A student asked me, "What's the difference between presentations, teaching, and public speaking?" Well... that's a great question!
The simplest way to distinguish them is by the duration of time involved. Presentations are typically shorter, usually lasting under 20 minutes (brief and concise). Teaching, on the other hand, usually spans over an hour or more (ranging from 1 hour to a full day), and public speaking offers more flexibility, often falling within the range of 1 to 3 hours (90 minutes being quite suitable). Let's analyze the unique characteristics and key considerations for each of these.
Due to their shorter time frame, presentations rely on one-way communication, aiming for brevity, simplicity, and impact. Ideally, the audience should trust and not question what the presenter conveys (think of examples like Apple's presentations). The core focus of a presentation is to persuade the listeners and have them accept the ideas being presented. With the limited time available, the audience can usually maintain their attention. If the delivery is compelling and the content is tightly packed, often the time ends before the audience even realizes it.
However, the short duration also poses a challenge. The faster the pace of the presentation (with more slides), the less room there is for mistakes. Presenters must practice extensively beforehand to control the timing and rhythm of their presentations. If any part of the presentation falls behind schedule (typically at the beginning), the subsequent sections may either run out of time or be rushed, which is something to be particularly cautious about.
Of course, there are different levels of proficiency expected in presentations, ranging from fundamental skills to seeking variations and striving for perfection. Practicing extensively is essential for delivering a good presentation. We won't discuss the dreadful combination of reading from a script and poor slide design... let's leave that aside for now.
A skilled presenter doesn't necessarily make a good teacher! Imagine a presentation expert delivering a three-hour class at the same rapid pace as a presentation... even if they speak fluently and their slides transition seamlessly, do you think the class would be exhausting? (The answer is: yes! And not just for the students, but for the presenter as well.)
The essence of teaching lies in learning, and the focus is not solely on how well the teacher delivers the content, but rather on how much the students can change and grow. Based on my experience and observations, the effectiveness of the lecture-style approach (which is akin to presentations) is actually quite limited. Even if the speaker is engaging and dynamic on stage, for the students, it often becomes a passive listening experience that can be tiresome over time. Moreover, it is not easily translated into personal experiences, as students may seem to understand everything in the moment but fail to recall when questioned later. This does not lead to effective learning outcomes.
Therefore, effective presentation skills (lecturing) are only part of the teaching process. Apart from lecturing, are there other instructional methods that can be employed? For example, questioning and answering, group discussions, case studies, hands-on exercises, videos, post-class assignments and reports, and practical demonstrations by the instructor. There are various teaching techniques that can be planned and chosen. The goal for teachers should be to speak less while ensuring that students learn more. This is something that a good teacher should ponder upon. Some of the best teachers I've encountered may not excel in presentation skills (they aren't fast talkers), but their course design and instructional techniques have left an indelible impression on me (classes were engaging, filled with practical exercises, and sparked intense discussions). Even today, I remember the content of their classes vividly. That's what makes a truly exceptional teacher!
This aspect is also crucial for businesses when training their internal trainers. Being a trainer does not necessarily equate to being a charismatic speaker, and being skilled at presentations does not automatically make one a good teacher.
Public speaking allows for greater flexibility in its execution. Sometimes it resembles a presentation (more one-way communication with a faster pace), while other times it can incorporate elements of teaching (interaction and discussions), depending on how the speaker designs it. If you excel at speaking (storytelling, examples, and captivating presentations), I believe a 90-minute session can be filled with humor and be exceptionally engaging. If you have ample experience, you can also introduce interactive teaching methods during the speech (such as Harvard's Justice class, which is essentially a lecture-style teaching). You can incorporate question and answer sessions, group discussions, or use small incentives to stimulate interaction.
Take the HPX 17 lecture in March 2011 as an example. Essentially, it was a speech (90 minutes with an audience of over 100 people). I used a presentation as the foundation (slides, videos, rapid transitions, a total of 172 slides) and blended in interactive teaching techniques (leading Q&A sessions and discussions, and utilizing group mechanisms). The results were quite favorable. As time went on, I introduced more interactive elements, as sitting for too long can cause people to lose focus, and the effectiveness of the speech or teaching would diminish. (The two photos above were from the same speech: initially, everyone was sitting upright, and then things got busy.)
Another example is the Presentation Skills Summit in June 2013, which was a speech based primarily on a presentation. Due to the shorter duration (30 minutes for the first session, 20 minutes for the second), I included fewer teaching elements and operated at a faster pace. However, even in the 30-minute speech of the first session, there were still some interactive learning components, which received positive feedback afterward.
Presentations emphasize a brisk pace, while classes focus on interactive learning, and speeches can choose one of these techniques or combine them. The key is thorough preparation and ample practice! (The emphasis is not on what you say, but on what the audience remembers....!)