1 . It’s a warm June afternoon, and in a group of bushes and trees, a bird sings. A small insect climbs over a leaf. The Muziekplein forest, next to an 18-story building and a railway line, is about the size of a basketball court; before it was planted in 2018, the area was a parking place. The forest is one of seven such extremely small forests in the Dutch city of Utrecht, and 144 across the Netherlands. By the end of this year, according to IVN Nature Education, the organization proposing the country’s initiative (计划), there will be 200.

Since the first forest was planted in the Netherlands in 2015, the concept has become popular. Daan Bleichrodt, who launched IVN’s Tiny Forest initiative with the goal of making it easier for children to get into and connect with nature, said that he thinks it is popular because people are becoming more aware of major environmental challenges. It’s a very practical way to do something positive in the light of climate change and loss of biodiversity.

Jeroen Schenkels, a senior adviser for the city of Utrecht on green planning, said he sees the mini-forests as nature-based approaches that are able to help the city weather heat waves and improve water retention (保持). But one of the biggest interests is social. “One of the most important things is that they give people the opportunity to be involved in nature in the neighbourhood,” Schenkels said.

Between 2018 and 2020, 40 different plant and animal groups and 121 total animal species were found in the Muziekplein forest alone. According to Wageningen University researchers, across the 11 tiny forests in their study, volunteers observed 636 animal species. They also identified 298 plant species in addition to the original species planted in the plots. Maintenance(维护) of the forests occasionally involves removing aggressive weeds, but in general new plant species, such as wild flowers that appear, are allowed to grow.

2 . If you live in a region where winter weather is a regular risk, you are likely used to pouring salt on your sidewalks. But how does it work? And how much salt do humans pour onto our planet’s surface? The second question is easier to answer: a lot.

Salt doesn’t directly melt ice, nor does it make snow simply disappear. Instead it makes water less likely to freeze in a phenomenon called freezing point depression. In the case of simple rock salt, which is a rawer, less pure version of table salt, each molecule (分子) splits into smaller elements. Normally, when water freezes into ice, its molecules line up to form a stable, orderly structure. Salt interrupts the process, however, and temperatures must drop lower to overcome that interruption and for freezing to occur.

But if salt needs to interact with liquid water, how does it do anything when temperatures are stubbornly below freezing, and water should already be in the form of ice? That’s where cars help clear their own way by creating friction and, in turn, heat. The friction allows for the ice that has already frozen to melt a little bit, making it unlikely to freeze.

Beyond rock salt’s ability to clear icy streets, it can also be destructive. Chloride ions (氯离子) can cause wear and tear on vehicles and facilities. Increasing chloride densities in North American lakes could begin to upset local ecology and degrade sources of drinking water.

Many local governments are looking for alternatives to rock salt. Other salts such as magnesium chloride and calcium chloride work in the same way as rock salt, and they’re perhaps even more efficient. Some experiments are testing other ice-preventing solutions, including those that contain sugars instead of or in addition to salts. Another approach relies more heavily on sand, which can mechanically make roads safer. All of this experimentation is aimed at ensuring people can travel in any weather condition-a Herculean task when winter brings its worst.

3 . Whether you’re hiking through Yellowstone or camping in the Ozarks, choosing the best backpacking stove (炉子) to take with you can make a big difference. Read on for some of our top picks.

Backpackers love its convenient built-in igniter (点火器), powerful heat output, and four-pronged (四管的) pot stabilizer, which provides a more stable platform for cooking than three-pronged stoves.

The Solo Titan burns twigs, pine cones, leaves, and any other biofuels you may find out in nature, offering a safe and natural alternative to burning gas. The Titan is considered mid-size, ideal for cooking for several people.

Based on hundreds of reviews, hikers say they’re impressed by this gas-powered stove’s easy setup. The Star X2 also features Heat Exchange Technology, which the company says provides superior wind-resistance in different weather environments helping to reduce overall boil time.

Weighing just 2.9 ounces, the Soto Amicus is well known for its light weight and attractive appearance. Multiple Amazon reviewers praise this backpacking stove’s easy setup and four integrated pot stabilizers, which create a stable base for cooking in the wilderness.

4 . It will come as no comfort to a child shivering (打哆嗦) on a playing field on a cold winter’s day. But regular organized school sport helps children in their academic studies in years to come. The researchers said other “structured” activities such as music or religious activities were not as beneficial for attention as taking part in a games lesson. The difference in academic ability was noticeable even at age ten, with those who had taken in sports since the start of junior school performing better than those who hadn’t.

The Canadian study looked at children aged six and then ten. Professor Linda Pagani said, “We worked with information provided by parents and teachers to compare kindergarteners’ activities with their classroom activities as they grew up. By the time they reached the fourth grade, kids who played structured sports were clearly better at following instructions and remaining focused in the classroom. There is something special to the sporting environment — perhaps the sense of belonging to a team to a special group with a common goal — that appears to help kids understand the importance of respecting the rules and honoring responsibilities.”

Researchers began studying 2,694 Canadian children around the age of six, with teachers filled in questionnaires about their behavior in school. Meanwhile, the children’s parents were interviewed by phone or in person about their home life. The exercise was repeated four years later to test what effect the behavior had.

Professor Pagani said, “We found children who had better behavior in the kindergarten class were more likely to be involved in sport by age ten. Nevertheless, we found those children who were specifically involved in team sports at kindergarten scored higher by the time they reached the fourth grade.” The researchers believe sporting activities and attention skills go hand in hand. Professor Pagani added, “The results should be encouraging for schools looking to cut childhood obesity rates and low attainment in schools.”

6 . Perform stand-up comedy

Stand-up is a type of comedy in which someone performs a series of jokes in front of a live audience. Kids can create a stand-up comedy act to perform for family and friends or at a school or community talent show.     1     Here are some tips to help you get started.

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A good first step in stand-up is watching other comedians. With an adult’s help, you can find some kid-friendly comedians on YouTube. (Some family-friendly comedians to check out together might be Jim Gaffigan and Preacher Lawson.) Pay attention to what they do during their routine and what kinds of jokes work.

To begin writing jokes, start brainstorming topics. Many comedians talk about their personal experiences or make humorous observations about popular topics like sports or movies.     3     For example, your friends would probably understand your funny observation about middle school, but your family may not. When you have an idea for a joke, approach it like writing a short essay. It should have a beginning that hooks the listener, followed by a middle that sets up characters or provides information people need to know to understand the joke. Then finish with the point of the joke.

Once you have several jokes written, you can add them to stand-up routine, called a “set”. A set can be anywhere from a few minutes to more than an hour, but for beginners it’s best to keep it short.     4     Between jokes, include transitions to help link one story to the next. You should conclude with a strong “closer”, one last joke that will leave your audience laughing.

Once you’ve created your set, it’s time to practice. You can perform in front of a mirror or record yourself and play it back.     5     Next, perform in front of a friend or family member who can help you see what people laugh at the most or tell you if any of your jokes are confusing. Take notes and make changes as necessary.