Image: Shutterstock/Volt Collection
Let’s face it: physics and chemistry are not considered as major subjects for most pupils in lower secondary schools in France. Not so surprising, as pupils are only granted one hour and a half lesson per week from Grade 6 to Grade 9, which is hardly enough to give them a scientific spirit. Furthermore, it is impossible to perform experiments under satisfactory security conditions if the class is not spilt in 2 groups, which has become less the rule, because budgets are currently being reduced. Science really needs to gain consideration.
That’s why teachers in physics and chemistry from all the lower secondary schools nearby my high school (lycée Marguerite Yourcenar in Erstein, France) have decided to organize a competition: a test to be taken at the end of Grade 9 in physics and chemistry and common to all the six lower secondary schools. As a reward the best pupils will participate in a practical session at my “lycée”. Moreover, the 3 best ones from each school will be given a lab coat, which they are going to wear every week during the following year at the practical sessions in chemistry.
So, last Wednesday, on the 17th of June 2015, our laboratories were occupied by pupils younger than usually. My colleague Anne-Laure and I had chosen with care 3 experiments to raise enthusiasm.
In chemistry, pupils were all so happy to look like real scientific researchers, as they had to wear not only a coat, but also goggles and gloves: this was all new for them and they enjoyed it! The experiments were particularly striking:
- The first one had copper react with silver ions to form silver metal: a piece of copper was dipped in a solution of copper sulphate. This chemical reaction is known as “Diana’s tree”, because of the glittery white filaments of crystallised silver that form. Part of the silver also builds up on the rod looking like a dark grey moss. Pupils enjoyed discovering that strange deposit … “Is it also possible to make gold the same way?” was one of their numerous questions.
- The other experiment is called “the magic bottle”. Pupils had to weigh sodium hydroxide and glucose, using specific material such as a weighing boat, a spatula and a funnel. The chemicals had to be dissolved in water in a flat bottom flask. Then, pupils added a few drops of methylene blue: so the solution turned blue. But if you let it rest a while, the colour went lighter and then disappeared completely: this was quite surprising! And then, the solution went blue again when you shook it!!! This was really amazing, it was like … magic!!The blue colour disappeared again, and came back by shaking the mixture. The disappearing and the reappearing of the blue colour can last quite a long time! Of course, some scientific explanations were given to understand what was really going on…
As for physics, pupils could find out the diameter of their hair thanks to the diffraction phenomenon. Diffraction takes place when the light encounters an obstacle or a slit. In this case, the obstacle was one hair. The pattern on the screen is made of several bright spots with dark areas in between. The central spot is the brightest, and its length L can be linked to the size of the hair a. So pupils made measurements to spot a versus L on a spreadsheet. What a fun it was to find out the size of their own hair!
This competition has taken place for 3 years now, and it has been a great success. Pupils that are not interested in science are not eager to participate in such a competition in the first place, but some get caught up in the game. And the winners are so proud to be greeted and congratulated by the headmaster of the lycée where they are going to study the following year, and to perform experiments in real labs! We all think that this kind of events can arouse pupils’ interest and curiosity in Science … We need lots of scientists, so let’s move on!
Artcile written by: Céline Laugel, Scientix Deputy Ambassador