全民知識王

The human body is about 70% water, and the principle of microwave heating is to make water molecules vibrate at high speed to generate heat. Therefore, direct exposure to high-intensity microwaves can cause internal tissues to heat up or even burn😱 Everyday use of a microwave is very safe thanks to two strict protective measures: Metal Shielding: The wavelength of microwaves is about 12 cm, while the holes in the metal mesh of the microwave oven's metal walls and glass door are only 1-2 mm. Because the wavelength is much longer than the holes, microwaves cannot penetrate and are trapped inside. Safety Interlock Switch: Multiple safety switches are installed inside. As soon as the oven door is opened, the power is instantly cut off, and the magnetron immediately stops emitting microwaves. It's impossible for it to be 'emitting while the door is open'. Precautions: If the microwave door is deformed, doesn't close properly, or the metal mesh is damaged, microwaves may leak. The eye's lens, being high in water content and lacking blood vessels for heat dissipation, is most susceptible to damage from microwave heating. Therefore, if you notice a damaged or improperly closing door, stop using it immediately and have it repaired or replaced. As long as the exterior is intact, a microwave oven is a very safe appliance.

The invention of the microwave oven originated from an accidental discovery. In 1945, American engineer Percy Spencer was testing a "magnetron," a core component of military radar, when he noticed that a chocolate bar in his pocket had melted. He keenly realized that this might be due to the microwave energy emitted by the radar. To verify his hypothesis, he conducted experiments: first, he placed corn kernels near the magnetron, and they instantly popped into popcorn. Next, he tested an egg, which resulted in the yolk rapidly expanding internally and exploding. These experiments confirmed that microwaves could penetrate food and heat it by causing water molecules to vibrate. In 1947, Raytheon introduced the world's first commercial microwave oven. However, the early models were 1.8 meters tall, weighed 340 kilograms, were expensive, and required a water-cooling system, primarily being used on large ships or in restaurants. It wasn't until the late 1960s, after technological improvements, size reduction, and cost decreases, that the microwave oven truly entered ordinary homes, becoming an indispensable appliance in the modern kitchen. A 1.8-meter microwave oven, why is all I can picture scenes from the movie 'Final Destination' 😱

Primitive Form (5000 BCE - Ancient Egypt): A leather 'loincloth' was found on Ötzi the Iceman from 5000 years ago. Ancient Egyptians used linen wrappings to cover themselves, and nobles wore light robes over them, serving the earliest function of underwear. Middle Ages to Renaissance (5th-16th Century): European knights began wearing linen undergarments for horseback riding; in the 16th century, men even popularized 'codpieces' to flaunt their status. Most women at the time still didn't wear underwear and even held the superstition that underwear was a symbol of impurity. Foundation Period of Popularization (19th Century): The Industrial Revolution boosted the textile industry, and coupled with the rise of hygiene and medical concepts, long drawers to prevent wardrobe malfunctions began to spread among women, and wearing underwear officially became a societal etiquette for everyone. Explosion of Modern Styles (20th Century - Present): 1935: The first briefs were invented, revolutionizing the men's market. 1938/1959: The invention of nylon and synthetic elastic fibers made underwear fit snugly, elastic, and quick-drying. Conclusion: Underwear started as loincloths 5000 years ago, only truly became widespread in the 19th century due to industrialization and increased hygiene awareness, and developed into the styles we are familiar with today in the mid-20th century. It's surprising that underwear has only been common for just over a hundred years. Conversely, not wearing underwear is also a form of revering nature 🤔🤔?

On October 13, 1307, King Philip IV of France, facing financial issues, ordered the arrest of Knights Templar members within France, falsely accusing them of heresy, which ultimately led to their dissolution. (Image: Templar Order's emblem)

• Unique Nose Prints: Just like human fingerprints, the skin pattern on every cat's nose is one-of-a-kind. • Naturally Nearsighted: Cats can only see objects clearly up to about a few meters away, but they possess excellent dynamic vision, night vision, and a wide field of view. • Can't Taste Sweetness: Cats lack the receptors in their genes to taste sweetness. Their interest in sweets is usually due to the aroma of fat or dairy. • Floating Collarbones: A cat's collarbones are very small and not connected to other bones. This makes their shoulders extremely flexible, allowing them to squeeze through any space their head can fit through (practically liquid).

On October 12, 1492, Italian explorer Christopher Columbus, sponsored by the Spanish monarchy, set sail across the Atlantic and reached islands in the Caribbean. This marked the beginning of European colonization of the Americas, fundamentally altering world history. [Playio] On This Day: October 11th https://link.playio.co/p4troai

Elevator Mirrors: Mirrors were initially installed in elevators to alleviate passenger anxiety during rides and to help wheelchair users see their direction of entry/exit when they couldn't turn around.

On October 11, 1962, the Second Vatican Council opened, presided over by Pope John XXIII (Sanctus Ioannes PP. XXIII) in St. Peter's Basilica, Rome. The council initiated modernization reforms for the Catholic Church, including the recognition of the 'Matteo Ricci Rules' and the cessation of the Chinese Rites controversy, which had been debated for over 300 years. [Playio] On This Day: October 10th https://link.playio.co/6g1yyos

Early National Day fireworks were made with signal flares: Starting in 1953, the Ministry of National Defense was responsible for National Day fireworks, and they were even launched using signal flares back then.

On October 10, 1911, revolutionaries launched an uprising in Wuchang, which was echoed by various provinces, ultimately evolving into the Xinhai Revolution that overthrew the Qing Dynasty, ending over two thousand years of imperial rule in China. The Republic of China was declared in Nanjing, and Sun Yat-sen was elected as the provisional president. [Playio] On This Day in History: October 9th https://link.playio.co/evmcyf2