What is the principle of siphoning?

　　Principle summary: It is due to the pressure difference. When the pressures at the same liquid level on both sides of the bent pipe are different, the liquid in the pipe flows toward the side with the lower pressure. Overview: Siphoning is not entirely caused by atmospheric pressure; it can also occur in a vacuum. The force that drives the liquid upward is the cohesive force between molecules within the liquid. During siphoning, more liquid flows out of the tube than flows into it, resulting in an imbalance in gravitational forces on either side, which allows the liquid to continue flowing in one direction. As the liquid rises up the tube, the pressure decreases. If the tube is very tall, the pressure drops to such an extent that bubbles (composed of air or other gases) form inside the tube. The maximum height at which siphoning can occur is determined by the formation of these bubbles. Bubbles break the continuity of the liquid, as the force between gas molecules at the ends of the bubbles becomes zero, thereby disrupting the siphoning process; therefore, the tube must be filled with water. Under normal atmospheric pressure, siphoning works better than in a vacuum, as the atmospheric pressure acting on both ends of the tube increases the pressure throughout the tube. Imagine a solar collector filled with cold water; when the solar collector absorbs sunlight, the water heats up, expands, and its density decreases, causing it to rise to the heat exchanger above. The denser cold water then flows back to the bottom of the collector; after absorbing heat, it continues to expand and rise. This thermal cycling phenomenon is known as the thermosiphon effect, and the greater the temperature difference between the collector and the heat exchanger, the faster the circulation of water between them. 　　　　To utilize the siphon principle, three conditions must be met: 1. The tube must first be filled with liquid; 2. The height of the highest point in the tube above the water surface in the upper container must not exceed the height of the water column that can be supported by atmospheric pressure. 　　3. The outlet must be lower than the water level in the upper container. This results in the liquid sheet at the outlet being subjected to a downward pressure (atmospheric pressure plus the pressure of the water) that is greater than the upward atmospheric pressure. Ensure the flow of water.

Very detailed and easy to understand, thank you!