I have been preparing the Tennis Ball can experiment, but the water doesn't go quite as far as the math predicts. With a hole to top height of 18.5cm and a hole to floor height of 93.5cm I get a distance of 83cm. However, the stream is only reaching the high 70's of cm. Also, the water breaks up from a solid stream before it gets there making the exact landing point difficult to determine.
The stream breaking up is the problem, I think. In class, I've always hit the prediction dead on. But on Monday at a workshop in Alabama, I missed. See, I had quickly jury-rigged a gatorade bottle for this demo. I used my cheapo pocket knife to make a jagged hole. The stream was not particularly clean, but was breaking up. Sure enough, I missed -- I predicted 65 cm, but the stream only went 50 cm.
I suspect -- though I'll have to play around a bit to be sure -- that this demo depends on getting a "clean" stream out of the hole. After all, Bernoulli's equation explicitly is for "inviscid" flow, meaning no viscous drag.
Let me know if you try again, and I'll do the same.
Greg Jacobs teaches AP and 9th grade physics at Woodberry Forest School, the nation's premier boarding school for boys. Outside the classroom, he coaches football, and he broadcasts varsity baseball games over the internet. In his spare time, he is a reporter for STATS, LLC, he writes books about physics, baseball, and football, and he umpires high school baseball. Greg is the president of the USAYPT, which sponsors the yearly US Invitational Young Physicists Tournament.