#SwimmingPool #ColdWater #Thermodynamics #WaterTemperature #PoolPhysics
You know that feeling when you first dip your toes into a swimming pool and the water feels absolutely freezing? But after a while, when you’re fully submerged, it actually starts to feel warm and comfortable. Have you ever wondered why that happens? Let’s dive into the science behind it!
##The Initial Cold Shock
When you first step into a swimming pool, your body experiences a sudden shock from the cold water. This is due to a few different factors:
1. **Heat Transfer**: Water has a higher thermal conductivity than air, which means it can conduct heat away from your body much more efficiently. So when you first come into contact with the water, it pulls heat away from your skin at a faster rate, making it feel colder than the surrounding air.
2. **Thermodynamics**: Water has a higher specific heat capacity than air, which means it takes longer to heat up or cool down. So even if the air and water are at the same temperature, the water will still feel colder due to its higher heat capacity.
3. **Evaporative Cooling**: As the water evaporates from your skin, it takes away heat, further contributing to the initial cold sensation.
##The Warming Sensation
But as you spend more time in the water, your body begins to adjust and acclimate to the temperature. Here’s why the water starts to feel warmer over time:
1. **Thermal Adaptation**: Your body is constantly producing heat, and as you stay in the water, the heat that is being lost to the water decreases. As a result, your body starts to feel warmer in comparison to the cooler water.
2. **Vasoconstriction and Vasodilation**: Initially, your blood vessels constrict in response to the cold water, which helps to conserve heat. However, as your body adapts, your blood vessels dilate, allowing for better circulation and heat distribution, making the water feel warmer.
3. **Nerve Desensitization**: Your nerves start to adapt to the cold stimulus, causing them to become less responsive to the sensation of cold. This desensitization leads to a perception of warmth in the water.
##Conclusion
So, there you have it – the science behind why a swimming pool feels cold initially but warm after a while. It all comes down to the way your body interacts with the water and how it adapts to the temperature over time. Although the initial shock of cold water can be a bit jarring, once your body adjusts, you can enjoy the warm and soothing sensation of swimming. So next time you take a dip, remember that it’s all about the fascinating dynamics of heat transfer, thermodynamics, and your body’s ability to adapt to its environment. Happy swimming! 🏊♂️🌊🌞
###Keywords
– Swimming pool temperature
– Why does a pool feel cold at first but warm after a while
– Pool water thermodynamics
– How body reacts to cold water
– Warm sensation in swimming pool
You acclamate. The single biggest change is that you reduce the amount of blood going to your extremities so that you do not lose heat as quickly.
You don’t really feel how hot or cold the environment is. What you feel is how quickly you are gaining or losing heat. So when you make some adjustments so that you are not losing heat as fast you don’t feel as cold.
Technically, your body does not have the ability to sense how hot/cold other things are. You sense temperature by how much your own skin changes in temperature. So you were very warm on a summer day, touching cold water chilled your skin greatly and you felt that. But then you stayed in the water, and your body cooled down, and now your skin temperature isn’t that far off from the water. It’s not changing much so you don’t sense it anymore.
This same effect is why you feel so cold with a fever. The air is now cooler than your skin making you feel cold, when it wasn’t the air rust changed.
The temperature you feel isn’t really about the actual temperature of your environment (the water in the pool). It’s about the rate of energy transfer. If the pool is much colder than your skin, the rate of transfer is high, so you feel cold. Once you’ve been in the pool for a while, your skin temp has already come down so the rate is slower, so you don’t feel as cold.
A side tip, if you cool down the water in your shower a bit before you finish, when you step out you will feel less cold because your skin isn’t super warm from the hot shower
Thermodynamics
It’s very similar to why a metal table and a plastic table can both be 18c but the metal one feels so much colder, and that’s heat capacity and conductance.
Water is great at storing heat and it also conducts it fairly well this means water can pull a lot of heat energy out of you very fast making it feel like it’s colder then the air
It isn’t the water temp that does that. It’s the air temp. If the air temp is warm, the water will initially feel cold.
Heat transfer equation:
Q = k * A * ΔT
The bigger the temperature difference (ΔT) the more heat transfer. When you first jump in the temperature of your skin is around 30-31 C and the water is much colder so the heat transfers quickly, which you sense as “cold”. But once your skin temperature has reduced and is closer to the water temperature the ΔT is smaller therefore the rate of heat transfer is less, so you sense that as “less cold”
No one has yet mentioned why the water feels *warmer* than the outside air for a while, why is that?
Generally, when you go swimming, the water IS colder than the air, which is part of the reason why it feels cold when you get it. It generally is colder because it has a higher specific heat which means it takes more energy to heat it up than it does to heat air up, so it tends to hold much more stabile temperatures than the air.
But even if the air and water are the same temp, the water will feel colder because once again the water has a higher specific heat than air so the water immediately touching your body will take more heat energy from your skin to warm up.
When you get out, you’re covered in water, and it will start to evaporate off your skin, which is an endothermic process, which means it takes energy from your skin. You interpret this removal of heat eventfully from your skin as feeling cold. This is also how sweating cools you down.
ELI5: Water feels colder when you get in because it it usually IS, and air feels cold when you get out because water is evaporating off your skin
You get in and the water is cooler than your body, so it feels cold. Then you match so you no longer feel cold. When you are wet and not submerged, the water evaporates off you and takes your body heat with it, cooling you. When you re-submerge, it feels warm now because of that lost heat.
Its all comparative.
Your body does not feel temperature, it feels change in temperature.
After a while your skins temperature drops to that of the water, when this happens it feels warm.
Partly homeostasis, partly exercise increasing body heat. Your body temperature is going to be higher than any pool not heated to 95 degrees so your skin will register the wetness as ‘cold’. When the wet sensation is your environment, and you have raised your body temp by swimming, you don’t sense the water in the same way on your skin, and your internal temp is also elevated.
You cool your body when exercising by sweating – the evaporating water lowers your skin temp.
Acclamation. Why does a good cup of warm coffee taste bad after 20min when left at room temp vs why does a cold milkshake taste gross after 20min in room temp.
It does???
I’ve never ~~stayed in~~ got into a freezing cold pool long enough to find out.
Big toe says “Noooo!”.
Your senses get used to and recalibrate to constant stimuli. It helps prevent the brain from getting overwhelmed.
With smell it is known as nose blindness. Where you can no longer notice the smell of your feet, home, old gym clothes etc.
Your ears do the same thing. If you go into a place with lots of machinery you eventually tune out the noise. It’s why OSHA demands hearing protection above a certain decibel level.
Taste: eat some candy and then try some fruit. The fruit will taste bland.
sight: Your eyes have three different cone cels that react to different wavelengths of light. If one cone gets overstimulated you will see an afterimage in the opposite color once the stimulus is removed.
Upon entering cold water, your nerves send a massive amount of signals to your brain, triggering your bladder to release the warm urine from within.
I think of it this way: your body is pretty well-adapted to dealing with temperature variation, at least in a narrow range. You have multiple sets of sensors.
The temperature-sensing nerves on the surface of your skin are your early-warning system. They react mostly to _changes_ in temperature. You’re outside on a warm or hot summer day, so the blood vessels in your skin dilate and you probably sweat to cool off.
A dip in swimming pool starts to look awfully good. You didn’t _learn_ that – it’s instinct!
But the water is cold. It takes a minute or so for your skin to react: your capillaries constrict and your skin transforms from a radiator to an insulator as its temperature approaches the water temp. Then you stop feeling the cold and can swim comfortably!
Your core temperature changes much more slowly. Here, your body doesn’t sense the change in temperature as much as it does the difference between your “set point” – the temperature your brain is trying to maintain, and your actual (blood) temperature. You swim a while and then start to feel like you need to be warm again. Children cool off more quickly.
A fever bumps your set point up. While you’re getting a fever you feel cold, even shiver. You’re already hot but your brain wants you hotter-so you get under that blanket!
Then you feel crappy because your body isn’t designed to operate at 104 F. Your body hopes that whatever is making you ill likes that heat even less than you do.
When the fever breaks, your set point drops to normal and you’re _roasting_. You sweat profusely. For a few days afterwards, you become particularly temperature-sensitive as things stabilize again.
When the fever
You know when you walk from a bright room in to a dark room and you can’t see anything, but you can slowly perceive more and more after a while? That is your eyes adjusting to the new conditions which takes a few minutes.
It is a similar effect (although an entirely different mechanism) to your skin adjusting to the new conditions going from warm air to cold water.