I looked through the topic list in Britannica and chose "global warming."
That's a good topic but it's too big for just one presentation. Let's take a closer look at the information in the encyclopedia entry for that topic.
Global Warming Sample Entry below.
After reading an entry like this, you may find you have unanswered questions about the topic. These kinds of questions are excellent leads for narrowing and focusing the thesis for your presentation.
These kinds of questions are excellent leads for narrowing and focusing the thesis for your presentation. Look below at the Question Focusing Table to see how focusing your topic works.
You can use one of Penfield's encyclopedias to learn more about your topic.
When you have narrowed your topic and come up with a focused thesis statement, you can continue on to the last section, Thesis Statements.
Global Warming Sample Entry