Evaporation Explained


apparently, the animal's instincts toward seeking a cooling shower are also misguided

Recently, a woman with many, MANY years of horse experience told me I shouldn’t turn my horse outside after a bath because “water is an insulator and will keep them hot.”

I never thought I would question my own logic when it came to the cooling effects of evaporation, but the ridiculousness of the statement convinced me I was suffering from hearing dyslexia.

Me: I’m sorry, what was that?
Woman: I can’t believe you do that…you know water is an insulator.

For the better part of two decades, this woman has been considered a horse “professional”.

“You know those [post ride baths] are why he’s loosing weight.”

I was dumbfounded. Had this woman never played in the lawn sprinkler as a young child? Had this woman never taken part in a rogue, neighborhood fire hydrant opening? Had she never taken a dip in a pool on a 90 degree Fahrenheit day?

Was I really going to have to explain the properties of evaporation to a woman who in the past has been paid to train and care for horses?

Answer: No. I say this a lot, and it’s especially true for the horse world, but you can’t reason with crazy people. And don’t get me wrong, I’ve heard a lot of crazy things from crazy horse people, but this was just stupid.

I stood there dumbfounded. I must have looked like a moron. After a ride and cool down in the heat of summer, I’ve never deviated from a well-deserved bath, the sweat scrape, a nice stall lunch, and turnout back to the pasture. Who was this horse woman and what planet did she come from?

She continued.
Woman: You know the water is why he’s loosing weight.


Yes, weight loss has been a problem recently; factors I had seen contributing were the new terrible hay, the heavy workload, and the fact the barn managers were having 8 year old kids campers feeding breakfast and dinner. In more ways than one, a barn move has been a few months overdue.

And now that super-triple-crazies were stalking my wash stall practices, I began thinking my problems at this barn had multiplied to the level only full-time security guards could handle.

Where has common sense gone!?

Me: Actually, evaporation works to cool the body.”

She argued with me.

As my gaze-of-opposite-amazement grew, I started making a b-line for the car. Safety. I needed safety. I knew I needed to leave, quickly. There was nothing for me to do here.

I tried to give her the benefit of the doubt. I tried to fathom she had read, somewhere, that water was an insulator, PERIOD. But even after that leap, how could one fail to understand the capacity of water insulation and how it relates to a horse being wet?

Factoring in semantics, water IS an insulator of temperature, meaning, water requires high amounts of heat energy to raise said temperature.

However, water being seen as an insulator is a whole different story. How does one not understand the cooling effects of water droplets in relation to heat transfer and the state change from liquid to gas? I assumed this woman must never shower, ever. She must have never seen a coach assailed by his winning team with a bucket of cooled sports drink. She must of never seen a dog shiver in the rain. She must have never visited a desert.

She must not have sweat glands.

One thing is for sure; she must be stopped. She must be stopped from owning or caring for animals. She must be stopped, at least, from ever talking to me again.

Needless to say, I left the barn, completely beside myself.

To anyone else confused about the cooling powers of water, lets talk 3rd grade science.

Water requires high energy/heat for evaporation, and evaporation is inversely related to cooling of ambient temperature. When ambient temperature approaches body temperature, the rate of heat loss slows to the point that very little heat can be removed from the body by any of these means. That’s when evaporation becomes important. Ergo wet horse.

One way to cool a horse in a hurry is to soak a horse with cold water. First, the cold water comes in direct contact with the skin, heat is added to the water by conduction (from body temperature) accomplishing some cooling; a temperature difference of, say 95°F skin temperature relative to 55°F water temperature being the driving force. But more importantly, some water will be evaporated from the skin surface, removing over 1000 BTUs for every pound of water evaporated. Increasing air movement with a fan or wind speeds heat loss from the combination of evaporation and convection.

So, we now understand evaporation does happen when a horse is wet AND evaporation is a cooling mechanism.

Phew – I thought I was totally loosing my mind.

horse spray