Why is this weird?
Don’t get me wrong - it looked weird to me at first. I watched the slo-mo and thought “It’s like it knows where the edge of the beaker is, and it’s avoiding it”. But I thought for a bit, and using the same arguments that the Science Guy did, reasoned that (a) the chain must be initially going up at pretty much the same rate as the bit outside is going down (b) it would need a pretty hard tug to get it moving that fast © the chain can only apply a force along its length, so it must move in an arc for the tension to change it from going up to going down without any other forces. Long story short: it would be surprising if it didn’t do something like this.
Think about gyroscopes. Common sense can be pretty rubbish at times.
