Against Physics? Ahh..nothing can work against Physics
When we bought this house, its interior including bathrooms and kitchen had only bare walls with no fittings. I had to make each part of the house functional. It was a difficult work, for I knew none in the neighborhood, never had any experience of this kind of job, had no adviser and had to engage workmen like carpenter, wall painter or plumber from somewhere as well as oversee their work.
This story started when my green-horn plumber was trying to equip my second bathroom with the usual fittings. After somehow he finished all else, when I showed him the small geyser he said with total emphasis, "It cannot be fitted in this bathroom. You won't get any hot water in your shower."
The problem of geyser lower than the shower
The problem lay with the six and half feet low ceiling of the bathroom. On top of the bathroom was the loft and the shower was just below the low ceiling. Truly, there was no way a geyser can be fixed on the wall well above the shower.
The awkward and unacceptable solution
His first suggestion was to fix the geyser above the ceiling on the loft floor and make a hole on the ceiling for the pipes down into the bathroom. It was a preposterous solution and I couldn't accept it. It was a deadlock.
I still remember those few minutes when I saw in my mind the two more storeys lying above my ground floor roof and the fair-sized water tank secure on the staircase mumptee another ten feet higher. All in all the house-top water tank was at least 40 feet high from ground.
This kind of visualization enables clarity.
I made the plumber fix the geyser on the same wall as the shower. The geyser height finally was lower than the shower.
When I switched on the geyser for a few minutes, and then the shower, the plumber stood transfixed with warm water from the shower spraying over his outstretched hand.
That was seven years back.
Subsequently experienced plumbers and visitors came, saw and went away very surprised. None could believe or predict the outcome till they actually felt the warm water coming out of the shower.
Let me show you the picture to give you a feeling of the situation.
Can water flow upwards?
The answer is a firm Yes. Though it is against common sense, it certainly happens by human-known physical laws (there certainly are many physical laws that are yet unknown). After all, common sense is created from common experience gathered throughout life.
I know of two cases (leaving aside the surface tension case),
When water is warmed, it goes up replacing the cold water above, because warm water is lighter than cold water. This is a great property of water and used as an Innovation in the forest so many decades ago.
When water is stored in a tank A at a higher level than a second tank B at a lower level, the water pressure of the higher tank would be higher than the water pressure of the lower tank. If the two are connected by a pipe, water will flow down from higher tank A to the lower tank B. This is known perhaps to everyone. This property simply says, "Water flows downwards". But what happens if a third tank C is placed between the first two above the second tank and is connected to the second tank which is at a lower level than the third?
Water simply flows down from tank A to tank B and then forced upwards to C by the higher transmitted pressure from A above. This is principle of pressure.
Though in reality the situation is not that simple—there is a loss of pressure in the geyser, like voltage drop across a resistor. But the roof-top tank supplied enough pressure for the system to work fine.
And it didn't seem to me very extraordinary till my friend from Dharamshala staying with us came out of the bathroom and exclaimed, "Something in your house is working against Physics."
So after all, principle of pressure is not so apparent, particularly if the hand lying far above us pressing down is invisible, I thought.