how to prove its presence in french ... - académie de guyane

The dust of sahara.

How to prove its presence in french guiana ?

Problematic

French guiana is victim of a dust wind fromEast.It's probably the dust from Sahara.This phenomenon reduces the air quality in french guiana

4) We recover the dust or the sand in the mirrors withthe same scotch but never in the same place .

5) For the first day we recover every 3 hours and afterwe recover the dust and the sand once a day .

6) We place the scotch recovered in labels with hisdescriptive

Goals of project

We have several goals in this project :

- Study the dust in polarizing microscope

- Observe changes abundances

- The air quality

The 9 of october 2015

Meteorological photography.

Some solutions to collect dust .

Hypothesis :Hypothesis :

● We can put white wet cover on windows torecupere and identify if it's dust or sand.

● Used scotch tape on glasses or mirrors

Differences between the polarizingmicroscope and the Scanning

Electron Microscope

A light polarized

A photon has a magnetic component and an electricalcomponent. When we observe a light source as a bulbwe notices that the orientation of the electric field iscompletely random of a photon has another one, it iswhat we call of the light not polarized, because it doesnot present privileged orientation.

By placing a polarizer in front of the source, we sort outphotons following the orientation of their electric field, Atthe exit of a polarizer all the photons have their electricfield directed in the same way and that's what we callpolarized light.

Scanning Electron Microscope

The polarizing microscope

Compare the dust of sahara observed betweenpolarizing microscope and the scanning

electron microscope.

scanning electron microscope

polarizing microscope

Differentiate sand of beach, dustof path and dust of career.

With the same scotch we have recovered sand ofbeach, dust of path, dust of career and we have

observed these in a polarizing microscope

dust of career dust of path sand of beach

We have choose the scotch solution :

On a clean glass we recovered with thescotch at precise hours the dust presenton our mirrors for a week and next we

observe these dust in polarizingmicroscope .

Protocol :We want take sand of beach and dust of a

career, Ludivine lives next to the beach andRomane next to a career :

1) We clean mirrors with a product for glasses

3) We search a place for these mirrors

3) we place the mirrors in the same angle

4) We recover the dust or the sand in the mirrors withthe same scotch but never in the same place .

5) For the first day we recover every 3 hours and afterwe recover the dust and the sand once a day .

6) We place the scotch recovered in labels with hisdescriptive

Dust of career Sand of beach

After 3hours

12 hours

24 hours

Dust of career Sand of beach

2 days

3 days

4 days

5 days

Conclusion :

We can observe in first time that after five daysthere is enough of sand or dust to analyzethese in polarising microscope and in secondtime we can see in the microscope thedifference of the sand of beach and the dust ofcareer : the sand of beach is thicker than thedust of a career . .we can deduce that anywhere you live inGuyana , the air is full of dust or sand.

Thank's for listening !

Ludivine SIMON

Romane LAZZARO

Elmer DOS SANTOS DA SILVA