DENJIRO: Roughly 2,000 years ago, there was an interesting fountain in Ancient Greece. It's called “Heron's fountain," and it was invented by the mathematician Heron. It uses no power source such as a pump. The water that shoots out is being collected in a bowl, so it looks like the water is circulating.
Let me explain using this model here. The two containers represent the two flasks. The triangular part represents the bowl. Let me pour some water in it. Blue water is shooting out from the top. The pipe on the left is connected to the container on the bottom and filled with water, so there's essentially a column of water. Due to the height of this column, water pressure is applied to the container on the bottom, and air is getting compressed. The pipe on the right is filled with air and not water. The water on the top container gets pushed by the compressed air, and spurts out as a fountain. The water is only moving from top to bottom, so unfortunately, when the container on top becomes empty, the fountain will stop.
The amount of air pressure that is pushing the water out depends on the height of the water column. The bigger the height difference, the higher the water will spurt out, but this might not be easy to do. So, I came up with a better solution. It's a Heron's fountain with multiple tubes linked together. Let's see how high the water will shoot up.
You don't need a big height difference. You can just connect multiple tubes together to increase the air pressure.
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