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ddiissccoovveeyyrrXXBBHISTORY SCIENCE WORLD NATURE
DOCEXPERIMENTddiissccoovveeyyrrXXBBDiscoveryBox Labs
ANIMAL QUESTION
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An artificial legThis prosthesis replaces a limb that has been lost, often after an accident. It allows the user to walk and move thanks to a tiny integrated computer. Since it is very lightweight, it can also be worn for sports. There are also prostheses for hands, hearts, and even eyes!
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IN 1870 AND 1871, FRANCE GOES TO WAR* AGAINST PRUSSIA. THEN A REVOLUTION BREAKS OUT IN PARIS. MADELEINE, STILL A STUDENT, WORKS IN A HOSPITAL AS MANY DOCTORS HAVE LEFT TO FIGHT.
Why does food rot?Sometimes food will go horribly bad.You’ve probably noticed this before. Do this experiment to learn why!You will need: ⬤ a slice of bread ⬤ two soup dishes ⬤ cling film ⬤ water4 Pour a little water on one of the halves.1 Cut the slice of bread in half.2 Place each half in a soup dish.5 Cover the wet half with cling film. Then leave the two dishes side by side.3 Leave the dishes outside for a day.EXPERIMENT40
Do you know how to store foods?Turn the page to find out…The cling film kept this piece moist.Without cling film, this piece has dried completely in the open air.WHAT HAPPENED? The added water and cling film kept the bread from drying up. Additionally, mould from the air settled on the wet bread. The moist environment was perfect for the mould to grow. Meanwhile, the bread in the open air was too dry for the mould to grow quickly.Spots appear on the wet bread. It even begins to rot. This bread can’t be eaten. The other piece of bread hasn’t rotted.A few dayslater...Mould and other microbes can grow in your food. They are generally toxic and bad for your health. This is how many foods end up rotting and becoming dangerous for health.Air carries microscopic mould cells called spores.The velvety substance on the bread’s surface is a type of fungus. This is mould.41
Food can also be protected by processing it in salt which dries it.Before freezers existed, this was the only way to store food for several months. Cold temperatureskeep food fresh for several days as they slow down the development of microbes. Frozen food can keep for a very long time. But beware, freezing doesn’t kill the microbes which will wake up when the food thaws.Packaging with all the air sucked outis known as “vacuum packaging”. It keeps food fresh longer because microbes also need air to live and grow.And of course, there are dry foods…These do not contain enough water to let microbes grow so these foods can keep for a very long time!To keep microbes from growing on our food...Covering food as quickly as possible can prevent microbes from falling into it.42© Bayard Presse - ImagesDoc No.387 (2021) - Text: Erik Franck; Illustrations: Jérome Sié and Mathilde Courtès; Photos: © Rebecca Josset; Special thanks to Annaëlle for participating.
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