Home > Clement's Game > Fantasy Round 40: Zahrah the Windseeker

Fantasy Round 40: Zahrah the Windseeker

Zahrah the Windseeker really exists in a strange land in between science fiction, fantasy, and myth, so I’m not completely confident in my assignment of genre.

Nonetheless, the book is a light, pleasant read in a fascinating world.  If you’re looking for a bit of a break from gritty dystopias (like I was), this novel is a good choice.  I actually will be avoiding most of the spoilers, so… read away.

Appropriately, Zahra is on the cover. I'm not sure why there's a butterfly.

Appropriately, Zahrah is on the cover. I’m not sure why there’s a butterfly.

How Does That Computer Work, Anyway?

Zahrah’s country is powered by literally home-grown biotech.  Special flies are used to deliver injections, buildings are grown from the ground up, light bulbs are plant-produced, and computers are grown from CPU seeds.  There is also a biological talking compass, with an attitude.

The computer Zahrah has is described as being one that she has grown herself from a seed, and which grows with her as she grows up.  At one point, it is described as using the warmth of her body as a power source.

But is that likely to work?

Googling the Internet suggests a typical laptop power usage of between 20 and 100 watts, depending on things like the size of the screen and whether the battery is charging or not.

On the other side of the equation, Wikipedia has a nice article about human-powered things — but it focuses on sources of mechanical energy, like pedalling a bike, rather than simple waste heat.  Further, it reports an estimate that a healthy adult on a stationary bicycle can only sustain 50-150 W for about an hour.  Now, that’s how much energy is in the motion of the pedals, and not all the waste heat coming off of the active cyclist.  Humans are not terribly efficient generators.  (According to another Wikipedia article, at least half the energy from the glucose your body processes goes directly into heat.)

Finally, there’s another issue — the limitations of thermodynamic efficiency.  How much of that waste heat is actually usable depends on the temperature difference between Zahrah and the room.  To get an idea of the maximum possible efficiency, let’s use typical human body temperature for Zahrah, 37˚C.  (Her skin will actually be cooler than that, but the core temperature is a useful starting point.)  Room temperature is typically about 23˚C (or around 73˚F).  The efficiency we want is given by (T_high – T_low / T_high), where all the temperatures are in Kelvin.  (Or you could use Rankine, but… nobody uses Rankine.)  With that conversion, we get a maximum possible efficiency of about 4.5%.

Even if Zahrah just came back from running around the block, and was giving off 100 W of energy (and likely less, if she’s sitting still and not exerting herself), and was entirely wrapped in a suit to collect all that heat and funnel it into her laptop, the laptop could still only take in about 4.5 W at most.

And that’s not even accounting for the fact that the computer is, well, only in contact with her lap, and likely to be less than perfectly efficient at converting heat into useful power.

In short, while the idea is pretty nifty, it’s only going to work if either the laptop gets a lot of power from other sources (solar, perhaps), or if it’s far more energy efficient than modern hardware.

The Forbidden Forest

While the forbidden nature of the Forbidden Greeny Jungle is critical to the story, the deliberate closed-mindedness and outright superstition of the adults is annoying.  Admittedly, the forest is dangerous, especially for the unprepared, and that kind of cultural inertia is not unprecedented — far more terrifying things have been advocated by real societies, and since it has some basis in fact, I can see it happening.

More serious is the fact that the adults — as in many stories, and, alas, real life — are horrible at preventing Zahrah from being bullied.  And, sometimes, don’t even realize what’s going on.  Why don’t the adults do something??  The adults themselves may be uncomfortable around Zahrah’s differences… which is an explanation for their behavior, but no excuse.  Arg.

The Adults Are Useless is a core component of many stories intended for youth, but it’s still very frustrating.

Less the incompetence of the adults, the forest is beautifully described.  The guide book is amazing (and not always quite correct), and the forest itself has a mystical, fairy-tale like quality, from the mysterious pink spotted frog to the great panthers who politely discuss whether they should eat the protagonist.

All in all, it is a tale well told.

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