Design Your Tap

[genepeer]

At the very core, a tap changes the volume of water getting out per second (let's call that vps) and I used to think it does this by changing the size of a hole. However, it occurred to me that changing size of the hole wouldn't change the vps. Making the hole smaller will make the water come out faster and the two effects will cancel out each other, leaving vps the same.

So how does it do it? Never mind that question, if you were to design your own tap, how would you make it do it? I'm still thinking of it; will post a solution if I get one.

Googling how taps work will only limit your creativity; do it at your own risk.

PS: Or maybe my reasoning is wrong, and the tap simply changes the size of a hole. Then this topic is pointless

[Drake Glau]

I think changing the size of the hole would work just fine. I see how you mean that changing the size of the whole would just increase the pressure of the water and simply increase the speed of the water coming out and so the vps wouldn't change at all. But if you put your thumb over a hose for example that's on full blast a lot of the force goes into your thumb as it gets harder and harder to hold it there. If some of the pressure/force is lost to you thumb now instead of going with the water less water might get through the smaller hole.

Another thought I had was maybe having multiple chambers? Like a tube with a small diameter that opens into a large chamber, back into a small tube, back to a large chamber and then out the spout. Thought behind this was the extra pressure would put water into the chambers quickly but then because the chambers open up the pressure would quickly decrease and slow the vps? I'm not sure about this one. Combine these two ideas (assuming they work of course) and I think you could easily control the vps with the size of the last hole.

[genepeer]

True that, nothing ever works so perfectly as I suggested. Plus, when the hole is incredibly small, so is the vps. So what is the relation between area of the hole and vps? Are they directly proportional? I think they have an exponential relation (like an inverted half-life curve) and if I'm right, wouldn't it still be difficult to control vps at the beginning (the steep area on the curve)? How would you change the size of the hole then?

An experiment to investigate the relationship of the area of a hole and vps would help us here; Anyone interested in doing this for an IA? lol. Anyway, wouldn't this topic have been good for an EE? You explain the problem and carry out an experiment to find the relation between hole-size and vps. Use your results to design a couple of tap-prototypes and discuss how they'd work. Finally, explain how a typical tap works, compare it with your designs, and suggest improvements.