Lily Pond

version 06
This is a simulation of Exponential Growth and Decay of Population of Lilies in a Pond. Scroll to the bottom of the page for more detailed explanation
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FPS
time
02:D:D_unrounded
LL_c
LL_Z
LL_u
AL_c
AL_Z
AL_u
30
56:34:12
4321
4321
654321
21
4321
654321
21

A Simulation of Exponential Growth and Decay of Population of Lilies in a Pond.

French children are told a story in which they imagine having a pond with water lily leaves floating on the surface. The lily population doubles in size every day and if left unchecked will smother the pond in 30 days, killing all the other living things in the water. Day after day the plant seems small and so it is decided to leave it to grow until it half-covers the pond, before cutting it back. They are then asked on what day half-coverage will occur. This is revealed to be the 29th day, and then there will be just one day to save the pond. Porritt, Jonathan (2005). Capitalism: as if the world matters. London: Earthscan. p. 49. ISBN 1-84407-192-8.

In the face of resource abundance, population, humans included, will grow beyond sustainable level, only to meet the unevitable extinction event. At the beggining, the pond is devoid of Oxygen (a faint blue dot). Overtime, it slowly acculumates to around 700 unit. Oxygen here represents an arbitary resource. A Lily would shrink, unless is absorb Oxygen, which would make it grow in size. After it reaches a certain size, it will reproduce into two smaller lilies. To simulate the infamous J-curve, wait until the pool is saturated with Oxygen, then release just one Lily. The Lily will smother the pond, just like in French story, in roughly 30 seconds. Use the buttons to have more interactions with the simulation. Hover to see tooltips that explains how the button works.

References:


http://en.wikipedia.org/wiki/Exponential_growth#Water_lily
http://demonstrations.wolfram.com/LilyPond/
https://www.youtube.com/watch?v=o0ghHia-M54

Advanced

press F12 (chrome) to open the javascript console and use the guide below to change the constants. Listed below are the constant with the default values.


_CANVAS_WIDTH = 800;
_CANVAS_HEIGHT = 600;
_FPS = 30;
_O2_NORMAL_COUNT = 700;
_O2_REFPLENISHMENT_RATE = 0.0001;
_O2_MASS=107;
_O2_SIZE_FACTOR=0.1;
_O2_COLOR="darkseagreen";
_LILY_AIR_FRICTION_COEF =0.01;
_LILY_COLOR = "green";
_LILY_MAXLIFE = 100;
_LILY_DELTA_LIFE = -0.1;
_AL_COLOR= "brown";
_AL_MAXLIFE = 100;
_AL_DELTA_LIFE = -0.1;
_LLvLL_GRAVITY_RANGE = 4;
_LLvLL_GRAVITY_COEF=4;
_ALvLL_GRAVITY_RANGE = 4;
_ALvLL_GRAVITY_COEF=4;
_TRACE_VALUES_MOD = 30;