This year, the two forms 4A and 4B of the "collège de LASSEUBE" are going to work on a scientific project:

The launching of an atmospheric balloon. We have to select several experiences, create the basket, put those experiences inside it and then collect and analyse the results.

We are going to work with several teachers, particularly with:

- Mrs BARBAZA (technology)

- Mr GOURRAT (physics and biology)

- Mrs GWOZDZ (English)

As well as with Mr Frédéric Bouchar (in charge of "un ballon pour l' école"), scientific organizer from the association PASTEL, and with the collaboration of the CNES from TOULOUSE.

The organizer: Frédéric Bouchar introduces himself, tells us about his job in the association, gives us the instructions and shows us the materials we' re going to use. For example the balloon is made of latex and we' re going to inflate it with helium.

Then we start to calculate the weight a balloon can lift in relation with its volume. We soon realise that it' s time for us to revise our mathematics and our formulas.

In groups, with small balloons inflated with helium, we make experiences, tying up sheets of paper and trying to find the right balance between the weight of the paper and the balloon. Two of the groups are not very talented and we can see their balloons going up towards the ceiling, definitely lost.

After that Frédéric shows us a video concerning this project which was realized in ISTRES, near MARSEILLES with a CM2 form.

After the break, Frédéric and Mr Gourrat explain us and show us the reactions of a balloon inflated with air in a "cloche à vide", and we find similar examples with the packet of crisps or the yoghurt in the mountain.

We' re now going to work in groups on the seven experiences we' ve selected:

temperature

oxygen

luminosity

atmospheric pressure

photo

gravity

humidity

We also talk about the making of the basket and we start our researches.

With Mrs Barbaza and Mr Gourrat, we think about the different experiences we' ve selected, and we work together on our researches (each group explains its theme).

From that point we turn down two experiences: gravity and oxygen. We enrich three experiences: temperature (inside and outside the basket), atmposheric pressure (electronic and mechanical measures). We keep luminosity, humidity and photo.

Finally we draw the functional diagram

We remind ourselves of what we did on November 25th.

Frédéric Bouchar arrives at 9:30 and studies the job we' ve done since his last visit.

We talk about the materials we' ll have to use for our experiences (for example, we mustn' t use mercury, first to protect the environment but also because it solidifies under minus 40°c).

Then we decide the launching day: It will be April 20th. That is to say D Day minus 140.

Frédéric Bouchar presents us the kiwi transmitter and the receiver and explains us their use.

Now in each form, we create groups corresponding to the different experiences and Mrs Barbaza hands out one or two cost schedules ("calendrier des charges") according to the number of pupils in the groups.

We start to elaborate a calendar for each group and on it, we draw the percentage corresponding to the work we' ve done until now and we can see what has still to be done. Then in groups we start researches on the different materials we' re going to use.

One more time we work in groups.

Mrs Barbaza asks us to establish the planning corresponding to each group (what will have to be done each week until the launching day) and also the functional cost schedule.

The groups working on the mechanical experiences stay with Mrs Barbaza,

those working on the electronic experiences go with Mr Gourrat and we start working.

Lecture about balloons made by Mr Tucker from the CNES.

1/ He first tells us about the different areas in the atmosphere: the troposphere, the stratosphere, the mesosphere and explains us why balloons are still in use whereas the first test took place in 1783.

As a matter of fact, it' s the only vessel able to fly in the stratosphere (under the planes and above the satellites) at a very low cost.

2/ He shows us the photos about the first balloons and the first tests which were made

3/ Then he tells us about the different fields of use: aeronomy (the study of the different atmospheric components) astronomy, meteorologie, biology, microgravity (the almost lack of gravity) technology and geophysic (the study of the electric and magnetic fields).

4/ there are different types of balloons

a) expanding balloons (made of latex) what we' re going to use for our project.

b) open stratospheric balloons (they' re used by the CNES and can lift heavy loads [up to 3 tons]).

c) pressurized balloons (their volume is constant and they can fly for two or three months. One of them even flew for a whole year).

d) infrared hot air balloons (inflated with air).

5/ he explains us the different launching techniques (according to the types of balloons),tells us about the aeroclipper, the project he' s working on at the moment, the making of the balloons that is to say the different materials used for the enveloppe and the joining techniques.(He shows us two samples).

6/ at last, he tells us about the G.P.S. (Global Positioning System) and the Argos beacon.

At the end he gives us a very difficult and long calculation.

Each group goes on working on the different experiences until Frédéric Bouchar' s arrival, just before the break.

After the break, each group takes stock of its project and of the work that has still to be done and we start working again.

A journalist from "Sud-Ouest" comes and takes photos of some of the groups being hard at work and asks us different questions. First some technical ones then about the interest we take in this project.

In the afternoon, two other journalists come to see us: one from "l' Eclair" and one from "La République". They also ask us questions about the project and take photos including one of the whole group.

Some groups realize that they have to speed up their work because the launching is always scheduled for Thursday, April 20th and we still have to solve several problems:

-Bad choice of the polystyrene for the basket.

-The syringe.

-The paint.

-The "cloche à vide" is broken.

-The luminosity sensor has been broken during a bad handling.

-the camera (working to be re-examined).

It was a hard and exhausting day for all of us!

All together we take stock of our work and of what we still have to do. Then the groups which have finished their project help the other groups to finish.

Frédéric arrives with the van of the CNES and there' s also Nicolas Fanjeau (he' s from the association PASTEL too).

Frédéric and Nicolas pass in each group, check the work, make comments and give some advices. Some of us still have a few details to adjust (luminosity, releasing of the photo basket and so on...)

In the afternoon, only twenty of us remain and continue with the work, decorate the baskets with Mrs Jammot' s help (our Principal), finish with the camera, make the parachutes, make the last testings with the "cloche à vide".

Finally we clean the classroom.

Mrs Barbaza and Mr Gourrat remain there till 8:00 p.m. to finish the work concerning the luminosity and the releasing system.

The launching is scheduled for 1:30.

With Frédéric, we set up the aerial of the van.

Then, we lay the different experiences on the base plate and the releasing system in the bottom of the main basket and we make tests with the camera basket. Everything is in order but we have to adjust the releasing time.

We test the reception of the data with the aerial and we discover that the electronic pressure sensor doesn' t work because it' s settled too near the KIWI on the base plate.

One group assembles the parachutes with the reflecting echo radars while the other pupils put the base plate with the KIWI and the experiences into the basket.

After lunch, we weigh the main basket and we realize that it' s too heavy.

It' s 1:30 p.m.

General panic!

So we start to lighten it by cutting its lid and hollowing it and also by cutting the four corners of the basket. After long and agonising minutes we finally get the right weight.

Now everything is ready.

We take the different parts of the chain to the middle of the schoolyard under the applause of all the people and parents who' ve come there to attend the launching.

Then Frédéric and Nicolas, helped by some pupils, inflate the balloon with helium. Once the requested volume is reached, Frédéric helps us to tie the flight chain to it.

It' s 2:40 p.m. and at last the balloon is rising under the applause of the ecstatic crowd. Everyone follows it with the eyes and, anxiously, we wait for the camera basket to be released.

As it was planned, it is released and two pupils go and get it on the road not very far from the schoolyard.

Then we rush towards the physics classroom where we wait for the data, communicated every five minutes, from the van, by some of us.

Meanwhile, the balloon continues its flight and finally bursts at 4:44 p.m.

It disappears from the control monitor at 5:05 p.m.

It' s a success!

Our photos have been developped and they' re a success.

The basket has been found in a good state in SARRAMON in Gers ( about 105 kms from LASSEUBE ).