【推荐2】From the roar of a crowd to the quiet of a library, sound and silence might seem like polar opposites. However, according to a new research, our brains perceive them in the same way. Silence may not be a sound, but scientists say we can truly hear it.

In this new study, researchers examined how people experience silence using well-known auditory illusions (错觉). The illusions are meant to test the perception of noise, but for the study, the team adapted them to measure people’s response to silence, instead.

“If you can get the same illusions with silences as you get with sounds, then that may be obvious that we literally hear silence after all.” Chaz Firestone, a co-author of the study and cognitive scientist at Johns Hopkins University, says in a statement.

In the study, participants were tricked by these “silence illusions” in a similar way to how people are typically fooled by the sound versions of the experiments.

The researchers prepared seven experiments and tested them on 1,000 study participants. In one experiment, researchers played a recording that sounded like background noise in a crowded place. In the first half of the recording, the background noise was interrupted by two separate periods of silence. In the second half, one continuous period of silence was inserted (嵌入). Researchers asked participants which silence felt longer- the combination of the first two periods of silence, or the second uninterrupted one. Most participants thought the continuous silence was longer, but it was actually the same length as the two shorter silences combined.

These results were consistent with previous research that examined auditory illusions, which used two separate sounds and one continuous sound. With that illusion, people also perceived the continuous sound as longer than the two separate ones together.

Similar findings across the seven experiments suggested that humans experience silence and sound in much the same way: They can distort (扭曲) our perception of time.

【推荐3】Wildfires are a major source of air pollution. They are also predicted to worsen as climate change progresses.

Within the smoke particles produced by these fires is a wide range of organic chemical compounds known as “brown carbon”. Brown carbon absorbs sunlight, and in doing so, contributes to global warming.

Over time, the brown carbon is bleached by chemical reactions with oxidants (氧化剂) in the atmosphere (such as ozone) and becomes white. This means that it stops absorbing light and stops warming Earth.

This bleaching process is heavily dependent on atmospheric conditions, which vary across regions. The longer it takes for brown carbon to become white, the greater an impact it can have on the environment.

As atmospheric chemists living in a region frequently polluted by wildfire smoke, we wanted to know more about these effects.

Aerosols are microscopic liquid and solid particles (微粒) suspended in the atmosphere. They’re smaller than the width of a human hair, but are still made up of many molecules. Aerosol particles are everywhere and have a large effect on both health and the climate. When aerosol particles interact with light, a portion of the light is absorbed but the rest reflects and scatters off of the particles.

For most types of aerosol particles, the amount of light being absorbed is negligible. That means a lot of the light reflects back to space. Through this mechanism, some of the pollution we create actually masks the full impact of greenhouse gases.

Some aerosol particles, however, are coloured, which means they are absorbing some light. Any light from the sun that is absorbed instead of getting reflected back into space is converted into heat and warms the planet.

Aerosol particles from smoke contain brown carbon. The various molecules that make up brown carbon are similar to some organic dyes (染料), overall giving it a characteristic brown colour. However, when ozone in the atmosphere reacts with brown carbon, it can transform it into new colourless molecules that do not warm the earth.

【推荐1】Sulphur-crested cockatoos (葵花凤头鹦鹉) are common in western Australia, where they normally live in wooded areas. But as forests have been cut down, cockatoos have gotten used to living near people. Scientists report that people in Sydney, Australia are in a battle with these birds.

Last year, scientists at the Max Planck Institute reported that the cockatoos had learned how to open the covers of trash bins. That’s not an easy job. The cockatoos must lift the heavy cover with their beaks (喙) and then walk along, pushing the cover up until it falls over.

When scientists first began studying the cockatoos in 2018, only three areas near Sydney had cover-opening cockatoos. A year and a half later, cockatoos in 44 different areas knew the trick. This time the scientists weren’t just studying cockatoos. They were also studying humans.

The scientists spent weeks studying more than 3,200 trash bins in four different areas of Sydney. They wanted to see how many bins were protected and what methods were used.

In one area, over half the bins were protected. The most common way of protecting the bins was to put a brick or some other heavy objects on the cover. Some people put things like rubber snakes on the top of their bins. The scientists discovered that the humans were teaching each other tricks, too. In most neighborhoods, many people used the same cockatoo-stopping methods as their neighbors.

The researchers say it’s like a race between humans and cockatoos to learn new ways of doing things. Now many cockatoos have learned how to push heavy items off the bins. As a result, humans have figured out ways to attach the items to the top of their bins. The scientists describe the situation as a “human-wildlife conflict”. They expect these conflicts will become more common as humans take over more areas that used to be wild.

【推荐2】The Atlanta-based Coca-Cola company is cooperating with a Danish company to create a 100% recyclable soda bottle.

Plastic is one of the biggest polluters in our environment. And Coca-Cola was named the world's number one plastic polluter in 2020. It is the most frequently littered plastic bottle in 51 out of 55 countries!

While plastic is incredibly useful, it is also unfamiliar to Earth. The bacteria in the soil cannot degrade (降解) plastic back into carbon dioxide and water, because it cannot recognize the molecules (分子) in plastic. This is not the only issue. When plastic eventually does degrade, thanks to the sun, it releases greenhouse gas emissions and harmful chemicals into the environment, only worsening the climate issues already present.

Coca-Cola has finally responded to growing concerns, one of which is to replace the plastic bottle with a paper bottle.

Creating a paper bottle is challenging. The paper bottle must still follow the same safety standards as the plastic bottles. Another issue is the possibility of paper flaking into the liquid.

The first paper bottle will be tested in Hungary this summer. The bottle is made of a single piece of paper-fiber-based material instead of separate parts, which would weaken the bottle. Because paper cannot come into direct contact with the drink, a water-resistant plant-based coating is inside the bottle. There is no clear solution for the paper top yet.

Even if the paper bottles are successful, it will be some time before companies use them to replace cheap and easy-to-produce plastic. Despite this, Coca-Cola's steps towards sustainability are still steps towards a brighter future.

【推荐1】For decades the message to students in the United Slates has been nearly the same: You need to go to college. Students have heard this message loud and clear, ever since their childhood. However, while encouraging students to further their education after high school is a noble and well-intentioned action, the current system in the United States has created some damaging side effects.

The largest and most well-known consequence is the student debt. Tuition and fees at our-year universities have risen by around 54% since 1999. Total student debt in the U.S. is estimated at around $1.6 trillion, so much that even the world’s richest man Jeff Bezos would have to increase his wealth by nearly nine times to pay off all of it.

Although the price of acquiring a bachelor’s degree has gone up, the relative value of having the actual degree has been watered down by the fact that holding a degree is now an expectation, not a bonus. The poor return on investment is also evidenced by the massive waves of students earning degrees in fields where there simply are not enough jobs for the number of graduates, leaving young adults in debt and out of work.

The push for students to go to college has also prevented them from considering careers in important fields that don’t necessarily require a four-year degree, such as construction and manufacturing. Despite the good pay and benefits in these industries, the lack of new blood has lded to growing shortages of both workers and skills，causing delays and higher costs in project like road repairs and infrastructure (基础设施) improvements.

Colleges and universities remain critical to our nation. But as a society, it would benefit us greatly to acknowledge that college isn’t the only form of higher education and career preparation. Students and young adults have more options than they think and informing them of those opportunities can go a long way toward making higher education as a whole more effective, efficient and affordable.

【推荐2】Celebrated educator, author, and motivational speaker Baruti Kafele takes school leaders on a self-reflective journey in his latest publication by asking thirty five focused and intentional questions from one fundamental question “Is my school a better school because I lead it?”, which is also the title of the book.

In this book, which is one of best-selling self-reflection guides, Kafele offers those seeking to improve the quality of instruction in their institutions hard-won wisdom on such matters as guaranteeing a first-rank culture and climate, confirming emergency preparedness, and much more. The book is centered around three key focus areas as you ask yourself the question: your opinion, your evidence, and your staff’s views.

If you’re struggling to transform your practice, improve teacher satisfaction, and—most important of all—encourage students to be superior academically, the book will inspire you. An audio(音频) and text summary of this book is available in the ASCD Leadership Summaries for Educators library. Members can get a softcover at a discount.

About the author

Kafele is not only the author of 12 books, but also the former leader of four urban schools. He wins more than 150 educational, professional, and community awards. One example of his great leadership is Newark Tech, which now wins national recognition. It has developed from being a low-performing one in need of improvement into one that is regarded as excellent.

Book details

Publication Type       Books; Guides—Non-Classroom Use

Product No.       120013

ISBN       978-1-4166-2689-3

Page Count       96