It’s surprising what scientific principles are illustrated when taking a shower. Here are three that I have observed recently:
Do you remember those 1980s showers that were fed (via the hot water cylinder) from the cold water cistern in the roof? The cold water storage tank was only a few feet above the shower, so there was insufficient water pressure to give a decent flow at the shower.
This is Potential energy, where the height of the water tank determines the pressure of water at the shower. A slightly better shower could be achieved by squatting down, and so increasing the height difference – however this was not a very comfortable position to stay in for long.
I have one of those electric showers that heats the water as it flows through. The temperature control adjusts the water flow. The faster the water flows, the cooler the shower. Increasing the temperature means decreasing the water flow and vice-versa.
Sometimes an acceptable shower becomes a compromise: I can have more water but lower temperature, or higher temperature but less water. This is an economic principle called Pareto efficiency which roughly means “you can’t make one thing better without making something else worse”. And yes, economics is a science – a social science.
And finally, have you ever had one of those showers where the shower curtain is intent on wrapping itself around you? This is the Venturi effect. In a nutshell, the water in the shower hose is under pressure – there is lots of water compressed into a small space. As the water emerges from the shower head it spreads out into the area of the shower spray and the pressure drops. Consequently, the air pressure inside the shower curtain is lower than outside, and the curtain is sucked in.
To solve this problem, move the curtain rail down the wall a bit so that there is a gap between the top of the curtain and the ceiling. Now the pressures can equalise and the curtain stays where it is.
Right. People are hammering on the bathroom door. I think I’ve been in the shower for quite long enough now.