For centuries, people wondered how big the Earth was. Unfortunately, although the Earth was flat, no one was able to figure out its size. Gradually, however, people began to realize that the Earth was really round.

    Then, in the third century BC(2,300 years ago), a Greek man named Eratosthenes had an idea. Eratosthenes was sure that the Earth was a sphere. He used the sun and geometry(几何学) to figure out the size of the Earth. He calculated that the circumference(圆周) of the Earth was 28,600 miles(46,000 kilometers). The true size of the Earth is 25,000 miles(40,000 kilometers).

    Eratosthenes' measurement was wrong, but it was very close to the truth.

    For many centuries after Eratoshenes lived, people made maps of the Earth. However, they did not know very much about the world outside of Europe, Asia, and North Africa. Mapmakers could not draw accurate maps of the Earth until people began traveling around the world in the fifteenth century, mapping small areas each time. In the eighteenth and nineteenth centuries, people began making correct maps of countries, but the first accurate maps of the world were not made until the 1890s.

    Maps today are reliable(可依靠的), inexpensive, and easy to understand. People depend on maps every day. What would our lives be like without them?

    The Oklalhoma teen's eyes were covered by two blindfolds（眼罩）. She didn't know she would meet her father, James, after 12-year separation.

    “I had actually discussed with her the night before at a restaurant and talked over the details of where we would go and how we would pull them of,” said Amanda, Rory Beth's mother.

    A video shows Amanda led her blindfolded daughter out of their car and guided her across the parking lot of Broken Arrow Lanes in Broken Arrow.

    Little did she know, her father was on the sidewalk holding a birthday cake that read, “Happy Birthday Rory Beth, Love Dad.” When the teen slowly pulled down her blindfolds, she was extremely surprised. Both the father and daughter stood silently looking at each other until James finally walked over and hugged her. James only broke their embrace to look at his daughter and hold her face. “There were definitely lots of tears from James, myself, and boys, and even a few bystanders,” said Amanda.

    James was a truck driver who spent a lot of time on the road, so Amanda ended the marriage with him when Rory Beth was a baby. “It was hard to figure out how to make it work,” Amanda said. Amanda felt Rory Beth was now old enough to understand and to ask any questions she may have, so the reunion happened.

    The birthday surprise was on June 4, and the father and daughter had seen each other again since, even celebrating Father's Day together. Amanda said her daughter and James were both delighted to be together.

    “She's already calling him 'daddy' and tells him that she loves him.” Amanda said.

    I recently had dinner with someone who told me that one of his best friends had been killed in a private plane crash, and something happened at the memorial service that he'll never forget. He shared the story with me.

    At the memorial service, his friend's wife walked to the platform to speak to the gathering. She said a friend had asked her the best memory she had of their life together. At the moment, she had been too sad to answer, but she had thought about it since and wanted to answer the question.

    They were in their late forties when he died, and she began talking about a time in their life almost twenty years earlier. She had quit her job to obtain her master's degree, and her husband never hesitated in his support.

    He held down his own job and also did the cooking, cleaning, and other housework while she studied for her degree.

    One time they both stayed up all night. She was finishing her paper, and he was preparing for an important business meeting. That morning, she walked out of her study, leaned against the door by the stairs, looked at her husband downstairs and just thought about how much she loved him. She knew how important this meeting was to his future, and she was feeling guilty that she didn't even have time to make his breakfast. He took his briefcase and hurried out. She heard the garage door open and close, but much to her surprise, she heard it open again about thirty seconds later. From above, she watched her husband dash into the house and walk over to the forgotten coffee table. Marking the surface of it with his finger through the dust with the words "I love you", then he raced back to his car.

    The new widow then looked out at her audience and said, "John and I had a wonderful life together. We have been around the world several times. We've had everything money can buy but nothing comes close to that moment."

    Hearing this, I was deeply moved. "Love makes life worthwhile."

    There is a story about a man who lost his legs and left arm in an accident. After the accident, only a finger and thumb on his right hand remained.

    He was a brilliant, creative, and educated man. He had gained a lot of experience while travelling around the world, so he became very depressed after his accident. He was afraid that he would spend the rest of his life suffering and would no longer be able to spend his life in a meaningful way. Then, he realized that he still had partial function of his right hand and could still write even though it was very difficult. An idea occurred to him. “Why not write to other people who need encouragement?”

    He wrote to the prison ministry about sending letters to the prisoners. The prison minister replied, “Writing to the prisoners is acceptable, but your letters will not be answered.”

    Filled with excitement, the man knew he could write his letters. He began sending one way messages of God's love, hope, strength, and encouragement. He wrote twice a week, testing his strength and ability to the limit. He poured his heart and soul into his words and shared his experience, sense of humor, optimism, and faith.

    It was difficult to write those letters, especially without hope of a reply. One day he received a letter from the prison ministry. It was a short note from the officer who monitored and checked the prison mail.

    The letter said, “Please write on the best paper you can afford. Your letters are passed from cell to cell until they literally fall to pieces!”

    No matter what circumstances life may present, we all have unique experiences, abilities, and God given talents. We can discover ways to reach others who desperately need messages of encouragement and strength.

    Play time is in short supply for young children these days and the lifelong consequences for developing children can be more serious than many people realize.

    An article in the most recent issue of the American Journal of Play details not only how much children's play time has declined, but how this lack of play affects emotional development, leading to the rise of anxiety, depression, and problems of attention and self control. “Since about 1955, children's free play has been continually declining, at least partly because adults have applied ever-increasing control over children's activities.” says the author Peter Gray, Ph. D, Professor of Psychology at Boston College.

    We can describe the unstructured freely-chosen play as a testing ground for life. It provides critical life experiences without which young children cannot develop into confident and competent adults. So kids need more of it, not less. Because play is how young children learn important social and emotional skills such as sharing, cooperating, communicating, and empathizing. It helps them develop fit bodies, strong minds, and brave hearts, so they can take on new challenges and risky situations.

    Gray's article is meant to serve as a wake-up call regarding the effects of lost play. We must know that lack of childhood free play time is a huge loss that must be paid attention to for the sake of our children and society. But parents who keep a lookout over and disturb their children's play are a big part of the problem. It is hard to find groups of children outdoors at all, and, if you do find them, they are likely to be wearing school uniforms and following the directions of coaches while their parents dutifully watch and cheer.

    Actually, when children are in charge of their own play, it provides a foundation for their future mental health as older children and adults. Play gives children a chance to find and develop a connection to their own self-identified and self-guided interest. It is through play that children first learn to make decisions, solve problems, improve self-control, and follow rules. Play helps children make friends and learn to get along with each other as equals. Most importantly, play is a source of happiness.

When parents realize the major role that free play can take in the development of emotionally healthy children and adults, they may wish to reassess the priorities ruling their children's lives. The needs for childcare, academic and athletic success and children's safety is important. But perhaps parents can begin to identify small changes——such as openings in the schedule, backing off from quite so many supervised (有监督的) activities, and possibly slightly less keeping watch on the playground that would start the slow returning to the direction of free, imaginative-directed play.

We can create learning moments that students remember forever if we open up our classrooms to awe and wonder. 

Toward the end of my high school year, our Spanish teacher organized a trip to see an Andean band perform in Philadelphia. My classmates and I egged one another on ironically（讽刺地）:Who could enjoy the show? The performers' clothing seemed odd. The instruments, strange. But then the performers kicked in, dancing to their bombo and wancara drums around the stage and the panpipes and quena announced a kind of sound—new to us. 

We had spent too little time discussing the culture of the Inca in social studies but its traditions came alive for us that evening. Once the wonderful performance lit up the stage and the hall filled up with music, my teenage cynicism disappeared. I rose out of my chair to dance with honest joy. 

I have spent the last seven years living and working in South America. But my thirst for cultural exploration and a desire to understand the world outside my language and country has been alive longer than that. Sometimes I think that night dancing to those ancient rhythms unlocked this fascination. Why do I remember it so clearly decades later?

In his recent book Awe: The New Science of Everyday Wonder and How It Can Transform Your Life, psychology professor Dacher Keltner explains that "brief moments of awe are as good for your mind and body as anything you might do." Besides being a memorable emotion, awe boosts curiosity, builds humility, helps with critical thinking, and makes people feel more connected. It even makes us happier. "Twenty years into teaching happiness, "Keltner writes about how to find deep happiness, "I have an answer: FIND AWF."

Moving forward, let's do our best to build instances of awe into our curriculum（课程）. So when our former students approach us on the subway years later, they will recall the magical moments from their days spent in our classes.