Numeracy: Difference between revisions
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*Ie, a human needs 100w on average | *Ie, a human needs 100w on average | ||
*average crop photosynthesis (conversion of energy to sugar - 1-2%. [http://en.m.wikipedia.org/wiki/Photosynthetic_efficiency]. 7% for sugarcane. | *average crop photosynthesis (conversion of energy to sugar - 1-2%. [http://en.m.wikipedia.org/wiki/Photosynthetic_efficiency]. 7% for sugarcane. | ||
*thus, | *thus, 10 square meters of crop is required per person for 100% energy! theoretical, conservative, assuming the lower photosupynthetic conversion rate. | ||
*Converted to sugars is theoretical. Upon eating, we get | *Converted to sugars is theoretical. Upon eating, we get 40% of food value [http://mb-soft.com/public2/humaneff.html] | ||
*this makes it 225 square feet per person assuming vegetarian diet. | |||
*mowing for conversion to further feedstock (grass for fungi, worms, chickens, fish ) then we essentially multiply the area used, while allowing for operation of a small greenhouse. | |||
=Links= | =Links= | ||
Revision as of 17:03, 19 May 2015
OSE Case
For OSE, numeracy refers to being quick with numbers: understanding magnitudes, orders of magnitude, back of the envelope calculations, basic physics formulas like F=Ma, sizes (like acres and square miles), distances, weights, etc. This refers to working knowledge for quantifying things to one order of magnitude:
- how much power does it take to dual a human?
- How many square miles are there is the USA?
- How many cubic meters of biochar one need to apply 1/4" of biochar per acre?.006 m * 4000 sq m = 24 cubic meters
- How much does a cubic yard of soil weigh?
- How many millimeters of topsoil is lost per acre if the figure is 5 tons per acre?
- How much does one cubic meter of water weight? Of steel? Of rock? Wood?
- Based on a 1% annual growth rate of world population, how many people are born each year?
Specifics
- about 1M calories in a kW hr.
- a human needs 3000 Calories in a day, 2000 if inactive
- note that 1 Calorie (human diet calories) = 1000 calories (pure energy sense calories)
- Ie, a human needs 100w on average
- average crop photosynthesis (conversion of energy to sugar - 1-2%. [1]. 7% for sugarcane.
- thus, 10 square meters of crop is required per person for 100% energy! theoretical, conservative, assuming the lower photosupynthetic conversion rate.
- Converted to sugars is theoretical. Upon eating, we get 40% of food value [2]
- this makes it 225 square feet per person assuming vegetarian diet.
- mowing for conversion to further feedstock (grass for fungi, worms, chickens, fish ) then we essentially multiply the area used, while allowing for operation of a small greenhouse.