Differences in the behaviour of pinching a garden hose and closing a tap Let's say you have a garden hose connected to an ordinary water tap which is opened fully. If you pinch the end of the hose, water leaves the hose at a higher speed (and this can be useful while watering plants, to reach pots which are further away). However when a tap (with no hose connected) is opened only slightly, water flows out at a low speed, possibly even in drops.
The actions of pinching the end of a hose and of almost-closing an open tap seem similar, so why the difference in behaviour?
 A: This diagram shows the difference between closing the tap and pinchng the end of the hose:

In both cases you are reducing the area the water has to flow through, and this increases the water velocity in the constriction. The upper diagram shows what happens when you close the tap. Closing the tap increases the velocity of the water at the constriction, but as soon as the water is past the constriction is slows down again and it emerges from the end of the hosepipe with a relatively low velocity.
The lower diagram shows what happens when you pinch the end of the pipe. The constriction increases the velocity of the water but because the constriction is right at the end the water doesn't have a chance to slow down again so it leaves the end of the pipe with a relatively high velocity.
A: 
As shown in the figure, the gap of the faucet is inside the faucet, and the direction of spraying water is shown by the red arrow. Although the speed of the water in the gap is relatively large, the arrows are opposite to each other, so the speeds cancel each other out, so you are at the exit of the faucet. No high speed can be seen. At the end of the hose, the speed of the water passing through the gap can be seen. Why is the gap velocity high? Because the gap reduces the flow rate upstream of the hose, the static pressure of the water inside the hose increases, so the water at the gap obtains a greater thrust. So the speed increases.
A: When pinching the hose, the pressure slightly expands the diameter of the hose.  When you release the pinch in the hose, the water has greater velocity for two reasons:  1)  There is slightly greater volume in the hose because of the expanded volume of the hose 2)  The elastic response of the stretched hose, pushing the water out.
