Interesting experiment 1: put the eggs in a bottle and soak them in 0% acetic acid. When the shell of the egg becomes soft, take out the egg, find a jar with a mouth slightly smaller than the egg, put the burning alcohol cotton ball into the jar, and after the flame is extinguished, quickly aim the small head of the egg at the mouth of the jar, and the egg is quickly sucked into the jar. This is because the pressure in the bottle is lower than the external atmospheric pressure. After a while, the eggshell will harden slightly, just like an egg. This principle is explained with reference to the reaction between calcium carbonate and acid. Interesting experiment 2: eggshell characterization Take a red-shelled egg (the eggshell of the red-shelled egg is slightly hard), wash it and gently dry it with a cloth. Take 0 ~ 20 grams of wax, heat it until it melts, dip it in the wax solution with a brush, draw or write on the eggshell, slowly immerse the eggs in 0% acetic acid after the white wax condenses, and stir them with chopsticks to make them contact the solution evenly for about 20 ~ 30 minutes. When there are many bubbles on the surface of the eggshell, it shows that there is obvious corrosion on the eggshell. Take out the eggs, rinse them with clear water and dry them. Punch a hole in each end of the egg with a nail, and blow out the egg white and yolk with your mouth. After all the egg white and protein are dripped out, the white wax coated on the eggshell is scraped off gently with a knife, and finally the eggshell is soaked in hot water, so that obvious patterns or handwriting can be seen. The corroded eggshell surface is easy to be colored. Fun Experiment 3: protein Trace Take an egg, wash off the grease on the surface and dry it. Dip the brush in acetic acid and write on the eggshell. After the acetic acid evaporates, put the eggs into diluted copper sulfate solution and cook them. When the eggs are cooled, peel off the eggshell, leaving clear blue or purple handwriting on the egg white, but leaving no trace on the eggshell. This is because acetic acid can dissolve a small amount of protein after dissolving eggshells. Egg white is a kind of globulin composed of amino acids, which hydrolyzes under weak acidic conditions to produce peptides and other substances. The peptide bonds in these substances are complexed with Cu 2+ and appear blue or purple.