When you're planning a podcast, whether for online learning purposes or entertainment, size does matter.

As stated elsewhere on this website, the human brain takes in information through three primary channels: through seeing, through hearing, and through touch/experience.

The brain is a mighty multitasking machine, and so when we learn, we tend to learn best when we engage all those channels.

A podcast, however, is processed solely through the brain's audio channel -- and that channel will become fatigued fairly quickly.

On average, when you produce audio material for education, your listeners will retain the knowledge best if your program is no more than 20 minutes in length. If your topic is large and complex, it's far better to break it into several 20-minute podcasts instead of producing one long show. That way, your listeners can take the information in in small doses, and rest their brains in between.

If you pay attention to commercial and public radio programming, you'll see this 20-minute model in action. Most radio programs, even when they're an hour or more in length, will break the hour up into several shorter subjects. Or, if the whole hour is about one topic, the show will be broken up into shorter segments with breaks in between.

Not to mention, when you're keeping to a 20-minute format, it forces you to keep everything about your show succinct, relevant, and purposeful. (You only have 20 minutes, after all!) And this results in a high-quality podcast.

by Diane Gilleland

Podcasting is an exciting tool for learning. It makes education portable, digestible, and readily accessible. However, as new as the medium is, very few educational podcasts are using it to full advantage.

To make good, memorable audio, you need more than a script and a microphone. You need to understand some things about how audio-learning works.

In fact, let’s back up even a little further, and consider the three channels we humans use to process information: Visual, Auditory, and Kinesthetic. Each of us favors one channel more than the others, but most of us learn best when we can use a combination of all three. We might read a textbook about, say, scuba diving, and then listen to a scuba instructor, and then take that first dive. Using all three channels, we learn very effectively.

Back to Podcasting. Given that it’s a strictly audio medium (podcasts do not have pictures), we have to consider the fact that we’re losing two communications channels. But this doesn’t have to mean that podcasting is a less-effective way to learn. It just means that you need to structure your audio so that it stimulates the Visual and Kinesthetic responses in your listeners.

How do you do this? Here are some ideas:

Create sound pictures.
Why do we love to read a great novel or adventure story? Because when we read, our brains create a picture version of the story. Pictures stimulate our Visual channel. So, present your audio in ways that trigger visual images in the minds of your listeners. Use sensory, descriptive language -- talk about color, smells, flavors, textures, temperature, and so on. Whatever your podcast subject is, consider what it looks, smells, and feels like, and bring these elements into your audio.

You can also insert “soundscapes” into your podcast to help set a scene. In a podcast about the history of railroads, for example, you can use related sounds like train whistles, the clicking of the tracks, and conductors calling “All Aboard!” The more you can get your listeners to make their own pictures while listening to your podcast, the better they will retain the material.

Use storytelling.
We humans are story magnets, and we’ve created entire industries of publishing, film, radio, and theater to support our story habit. How many times have you been in a learning environment where the instructor said, “Let me illustrate that point with a little story. . .” ?

When we’re involved in listening to a story, two things are happening: we’re using our Visual channel to (again) create pictures of the events in the narrative. We’re also activating our Kinesthetic channel a little, by placing ourselves into the story and vicariously participating the events, as if they’d really happened to us.

Storytelling is a very powerful tool for podcast learning. Why deliver a dry lecture on the legal implications of poor communication in constuction contracts when you can instead tell the story: this architect, despite good intentions, missed one crucial detail in a field report to his client. Then he found himself in the middle of a lawsuit two years later, when the building’s foundation crumbled.

Simplify.
You can facilitate audio learning by keeping your language simple. This doesn’t mean that you need to talk down to your audience. It just means that the way you use language in an audio setting is different than the way you use it in writing.

Case in point: when you’re reading a text, if you don’t understand a point, you can easily read it again. If you need a moment to process what you just read, you can look up from the page, and when you return, it will still be there.

When you listen to audio, however, it’s always moving. You can pause it, of course, or reverse it to hear something again, but that’s a bit more work than it is for written material.

So, when you’re presenting material for audio-learning, you need to make sure your audience can grasp the concepts easily. This is not the time to practice your most complex sentence structures, or use all your two-dollar words. Instead, keep sentences short. Use direct, clear language. Deliver one idea at a time, or find ways to repeat the ideas.

And, paradoxically, you need to incorporate some silences in your audio so that your listeners can have that experience of “looking up from the page for a moment.” After you present a key idea, pause for several seconds to give it a chance to sink in.

Learn to Read Aloud.
It’s a fascinating phenomenon . . . when most people read any text aloud, their voices fall into a kind of sing-song monotone, and they read very fast.

Unfortunately, that kind of vocal delivery is almost impossible for the human brain to pay attention to for long. If you’re going to deliver good audio-learning, you’ll likely be using written scripts, and if you’re reading them aloud, you have to break yourself out of the monotone.

It may help to think of the sound of your voice as a kind of landscape. If you’re speaking in a monotone, with few pauses, then that landscape looks rather, well, flat. Contrast that to how your voice sounds when you’re speaking excitedly about something very meaningful to you: your voice has lots of high tones and low tones, and speeding up and slowing down, and energy, and pauses. In short, a much more interesting vocal landscape. In essence, an interesting vocal performance helps stimulate the brain’s Kinestetic channel. The brain has to stay “in motion” in order to follow the sound of an animated voice.

The best way to combat the read-aloud monotone is through practice. Rehearse your material enough times that you can deliver it without needing to read it aloud. And focus on adding energy and excitement to your vocal landscape.

Bring Visual and Kinesthetic experiences to your educational audio material, and it will become a very more effective, well-rounded teaching tool.