Mathematics and bushcraft

[rich59]

Having happily spent ages working out how to assess how far a target is from where I am standing I thought there actually must be loads of maths applications in bushcraft. Some serious and some not so.

So here is a bit about my distance finding:-

How far is that juicy looking mammoth over there so I can accurately sling my atlatl dart at his vital organs?
- I want to creep up to the closest I dare and then sling my dart at the right trajectory. If its 50 paces I won't bother. Is it 30 or 40 paces? Get it wrong and I go over his back or hit the ground in front and he bolts.
- Well, I came up with a number of alternatives. The one I currently favor is to have a "one pace" stick placed on the ground at my throwing point. Then 10 paces back I use a second stick to find two lines from a single point near the beastie that each go though the tips of my "one pace". If I am clever then I can directly read off the distance from said beastie to "one pace" from markings on my 2nd stick.

Then again what are the chances of getting a shot at the mammoth as I busily pace back and forth???

Whats your bushcraft maths?

 

[led]

An interesting idea Rich

I'll plump for the inverse square law and heat radiation (eg a fire). Something roughly like 'for every foot away from the heat source, you halve the amount of heat that reaches you'.

 

[Ed]

There is alot of maths and physics in bushcraft if you want to delve into the science of things....then i would say that as although I teach bushcraft, I'm actually a qualified math and physics teacher (though have only ever taught bushcraft)

Angles play an important part in not only navigation, but also shelter building (60 degree incline to shed water).... even putting up a tarp Body ratio can also help fine tune a bow drill set... there is loads.


Ed

 

[Biddlesby]

Ahh what a brilliant thread. I am off to do pure maths at uni next year.

With a bit of work I'm sure I could mathematically prove that once you've found a particular plant you've been looking for for donkies once, it's not just that you notice more around afterwards, but that more plants spontaneously appear just to mock your previous ignorance.

Actually, I was thinking a while ago about mathematically modelling a bow drill to maximise friction. But then I thought naaah I can't be bothered. See, I'm a proper student already!

 

[Floyd Soul]

With a bit of work I'm sure I could mathematically prove that once you've found a particular plant you've been looking for for donkies once, it's not just that you notice more around afterwards, but that more plants spontaneously appear just to mock your previous ignorance.

QUOTE]

 

[Gailainne]

math students are more likely to work out the best angle for the arm to be at while using an opener on a beer bottle, using the least possible effort. Its -10 degs btw

 

[Ed]

math students are more likely to work out the best angle for the arm to be at while using an opener on a beer bottle, using the least possible effort. Its -10 degs btw

Actually that would be 'applied math' students..... us 'pure math' people only use A's B's C's and a handful of greek letters in our equations


Ed

 

[Floyd Soul]

Ah now lads please don't be bringin back bad memories of school for me!

 

[Stuart]

there are several methods of estimating angles and distance in the bush, some of which are described in the collection of links below

http://www.vendian.org/mncharity/dir3/bodyruler_angle/

http://www.nps.gov/archive/whmi/educate/ortrtg/11or1.htm

http://www.vendian.org/mncharity/dir3/anglecard/

http://www-spof.gsfc.nasa.gov/stargaze/Sparalax.htm

http://www.astrosociety.org/education/publications/tnl/39/sun3.html

 

[Boosh]

The only maths i've learnt so far is that hammock + tarps + knives + all the other toys = empty wallet!

Boosh.

 

[Ed]

Excellent links stuart... nice one


Ed

 

[leon-1]

The first link that stuart mentioned is what the military call hand angles, from what I understand they have been in use a long time.

The military now use mils rather than degrees as this works better with MKA theory (1 mil at 1 Kilometer is equal to 1 meter).

However since stoneage man would not of had the foggiest what a foot, yard, meter or kilometer would of been it's pointless using that as a scale.

It is more likely that he would of used some form of recognition method, whereby he would of recognised that said prey species would of been equal to the height of the joint of one digit (on average) when held at arms length when it was at an optimum distance for him to cast.

Either that or average heights of specific objects could of been used.

The there is the option of numbers + animal driven into corral = animal stoned to death, end equation = lunch.

 

[xylaria]

At the moment I am designing and then making a family size dewelling. I decided on a hemispherical bender. The plans are for a 14 foot wide floor. So r=7ft. Fabric is sold 93 cm or 186 cm widths so how much fabric do I need?

Using (4 pi r squared) /2 I did get to a final answer, but the experiance did make wish I went to school in 1973 rather than being born in 1973. I have only just realised that fabric is being sold in yards, I converted everything to metric then worked it out.

If I was to make a Tipi instead what would the equation be for working out the area of fabric needed?

 

[leon-1]

Not sure on this one xylaria as it is well over 20 years ago.

Area is equal to Pi R squared plus Pi R S where S is slant = square root of radius squared plus slant squared

 

[FGYT]

The first link that stuart mentioned is what the military call hand angles, from what I understand they have been in use a long time.

The military now use mils rather than degrees as this works better with MKA theory (1 mil at 1 Kilometer is equal to 1 meter).

However since stoneage man would not of had the foggiest what a foot, yard, meter or kilometer would of been it's pointless using that as a scale.

It is more likely that he would of used some form of recognition method, whereby he would of recognised that said prey species would of been equal to the height of the joint of one digit (on average) when held at arms length when it was at an optimum distance for him to cast.

Either that or average heights of specific objects could of been used.

The there is the option of numbers + animal driven into corral = animal stoned to death, end equation = lunch.

on finger widths at arms length each finger the sun is above teh horizon is 15mins remaining till sunset so 1 hr for a hand width
cant remember where i found that out but it was a book some years ago

seems to work close enough

if you have a known angle say 45deg you an use it to guage acuratly hights of trees and widths of rivers


duncan

 

[ESpy]

At the moment I am designing and then making a family size dewelling. I decided on a hemispherical bender. The plans are for a 14 foot wide floor. So r=7ft. Fabric is sold 93 cm or 186 cm widths so how much fabric do I need?

Formula for surface area of a sphere is (4/3 pi r^3), so a hemisphere would be half that (!).

Formula for surface area of a cone is (pi r l) where l is slant height.

Of course, fabrics are sold squared...

 

[ESpy]

Cone layout - http://search.sheetmetalworld.com/news/articles/198.cfm

http://www.anvilfire.com/21centbs/math/cones1.htm
Commercial sw with freebie - http://www.pulserate.com/
http://www.red-bag.com/engintools/calccone.php

 

[xylaria]

Formula for surface area of a sphere is (4/3 pi r^3), so a hemisphere would be half that (!).

Formula for surface area of a cone is (pi r l) where l is slant height.

Of course, fabrics are sold squared...

Are you sure 4/3 pi rcubed /2 is not the formula for volume, cause I just come up with 96.7 yrds whereas 4 pi rsquared /2 comes up with 42yrds. I guess-a-mated that I would need about 25 yards of the 2yrds wide fabric. There is really good chance that I am wrong because like most people I can't remember what I did school.

Thanks for for all the stuff on cones, you would believe how useful it is.

 

[sam_acw]

Is there an equation to find how many knives your girlfriend will let you buy? She was ok when I told her I'd only bought one knife. The trouble is I mean to add "so far this week"

 

[ESpy]

Are you sure 4/3 pi rcubed /2 is not the formula for volume

Argh. Teach me to work from memory in random moments... Yes, if you're working with the cube of radius, you're ending up with volume.

Mea culpa, mea culpa, mea maxima culpa.