You can use the Twitter 164 character in classroom sessions by doing 90 seconds micro-discussions.
Before or after a key small point in your present ask your audience to have a 90 seconds discussion. Each person finds another person and they have each 90 seconds to talk about the issue.
Ask a question to your audience to discuss.
Debrief, ask only 1-3 people to share discussions.
Just like Twitter, if you have 3 to 5 90 second micro-discussions, ask the group each time to find another partner, that way they see many perspective.
The room of 150 people at my session at ASTD Tech was hmmming with chatters, like Twitter.
The only problem sometimes, once in a while, face to face twitter, there's a risk of getting a spit on your face.
Everyone loved it.
Try it and let me know.
Ray Jimenez, PhD
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