics (perhaps experiments).
4. Now it is time to tell each of the four "stories" within the specific topic. One at a time, we build each one with a chain of information, each bit building on the previous ones. At the end of each story we crown it with a major point we learn from it. Each time you start on a subtopic, you might refer to the set of subtopics to show the listener where you are in the talk.
then the other stories in turn, until we get
5. The time has come to tie the stories together: comparisons and contrasts go here, as well as reference to the questions presented in the general and specific topic introductions. Notice how this section rests on your individual stories.
6. The last thing you have to do is to guide your listeners to a single important take-home lesson or point or conclusion. If they are to remember only one thing, what do you want it to be? Don't assume they will come up with this by themselves.
If you compare our construction with the Parthenon again, you will see our lines aren't quite as good, but that we have followed the general idea. There are other ways to structure a science presentation, but this one is pretty easy to remember and to do, and it works.