The January-February 2018 issue of Speaker magazine contains a useful two-page article by Tim Gard titled To Prop or Not to Prop? In it he lists the following four questions that define an effective prop:
1] Does the prop and how I use it add value or clarity?
2] Will 100% of my audience be able to see it?
3] Will the majority of the audience understand it?
4] Is there any possibility it will offend someone?
For more about props, look at an April 25, 2017 article by John Zimmer at Presentation Guru titled How to ‘Prop Up’ your next presentation, and a June 26, 2017 article at SlideStore titled
Props for presentation: yay or nay?
An 1899 image of magician Zan Zig came from Wikimedia Commons.