On a cloudless summer day, 13-year-old Charlie Finlayson was ready for a long hike with his father, David.

    Around noon, David was inching his way across a cliff 800 feet above the valley, searching for a line of cracks that would lead them to the top. Charlie stood on a rock a dozen yards to the right as he fed rope to his dad. Reaching up, David missed his step. In the next moment, he heard a sharp crack from above as something larger broke loose.

    When Charlie saw his father sailing through the air alongside the huge rocks that had struck him, he pulled the rope fiercely.

    “Tell me it's OK,” Charlie begged, struggling to control his fear.

    “I think I broke my leg,” David told him. “And we must get off this mountain.” He proposed a plan: Charlie would lower David half a rope length at a time, then lower himself to the same level, and at a new place, begin again.

    As hours passed, they came to the base of the cliff, and David was shaking with cold and exhaustion.

    Worried that David would die if he fell asleep, Charlie kept the conversation going; they talked about past travels. Eventually Charlie allowed himself to catnap, checking on his father each time he awoke. When the sun rose on their camp, Charlie was relieved to see that his father was awake.

    Just after dawn, Charlie headed off on the trail toward the volunteers' cabin 12 miles away, bringing back a helicopter that would carry his father to safety.

    “Charlie's as strong as anyone I know,” says his father, “I'm so proud of him.”

    New York's iconic, blue-green statue of liberty wasn't always green. When the statue was gifted to the US from France in 1885, she was actually a shiny copper color. A new video reveals the chemical reactions involving oxygen and even air pollution that led to her color change from copper to liberty green. The statue of liberty was a gift from France to the US as a way of commemorating the US's fight for independence, as well as their own aspiration for democracy.

    A video, published by the American Chemical Society, explains that the 305-foot (93 meter) statue was built over nine years in sections of copper skin on top of an iron skeleton.

    In her first few decades in the Big Apple, the statue slowly turned from that shiny copper color to a dull brown and the, finally, to the blue-green, or as they'd say back in France, 'verdigris' we see today,' said the video's narrator.

When it changed color, some officials suggested restoring her back to her original color, but after the public protested against this decision, she was left the way she is. The statue's color change was as a result of oxidation reactions between copper and the air. But it was more than one reaction - the color change is due to about 30 years worth of different reactions leading to a mixture of greenish minerals.

    Oxidation reactions happen when an atom loses an electron to another atom.

    In the case of the statue of liberty, her color change was bound to happen due to oxygen in the atmosphere that is 'hungry' for electrons. On top of this, elements of New York City's polluted air added to the color change too.

The first chemical reaction of the color change involved copper giving up electrons to electron-hungry oxygen in the atmosphere. This led to a mineral called cuprite - which is pinkish red.

    Then, cuprite loses even more electrons to oxygen, forming a new mineral（矿物质） called tenorite, which is blackish in color. The black color of tenorite explains why the statue got darker over time, forming a dark brown color.

    Then, further chemical reactions occurred when sulfur（硫） in the atmosphere reacts with oxygen to form sulfur dioxide. Sulfur comes from natural processes such as volcanic eruptions, but also from man-made emissions from boats, cars, airplanes and factories. When sulfur dioxide in the atmosphere reacts with water, it produces sulfuric acid. Sulfuric acid forms green minerals with copper oxides, so the sulfuric acid in the atmosphere made the state green over time.

    Added to that, chloride from the sea spray surrounding Ellis Island where the statue is located made the statue even greener.

    The statue stayed this way for over 100 years because the exposed copper is now oxidized and stable, but the statue wouldn't be the same anywhere else.

    On Saturday my Catalan friend invited me to come along to a Calotada. Being from the UK, I had no idea what this would need, but he promised me it was a fun Catalan(卡塔兰)tradition, and so I agreed to go. I wasn't disappointed!

First, we took a train out to a small town near Tarragona, about an hour away from Barcelona centre. I was already amazed by how different everything looked from the city as the train rushed through small towns, all sitting on the coastline.

When we arrived, we were greeted by the sight of a small wind instrument band and about a dozen people dancing in a circle. While my friend later told me that it is a traditional Catalan dance called La Sardana, at the time I was totally confused at what I was seeing! It seemed so strange but yet so lovely that they were doing this dance completely for themselves.

Once we had been fully entertained by the dancers, we finally went inside for the Calotada and it was soon revealed to me what it actually was. We sat down at the table and a huge plate of leeks(大葱)was placed in front of us. It was explained to us that you have to peel the leeks with your fingers, dip them in a (delicious!) sauce and eat them. This sounds easier than it was.

    My friend had been right in the end, it had been an extremely fun day and it felt great to get involved in a local tradition of a place I am temporarily calling home. It really inspired me to learn more about the Catalan culture, although hopefully next time it will be something less messy!

    A new report says living in a city makes it harder for people to concentrate(集中) on some tasks. The research found that people who live in rural areas can focus better than people in urban areas. The study is from Goldsmiths College, which is part of the University of London. Head researcher Dr. Karina Linnell and her team made great contributions. They studied how two groups of people did the same "thinking tasks". The team went to a remote(偏远的) part of Namibia, southwest Africa, to study the Himba tribe. Himba people live a very basic life in the desert. They are still doing traditional farming. The team also studied members of the same tribe who had moved to the nearest town. Dr. Linnell said the tribe who lived in the desert did much better on the tests than those in the town. It's really interesting and shocking.

    Dr. Linnell said their research may lead to changes in the way companies operate. In the future, workers may move from cities to live and work in the countryside. Linnell said there are too many things around us in the city that stop us from thinking about one thing for a long time. This means we do not work at our best. She asked, "What if, for example, companies realized certain tasks would be better carried out by employees based outside of the urban environment? There their concentration ability is better. "The past century has seen billions of people move from the countryside to big cities. In the future, the trend may not continue. If Dr. Linnell's research is true, this century might see many of those people return to the great outdoors. Let's wait to see what will happen.

    When I got home after dropping out of college in my junior year because of depression, I didn't want to get out of bed. But my parents wanted me to, so I just transferred myself to the couch in the living room. Sometimes I would turn on the TV and watch marathons of Chopped, but mostly I just sat there, lost in thought.

    One day when I was lying on the couch, not knowing what to do, I wondered since I had been out of school for a long time, I might as well do something productive with my life. I looked at my options. I could attend some kind of online college class, go to in-person events just to get out of the house, or take up a hobby. But none of these things made me happy, and my depression seemed to keep me drowning under the waves.

    There was something that was my thing—entrepreneurship. No matter what kind of day I'm having now, the mere mention of start-ups still perks me up. I have been starting business in some kinds of forms ever since I was a kid, and despite everything, this passion has never changed.

    So I started thinking of ideas, seeing which one could become practical business. I spent my days glued to a wide purple notebook, a pen in hand, sometimes moving from the couch to the table on our back porch in the mornings. If I got up early enough, I'd watch the sun come up. It was there, in the still mornings, that I learned about life and started to look back on mine.

    With time going on, the depression started to lift. I was making more progress in my recovery, and the good days were more frequent than the bad. I started a couple of different businesses, eventually settling on a web design business, and did a lot of experiments and changed my ideas, and after a while, things started to work.

    I am afraid of heights but two summers ago I climbed to a high place. Most of our high school had come along on a day trip to a beautiful beach village in Peru. After eating our lunches, many of us wanted to make the climb to an area around the village.

    Do I turn back? "Yes!" Will I regret (后悔))it later? I really want to get to the top, but... At last, I decided at least to have a try.

    My friend Tom was in front of me. Then, suddenly, he slipped (滑倒))and was about 10 feet back! My heart was beating faster until he stopped himself. Knowing that my friend Seth would be right behind me, I began the climb. I was soon past the first challenge safely, but not feeling much better about the rest of the climb. Looking down, I saw rocks everywhere. My breathing sped up, and my heart beat even faster, growing loud in my ears.

    My friends kept climbing. But they did not forget me. Someone was always behind me to help hold my feet when necessary, and someone else was always in front to offer a hand up. With friends helping me by words and actions, I slowly gained ground.

    Then we came to the worst part. The climb looked very close to vertical (垂直的). To me, the wise choice was to go back down. Melody encouraged me to go on and she made it safely first. I stopped, unsure of my footing. "You can do it, Jean! I'm right here," Melody called. She waited patiently, not asking me to hurry. I took a few deep breaths and kept climbing.

    With no more mistakes, we came to the top finally. I was dirty and tired. But it didn't matter. I was at the top! I had never felt so alive.