In this case, the vial of vaccine rivets because we think it's scarce--availability is limited at the moment, and focused on high-risk groups. Just showing the vial underscores that it's available--not a mythical thing, in an epidemic where so many myths are spreading.
You can use props as evidence, as visual aids, as eye candy, or as extra emphasis. But keep in mind these tips:
- Use props with care. Props shouldn't be appearing every few minutes in your speech. Think judicious use, to underscore a key point--perhaps right at the start of your presentation, or at a critical moment.
- Keep it universal--and clear. A picture may be worth a thousand words, but you won't have that many to explain what you have in your hand. Make sure it's visible, understandable and clear to get the value you seek.
- Share the prop. If possible, hand the prop around for the audience to handle up close. If it's the right kind of prop--historic, unusual, or new-t0-them--you'll be reinforcing your talk as they pass it around, without too much loss of attention. (Not good for vaccines, I'm afraid.)
Here's the video of the full piece, with thanks to MSNBC.com for making embedded video possible. Dr. Caine comes in at about 49 seconds: