Université Paris-Saclay has a strong scientific community of chemists, researchers and students, in an exciting discipline that nevertheless suffers from negative public representation. Chemistry has bad press. "Non-natural", "toxic", "polluting", this discipline carries with it a certain number of stereotypes that stick. The time has come to correct these caricatured representations, which overshadow the variety and richness of the fields covered by research, training and the chemical professions. With the help of daily situations that everyone can identify with, we have decided to defend chemistry and its contribution to major societal issues. (Episode 1/3)
"I do not want chemicals on my plate!"
Yet chemistry is the basis of food! When we eat a food, hundreds of thousands of molecules of amino acids, carbohydrates, proteins, fats, minerals, vitamins and trace elements are ingested. These different nutrients are then recovered by the body, reworked and reassembled to be used as a source of energy, such as sugars, or as components of the human body, such as lipids for cell membranes or amino acids for protein synthesis. Not wanting to eat "chemicals" would be like not wanting to eat!
"Chemistry is not for me, it is too complicated"
On a daily basis, and often without knowing it, everyone does chemistry, thanks to... the kitchen! This ancestral activity is a succession of chemical reactions: we find the reagents (food), the actors of the chemical reaction (temperature, pressure and quantities), and the products of the reaction. For example, to make caramel, table sugar (sucrose) is heated to a certain temperature, with or without water depending on the recipe. In both cases, this results in the degradation of sucrose molecules into two types of molecules, fructose and glucose, which rearrange into long chains of molecules, oligosaccharides, which constitute caramel.
"Natural products are of better quality than chemicals!"
In chemistry, the quality of a substance is essentially defined by the properties conferred by its structure - the sequence of atoms and their arrangement in relation to each other - and is not linked to the origin - natural or synthetic - of the molecule. For example, the vanillin molecule, present in vanilla pods, is responsible for the characteristic vanilla aroma. As the world demand for this flavour is impossible to satisfy through the production of vanilla pods from vanilla plants, vanillin is also synthesized in the laboratory. In the end, as the two molecules have the same arrangement of atoms they give the same aroma.
(Drawings by Elena Vieillard)