Tonight,
I was offered a stage in a theater,
700 pairs of ears,
and I was asked to inspire.
(Laughter)
I said to myself :
” Why not ? It would be an opportunity to leave my research laboratory,
to rub shoulders with humans again
and to see the light of day. “
(Laughter)
That’s how I decided to tell you my story,
to help you better understand
the impact of science on the environment.
The story began seven years ago,
I was still in high school
about to choose a scientific branch,
when my math teacher came to tell me:
“Yousra,
change of sector,
the sciences are too complicated for you. “
It hurt!
(Laughter)
But as I’m a little stubborn, I decided to do exactly the opposite,
and leave an impact on the scientific world.
(Applause)
This did not prevent me from asking myself a few questions.
And from memory, what had the most questioned me,
it was: “Why is science so scared? “
Two hypotheses came to mind.
The first is pretty obvious;
it comes from the fact that we humans,
we tend to choose the simplest phenomena
and give them the most complicated words.
This has contributed to the removal of many of us from the scientific world.
The second hypothesis is a little less obvious
and requires a little deeper reflection.
Science, basically, it was made to observe the environment,
predict his behavior,
to ensure the survival of our species.
But over the centuries,
we have moved farther and farther from that goal
and we went from a constructive goal
to a destructive purpose.
We combined science and industry,
we have developed more or less polluting sciences,
we started to eat,
overeating,
but we did enough harm to this planet
which has so welcomed us so far.
Before starting my engineering training,
when I was told about materials,
science,
the only thing I could think of was this –
(Laughter)
but as and when
that I learned a little more about the world of materials,
I realized that they are not very different from us humans.
In the realm of metals, for example,
we will find different social classes.
At the top of the pyramid, we will find the most noble metals;
they have an easy life: they pay a lot to have them.
And as we go down in the pyramid,
the potential will decrease more and more
and at the base we will find the least noble metals,
like titanium, magnesium, zinc, etc.
Metals can also have a character trait.
We will find, for example, the capricious,
like semiconductors,
who will let the current flow in one direction,
but not in the other.
We will find the fragile ones, like ceramics,
that will break in a thousand pieces from the first shock.
We will also find the devoted ones,
like zinc
that we will use in sacrificial rings,
to protect steels against corrosion.
Who says different character traits
also says different social behaviors.
When we are going to contact two metals, for example,
different things can happen.
For short, I will take two extreme examples:
either they will have a repulsive behavior,
like what will happen when we have two magnets with the same pole,
either they will have an attractive behavior,
that is to say, they will attract each other to the point of diffusing one into the other.
This is what will allow us to make assemblies.
Now, what happens at the atomic level,
it is this:
we will imagine a material A,
and a second material that will be called material B.
You see the yellow atom in the middle,
– the handsome kid with glasses –
(Laughter)
he’s going to realize that the neighboring atom is not that bad,
(Laughter)
and they will decide to get together,
when conditions permit.
By conditions, I mean
high temperature, the presence of moisture,
the passage of a current, for example.
(Laughter)
And they will decide to settle in the neighborhoods of Madam,
because she is nobler perhaps,
that his neighborhood is nicer.
Except that, when Monsieur will move,
he will leave a void.
Now imagine that several pairs of atoms are formed.
Well,
several voids will form,
and the void will accumulate,
to the point of appearing on the macroscopic scale.
Concretely, the material will deteriorate,
will disintegrate.
As a scientist,
we will play the role of border agent,
that is to say, we will try to regulate the passage of atoms.
We want to make a deposit.
So,
it does not matter if material B deteriorates.
So, we will maximize the flow in one direction.
Either we will play the role of the villain,
we know that atoms love each other well,
but we will still separate them,
because it can be dangerous for the structure.
Either we will be reasonable,
and we will balance the flow in one direction as in the other.
And that’s what we will use to make assemblies,
among others, in electronics.
Now, in my case,
material A is copper,
material B is tin.
My problem is that pewter is not that beautiful.
(Laughter)
And suddenly, Ms. Copper does not want to get along with him.
(Laughter)
So, what we do, we will try to cheat.
We will put on her glasses, a bow tie,
(Laughter)
we’re going to add perfume to her, and all that.
(Laughter)
And concretely, it’s about adding lead.
Currently, it works well.
We manage to make assemblies thanks to that.
We manage to lure Madame Copper.
On the other hand,
lead is a heavy metal.
It’s a heavy metal,
and that’s what will do that part of your computer,
part of your phone,
– where there will be a presence of lead –
will not be recyclable.
And who says non recyclable says:
accumulation of waste and in particular electronic waste.
We are talking about three million tonnes of electronic waste in 2020,
the equivalent of 297 Eiffel Towers,
and 57 Titanic.
Now, we understand that it’s not good to cheat,
we will do with what we have.
We’ll just make sure
the first meeting between Madame Copper and Monsieur Étain
be the most unforgettable possible.
(Laughter)
That is to say we will do so
that the atmosphere is warm,
the temperature will be raised to 300 ° C.
(Laughter)
We’ll do a little wind of acid
and we will plunge them into the void from time to time
until the passage of the atoms is balanced,
in one direction as in the other.
Then,
the pairs of atoms are formed,
will give birth to a first generation of atoms,
we will call Cu6Sn5,
then to a second generation of atoms,
Cu 3 Sn.
And they are robust,
they have better properties than their parents,
and therefore allow to ensure an assembly that is the most robust possible.
Now, if I told you all that,
it is especially to draw your attention to the efforts
which are provided on a scientific scale,
to overcome the mistakes of the past.
I know that a lot of you –
let’s say the majority, otherwise it would not be human –
we are all upset that in the world,
we use nuclear weapons, chemical weapons.
But we forget that each of us holds an equally destructive weapon,
which is our way of consuming.
(Applause)
What I would like you to do when you leave this room,
that the next time you try to make a new acquisition,
imagine the whole process.
Imagine that you have to separate each material separately.
Imagine small boxes in which we will put these materials.
Each small box is intended for a given way of recycling,
more or less complex.
And keep in mind that somewhere,
there is a part that will not be recycled.
Because if we continue at this rate,
we will have all the gadgets of which we dream,
but we will not have a planet to live on.
Thank you.
(Applause)
”
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