What could be better than cooling off with cool showers in the bathroom on hot days, except for the annoying curtain that sticks to you when you get out of the shower. Why does this always happen?
The answer to this phenomenon belongs to the physical category.
"Because a curtain is large but light, they will interact with the small vacuum created in the bathroom, " explains Ohle Claussen of the Max Planck Self-Motivating and Self-organizing Institute. There will be at least two physical effects leading to this phenomenon when you take a bath.
You can easily create a similar vacuum by taking a thin piece of paper or receipt and holding it on the edge of your lower lip. If you blow hard, the piece of paper will not be pressed down, but vice versa. You can see this phenomenon in the image below.
If you blow hard, the piece of paper will not be pressed down, but vice versa.
What happens in the test is called the Bernoulli effect , which is part of the reason why the plane can fly. Mathematician Daniel Bernoulli describes that in a space where the velocity of fluid is higher than its surroundings, the air pressure there will always be lower than its surroundings.
Therefore, if you blow the piece of paper hard, the air velocity at the top will be higher than the underside of the paper because most of the air below will only move very slightly. This reduces the pressure of air above the paper surface, creating a vacuum to draw the paper upwards. The "friendly" shower curtain phenomenon also originates from this.
"When air enters an area with a higher fluid rate, it must accelerate to accommodate this velocity. In fluid mechanics, such acceleration is combined with a decrease in the forming pressure. The additional kinetic energy that air particles receive is due to the high air pressure in the area of the fluid at a slow rate, which affects these air particles as they reach the fluid faster. , " Claussen explained.
Therefore, pressure and speed are always related to each other where the air flow occurs. The place with the highest speed is always the place with the lowest pressure. "So if your shower head spits water at high speed in the bathroom, the air in it will be carried away. Therefore, the air from outside must flow into the shower room and accelerate, leading to a decrease in pressure , " according to Claussen.
David Schmidt, a scientist from Massachusetts, highlighted the second cause of pressure drop, based on a computer that simulates the motion of water droplets. It shows that the water droplets of the shower spray create a eddy current, which also contributes to reducing the pressure in the air.
Shower curtains will work with the small vacuum created in the bathroom, causing them to stick to us.
This effect is just as great as the Bernoulli effect, according to Claussen. This discovery, made in 2001, shows that even a small impact, but the large but light curtain can be separated from you even under the slightest pressure.
The more the air brings the curtain closer to the body, the stronger the Bernoulli effect is: The same amount of air must flow through a smaller opening and therefore must flow even faster in that small area. This reduces the pressure at the approach point until a collision occurs.
So, try attaching some heavy objects under the curtain, threading a lead on its edge or sticking the curtain to the sink with water !