Penicillin: When Xia Fleming was on vacation on 1928, he forgot that bacteria were growing in Petri dishes in the laboratory. Three weeks later, when he returned to the laboratory, he noticed a group of turquoise molds growing in a staphylococcus aureus Petri dish that was accidentally exposed to the air. Microscopically, the staphylococcus colonies around the mold have dissolved. This means that some secretions of mold can inhibit staphylococcus. Subsequent identification showed that the above mold was Penicillium punctatum, so Fleming called its antibacterial substance penicillin.

Preparation method of graphene: Heim and team members stumbled upon a simple and easy new method to prepare graphene. They put the graphite sheet in plastic tape, folded the tape on both sides of the graphite sheet, tore the tape, and the graphite sheet split in half. By repeating this process, thinner and thinner graphite flakes can be obtained, and some samples consist of only one layer of carbon atoms-they have already made graphene.

Steam engine: Watt accidentally discovered the principle that the kettle lid vibrates when water is heated, which provided a factual basis for his later invention of the steam engine.

Gravity: When Newton was resting under a tree, an apple fell on his head and he discovered the law of gravity.

Continental drift: When Wei Gena was ill, he happened to see a prominent part of South America on the world map just corresponding to the Gulf of Guinea in Africa. Then he found that every concave and convex part of South America had a corresponding part in Africa, so he came up with the theory of continental drift.

Vortex direction: Professor Xie Piluo, head of the Department of Mechanical Engineering at MIT, found that the vortex of water always turns left, that is, counterclockwise, which is associated with the rotation of the earth. It is judged that the counterclockwise rotation of typhoon in the northern hemisphere is the same as the vortex of bath water, while the clockwise rotation in the southern hemisphere is just the opposite, which will not form a vortex at the equator.

Eye movement: An Austrian doctor happened to find his son's eyes moving while he was sleeping. He woke up his son. His son said that he had just had a dream, and then he observed a lot, and the answers were the same. Then he wrote a paper saying: When the sleeper's eyes turn, it means he is dreaming.

Gunpowder: The alchemist accidentally burns honey (which turns into charcoal when heated), saltpeter and sulfur together, and then ... everyone knows what will happen.