What are some real life demonstrations of black holes?

[AviSchiffmann]

Hi, I am working on a video, and I was wondering if any of you knew of some real-life demonstrations I can do about black holes? So far I have the gravity well, and the balloon covered by foil that you crush to show same mass but denser. My video is about the anatomy of a black hole, so I cover all the parts from photon spheres to singularities. Do any of you know of some interesting and or funny demonstrations I can do in real life? Limited visual effects because I want less animation and more me actually doing stuff. 

Thank you!

[Silvestru]

Bathtub filled with water (maybe colourful water if you don't care about  your tub) and you pull the cork, zoom on the "vortex" kinda to show how all the "stuff" if pulled in.

Or better yet, read this:

https://www.scienceinschool.org/2013/issue27/blackholes

[Endy0816]

15 hours ago, Silvestru said:

Bathtub filled with water (maybe colourful water if you don't care about  your tub) and you pull the cork, zoom on the "vortex" kinda to show how all the "stuff" if pulled in.

Da, that's a good one. Very visually similar to the accretion disc.

[Sensei]

Quote

What are some real life demonstrations of black holes?

Some people would answer: wife and kids..