What Is The Principle Of The Watering Can?

Use the principle of atmospheric pressure to spray water.
When pumping air into the jug, the air pressure inside the jug rises, and there is pressure on the outside. If the button is pressed, the water will be sprayed out through the hose.
Reasons for not spraying:
1. There is too little water and there is no contact with the hose
2. Too much water
3. Too little gas