Pondering the South African Memesphere – Looking for the Good in Everything header image 2

Evaporation and Temperature

February 15th, 2008 · Posted by Hugo · 8 Comments

Capture if you will, a tropic island
The palm trees wafting gently in the breeze…
(attrib: Flying Pickets)


Consider a body of water. A lake, perhaps.

Water consists of molecules. Each molecule vibrates, with an amount of kinetic energy. All molecules do not have the same amount of kinetic energy, some have more than others. Some molecules are warmer, some molecules are colder. The average kinetic energy of a body of water is called its “temperature”.

The molecules with the most kinetic energy are sometimes able to break free from the body of water. They become water vapour. We say some water evaporates. With fewer high-kinetic energy molecules in the water, the temperature, the average kinetic energy, decreases. The water becomes colder.

The temperature can be stable if the energy placed into the water, by the sun for example, balances the amount of energy lost via evaporating molecules. (I’m neglecting rain and rivers now.)

Now add to the equation some wind. Winds of change. By blowing over the surface of the water, the “warm” molecules are lost more quickly. The sun is still warming the molecules, but before the heat can spread from the warmer to the cooler molecules, the warm molecules evaporate. They leave the body of water. The water cools down much, much faster. Before you know it, what was cool water, becomes freezing cold. Ah, windy days.

Your Swimming Pool

So your swimming pool is too cold to be of much use. You’re welcome to give up on your swimming pool. Fill it with earth. Build something else there instead. Personally, especially when it’s way too hot outside, a swimming pool can be a wonderful place to cool down. A wonderful place to have a party, have some fun together, build social bonds. Play pool games. It is also a great place to train together. Swim laps, get fit, get strong.

Sure, you can go for a run instead, but I like swimming pools. If it is too cold, I prefer to figure out how to get it warmer, instead of simply giving up on it. Many molecules will evaporate, it is stupid to hold it against them. They’re often just too hot for the pool, too alive with kinetic energy, and keen to go explore the atmosphere. However, those warm molecules that stick around and share their warmth with other molecules? They’re wonderful. Noble. They’re the molecules that provide hope for a warmer pool. They’re the molecules that make the swim worthwhile.

At home, our swimming pool can get really warm, because it is painted black. It absorbs energy. (And South Africa is warm, the sun shines. Apparently sunlight peaks at about 1000 watts per square meter, right?) I like black swimming pools. When the wind blows, if we are not too lazy, we roll out that blue “blanket of air”. (What are those called again?) It shields the pool from the wind.

Here’s to warm swimming pools.

Categories: Religion and Science
Tags: · · ·

8 responses so far ↓

  • 1 gloep // Feb 15, 2008 at 6:41 pm

    Ons het so twee of drie of vier (die tyd vlieg) jaar gelede ons swembad “swart gemaak” – was voorheen sulke ou wit teels. Die water is nou wel vinniger warmer in die somer – maar ek sweer dit raak ook vinniger kouer sodra die son verdwyn… ‘n Swembad is op sy lekkerste wanneer die koue re├źn begin stort.

  • 2 Bad Ben // Feb 17, 2008 at 3:29 pm

    Bluxem ja.

    Solar panel are gees kwadraat.

    Warm molecules: cute analogy Hugo. I like it very much. Thanks for the positive input, once again.

  • 3 Bad Ben // Feb 17, 2008 at 3:30 pm


  • 4 Hugo // Feb 17, 2008 at 3:30 pm

    Maybe an over-extended metaphor, but all too often we run away, leaving the pool cooler… just some thoughts bouncing around in my head.

  • 5 Bad Ben // Feb 17, 2008 at 3:55 pm

    jip, totally. We do.

    Semi-related quote:

    “I left the church because I found so little grace there. I came back because I found grace nowhere else.” Philip Yancey

  • 6 Hugo // Feb 17, 2008 at 4:09 pm

    Every time Philip Yancey is mentioned, I think of this piece from his past:

    When Yancey was one year old, his father died after his church elders suggested he go off life support in faith that God would heal him.

    What a load to deal with… Is that what “faith” is about?

  • 7 Hugo // Feb 17, 2008 at 4:15 pm

    blockquote’s cite tag doesn’t seem to render in any interesting way. In this theme, at least. That sentence was borrowed from Wikipedia. Wikipedia cites his bio on Zondervan’s site.

  • 8 Bad Ben // Feb 17, 2008 at 4:42 pm


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