Explainer on Instagram: "The post showcases a DIY bell siphon hack, where a plastic cup inverted over a hot tub drain with an attached tube initiates water drainage without electricity, amassing over 10 million views for its clever fluid dynamics demo. It operates on Bernoulli's principle and atmospheric pressure: water exiting the tube creates a partial vacuum inside the cup, drawing in surrounding water until air enters the tube and halts the flow, as confirmed by aquaponics engineering source