Introduction
Why do we talk about phosphorus ?
1 of the 9 planetary limits
1 of the 3 planetary limits exceeded
What is phosphorus ?
What is its cycle ?
In which human activities is it used ? How to return to a "normal" situation ?
During the course, think about the different interactions between humans, nature and systems involving phosphorus.
How was phosphorus discovered ?
According to you, how did humans discovered phosphorus ?
A. By looking for the Philosopher's Stone
B. By doing caving (spéléologie)
C. By observing a carp population in a lake
A - Complete answer :
By looking for the Philosopher's Stone AND analyzing urine. Yes.
Who ? Hennig Brand
When ? 1669
Why ? By looking for the Philosopher's Stone
How ? By analyzing large quantities of urine
Properties :
it is phosphorescent
it ignites spontaneously on contact with air
1769 : Scheele discovery
(Gervy, 1970)
(Joseph Wright, 1771)
What is phosphorus ?
According to you, where can we find phosphorus ?
A. In our DNA
B. In our Smartphones
C. In our clothes
(Compound Interest, 2014)
(Sanderson, 2018)
Where is phosphorus ?
(Cordell, 2009)
(Syers, 2011)
(Baturin, 2003)
Why and how humans use phosphorus ?
According to you, why do we use phosphorus ?
A. To create bombs
B. To create fertilizers
C. To create match scrapers (grattoirs pour allumettes)
(Cordell, 2009)
And HOW ?
Use of phosphates before their discovery :
1. Use of bones
2. Use of guano
According to you, what is guano ?
A. A plant that can be smoked
B. A typical Latin American outfit
C. A pile of excrement
Seabirds and bats dropping are full of
phosphorus !
2 reasons to use guano :
Both live in large colonies
High concentration of phosphorus