>Research has shown that ants are equipped to sense small temperature gradients and will generally seek an optimum temperature of 24 to 27 Celsius. This means that they should be quite capable of finding an optimum position between stationary or slowly moving standing waves provided that their body temperature does not increase too rapidly when the MW is switched on.<
Non sequitur! Not to confuse the issue with questions of which species of
ants prefer 24-27C (In regions familiar to me, for most of the year some ants
would have to wait for the wee hours of the morning to get such temperatures.
In practice some Ponerine ants go foraging for heat-killed insects in broad
daylight in the sun at temperatures of over 40C. But never mind that!) For a
start, would the relevant stimuli be sensed as differences in temperature or electromagnetic gradients? Would they not be
too fuzzy to orient our ants with the smartness of our own reflexes when we
touch a hot plate? Anyway, who said
anything about “slowly moving”? Why does typical ant motion in the MWO bear no
relation to any plausible nodes? I suspect that they had been neglecting to
take notes in their physics classes.
>What rate of temperature increase could be expected? The dominant energy
absorption mechanism in a microwave oven is the oscillatory rotational action
of the electric field on the polar water molecules. Consequently, for small
objects alongside larger ones, the power absorbed is approximately proportional
to the volume of the item in question. Thermal capacity is also proportional to
volume so the rate of temperature increase should be largely independent of the
size of the object.
If the full 800 watts were absorbed by, say, a 191.4 ml glass of
water, its temperature would rise at a rate of 1 Celsius per second.
A similar rate would apply to an ant or a bacterium or the ant's temperature
sensing organs and is slow enough for an ant to take evasive action by
seeking out nodes in the standing wave pattern. If one considers the ant's
thermal resistance to its surroundings, it may not even need to take evasive
action!<
Not so, but far otherwise…
Take an ordinary plastic drinking straw (well, several actually! But not
dozens.) Preferably go for the teeny, cheap, clear, narrow ones, the narrower
the better, not the great gobjous, vividly coloured, conduits for double-thick
malteds. Seal them at one end. Put water
in each; 1 cm in the first, 4 cm in the next, and so on up to say 12 or 18 cm. If you lay them neatly sloping upwards across the edge of the turntable it should be
unnecessary to seal the other end, but suit yourself. This should total several cc of water, not
several dozen. Put a glass containing 191.40 ml of water at 4C in the centre of
the turntable (or near the edge if you like; I am not Bigoted; I am Jon.)
Turn on the power and see how long you have to wait for the 1 cm column to
warm up, and compare the rate with that of the water in the glass. I predict that no matter how patiently you
seek a node on that turntable, the water in the glass would boil first. Compare its behaviour with that of the longer
straws. I predict that they spurt steam before the glass reaches the temperature of a cup of
tea comfortable to drink.
Any thoughts?
>Thermal resistance is inversely related to surface area and determines
thermal time constant when multiplied by thermal capacity which is proportional
to volume. So it turns out that the thermal time constant of an object is roughly
proportional to its linear dimension. In view of its size and shape, an
ant's thermal time constant should be no more than a few seconds at most.
Simple maths tells us that the temperature rise will quickly
stabilise near a value equal to the product of the thermal time constant
and the initial rate of temperature rise. This means that an initial rate of 1
Celsius per second would result in the ant's temperature stabilising at no more
than a few degrees above ambient.<
But Ped! In your maths, don’t you think it would be amusing to include the
question of how the heat is being fed into the target? And how fast? Where do
you get the 1C/sec??? How, on your assumption do you explain small objects popping instead of stabilising their temperatures?
Hmm?
>Perhaps the ants would initially be attracted to the "hot"
spots in a cold oven, but even in a warm oven they are likely to survive by
seeking refuge at the standing wave nodes.<
How likely? How many ants have you managed to train to stand still in nodes?
And how horrible were the fates of those that went walkabout, fancy free?
Ant marching song: “Ooooooh YE’LL tak the fry node and I’ll tak the froze
node…” sung to the sibilance of spiracles for want of bagpipes, and tattoo of clashing mandibles in lieu of drums. Don’t ask
me what singing ants might use for bugles…
Cheerio!
Jon
