Re: Fire (pine knots)


Mario Petrinovich wrote:
deowll:
Actually the myth busters managed to start a fire with a rounded lump of
ice about the size of a person's head. A drop simply won't collect enough
light to do jack.

It would, be sure.

Water drop testing.

Could a monkey or some other animal (Pleistocene Homo for instance)
start a fire by chance simply having sunlight focus through a drop of
water suspended on a hair in the proximity of pitch or some other dry
material?

Glass bottles laying in dry grass have been known to start fires. The
bottom of a coke can polished to a shine with tooth paste can focus
sunlight enough to get a fire started with dry tinder. I've seen
numerous survival-type people start fires with various combinations of
sticks; however, I have yet to see this type of fire started without
first blowing on the hot coal after igniting the tinder material. This
means a combination of wind, water drop held at the correct distance
long enough, along with the right tinder in order for the process to
succeed.

To test the water drop hypothesis, pine pitch has been suggested for
tinder. I happened to have some pine pitch that I gathered for the
purpose of testing its qualities as mastic for attaching arrowheads to
a shaft (it works great).

Materials and methods.

A few of the tools used in this experiment.
http://tinyurl.com/kyx5s


The focal length of the magnifying glass was approximately 7 inches. As
soon as the light was pinpointed on the paper, it burst into smoke
within a few seconds and coals rapidly burnt a hole in the paper.
http://tinyurl.com/hjp8h
Paper with hole burned in it ignited by the 80mm diameter magnifying
glass. Also in the photo is one of the lumps of pine pitch.

Surprisingly, the same method would not light the pitch. It simply
smoked and blistered the pitch as it evaporated, reminding me of the
Wicked Witch of the West in Oz after Dorothy threw a bucket of water on
her.
http://tinyurl.com/ksbsv

No matter how long the glass was applied to the pitch, I could not get
a coal or fire going. I tried several different lumps of pitch just to
make sure the first one wasn't defective in some way.
http://tinyurl.com/g3hd5
A match finally did the trick and reduced the lump of pitch into a
small cinder pile.

Next I tried focusing sunlight through a drop of water suspended on
various items with little success. Gravity seemed to mess up almost
every attempt at some point, mostly wetting the paper rather than
burning it. Using a hair I finally did manage to hold a drop in
place long enough to concentrate sunlight on a piece of paper, but at a
very close distance, something around two or three millimeters focal
length. No smoke could be produced in this manner. Next I tried
focusing the spot of light on my arm. I could feel no warmth at all. If
the ignition point of pitch was higher than paper there was no point in
trying to light the pitch with heat so low I could not detect it on my
arm.

My conclusion is that a drop of water could never kindle a fire using
pitch or anything else, either deliberately or by chance.


It happens every time at the end of dry season in
savanna. You wouldn't imaginr how combustible mediterranean plants are. Once
somebody droped a cigaret while I was in army (I was in Titograd, today
called Podgorica, the capitol of Monte Negro). We went on. Accidently
somebody looked behind. We didn;t go 30 meter, an fire was already 2 meters
high. Thankfully we managed to overcome this.

Was the cigarette lit by a match or a drop of water?


In Podgorica it is incredibly hot. By the seaside it is pleasent,
because sea cools off the air. But inland, where stone reflects the sun, it
goes incredibly hot. -- Mario

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