How many butterflies crossed the road?

[Patrick Foley]

Martin,

Imagine that time is frozen, and that during that time, you swept down the road
with a net the area of your car's cross section. The volume you swept out (fast
or slow) is constant (=cross section area * distance traveled). You caught 5
butterflies per that volume. You now have an estimate of the butterfly density
per volume at car height.

Imagine you carry a larger net, one the size of the road itself. You now have
another estimate of the butterfly/volume density, 75/volume of the road
(thinking of the road as a tunnel of whatever height you could observe.

You also have a ratio of car cross section to road cross section 5/75.

Patrick
patfoley at csus.edu


cmbb at sk.sympatico.ca wrote:

> Given that I was driving at 75 kilometres an hour for 25 miles as 75 leps
> lept across the road,  how many leps could I estimate to be in that area if
> I knew that it was cropland 25 miles to the east and 20 miles to the west.
> (Yes, I was going in a north/south direction.)
>
> What would I dare to infer over and above the fact that 5 leps now graced
> the front of my vehicle leaving 70 to have continued to fly on somewhere.
>
> Martin Bailey,
>
> cmbb at sk.sympatico.ca
> phone/fax   306 842-8936
>
> 102   1833 Coteau Avenue,
> Weyburn, SK., Canada.
> S4H 2X3
>
>
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