Responding to the Flat Earth '£100 Street Challenge'

I'm sure if you have a passing interest in skepticism and the intersection of pseudo-science and actual science you won't have failed to notice the rise in popularity of belief in a flat-earth. April this year saw the largest gathering of flat-earthers ever held in Great Britain and similar meetings have been held across the Atlantic. As such, it's important that science communicators don't ignore the claims made by flat-earthers. 

With that I mind I decided to take a look at a specific claim made by a Youtube group known as Beyond the imaginary curve posed in what they call "the £100 street challenge". The claim specifically relates to the idea that water "doesn't bend". Flat-earthers argue that because water cannot be made to curve to a surface on a small scale, this must imply that water would simply "run off the sides" of a globe earth. This is often demonstrated by flat-earthers pouring water over the surface of a ball or balloon.

Yes, I know. It's stupid. But lots of people take flat-earth rhetoric very seriously, so let's do the same and unpack the claim in detail.

In the Street challenge, we see Del of  Beyond the imaginary curve approaching members of the general public with a bottle half-filled with water. He offers them £100 if they can bend the bottle in such a way that surface of the water follows the curve of the bottle rather than remaining flat. Of course, water won't do this. This means, argues Del, that water will never curve in such a way and thus the Earth is not globe-shaped.

It's a pretty easy claim to debunk. Let's do so in the form of a video.

References

(1) https://www.youtube.com/watch?v=9VzItwtS9Gc&t=216s

(2) https://www.scientificamerican.com/article/static-electricity-bring-science-home/

(3) https://www.youtube.com/watch?v=VhWQ-r1LYXY