Level 3: Explorers (Age 11–14, Grades 6–8)
Do you want to visit Mars? Someday, you may get a chance. Several countries and companies have plans for crewed missions to Mars. Elon Musk, a famous inventor and founder of the company SpaceX, is planning one of those missions for 2026. But he has even bigger visions. In a 2021 speech, he said that he wants to “build a city on Mars to become a spacefaring civilization, a multi-planet species. ”
“One bug burger, please,” you say. “With lettuce and tomato.” Your meal tastes a lot like a hamburger made from beef. But the patty contains ground up mealworms, which are even more nutritious. The pale green bun was baked with algae instead of flour. And the lettuce and tomato are special varieties created to thrive inside vertical farms. You might be saying “eww” now, but twenty or fifty years from now, you could be saying “yum” instead. In the future, bugs and algae and genetically modified foods might seem normal and delicious, not gross or weird.
When Kea hi Seymour was 12 years old, he watched a television show about kangaroos . He learned that these animals store energy in the long, stretchy tendons attached to their huge feet. Hitting the ground stretches the tendon like a rubber band, storing the energy from the impact. When the animal lifts off, the energy gets released, like a snapping rubber band, giving an extra boost of speed and power.
像鸵鸟一样快——新发明如何由观察自然界而来 Continue reading »
Next time you step outside, take a moment to notice all the plants. You may see a grassy lawn, weeds poking through the sidewalk, towering trees, moss growing on rocks or bricks, or maybe even a vegetable or flower garden. Now let this thought sink in: without plants, you and all the other human beings and animals on this planet couldn’t survive. We depend on plants for the air we breathe. But the relationship goes much deeper than that. We also rely on plants for food, clothing, medicines, materials, and so much more.
Just as you can write the history of the world using the biographies of the famous men and women who changed it (Confucius, Alexander the Great, Queen Elizabeth, Winston Churchill, etc.), you can tell the story of humankind by going from one great cultural center to another. Certain cities at certain moments have defined the course of the arts . Consider Xi’an in the Tang dynasty, Florence and Amsterdam in the Renaissance, London in the time of Shakespeare, or Vienna during the era of Mozart, Haydn, and Beethoven. In exactly this way, Paris during the Jazz Age was one of the most fun and one of the most important cities in the history of art, music, literature, and fashion.
Wild nature seems to be the opposite of a human city. In nature, curvy and messy lines dominate, while in a city, most lines are straight and neat. In nature, the weather changes from rain to heat to cold, while in a city, roofs and heating and cooling systems keep people comfortable. In nature, growth happens chaotically, while in a city, growth is planned and controlled. In a city, people often pave over nature or fence it in. They tame it to the point that it may be hard to notice. But nature is always there. In fact, it is essential.
When you think of a city, you probably think of busy streets and towering skyscrapers . But the city doesn’t just reach up into the sky. It also extends down below the earth. Hidden beneath buildings and roads, a complex network of wires and pipes brings residents electricity, water, and gas and also removes their waste. Underground tunnels house subway systems, storage rooms, or other structures. In many cities, space above ground is so precious and crowded that engineers are finding new, creative ways to use underground space. Singapore is one of those cities. Here, the underground is already used for many purposes, and the city government is looking into ways to build even more underground structures. “You can build up, but there is a limit,” said John Keung when he was CEO of Singapore’s Building and Construction Authority. “The only thing left is to go underground.”
Do you drink sports drinks or energy drinks? As well as being favorite beverages for sportspeople, they are particularly popular refreshments for young people. But do you really know what you are drinking and whether these drinks are doing what they claim to do?
运动饮料和能量饮料管用吗 Continue reading »
Compared to eukaryotic cells, bacteria may seem much smaller and simpler—yet, their way of living provides insights into fundamental metabolic processes that have implications far greater than their size suggests. While the vast majority of bacteria that cluster in the human body are necessary for our existence and survival, certain types of bacteria are disease-causing organisms, or pathogens, and pose a danger to humans due to their ability to infect our cells.
