One of my first memories as a child in the 1950s was a discussion I had with my brother in our tiny bedroom in the family house in Bethlehem, Pennsylvania.

    We had heard in school about a planet called Pluto. It was the farthest, coldest, and darkest thing a child could imagine. We guessed how long it would take to die if we stood on the surface of such a frozen place wearing only the clothes we had on. We tried to figure out how much colder Pluto was than Antarctica, or than the coldest day we had ever experienced in Pennsylvania.

    Pluto, which famously was downgraded from a “major planet” to a “dwarf planet”（矮星） in 2006, captured our imagination because it was a mystery that could complete our picture of what it was like at the most remote corners of our solar system.

    Pluto's underdog discovery story is part of what makes it so attractive. Clyde Tombaugh was a Kansas farm boy who built telescopes out of spare auto parts, old farm equipment and self-ground lenses. As an assistant at Lowell Observatory in Flagstaff, Arizona, Tombaugh's task was to search millions of stars for a moving point of light, a planet that the observatory's founder thought existed beyond the orbit of Neptune. On February 18，1930，Tombaugh found it. Pluto was the first planet discovered by an American, and represented a moment of light in the midst of the Great Depression's dark encroachment (入侵).

    Pluto is much more than something that is not a planet. It's a reminder that there are many worlds out there beyond our own and that the sky isn't the limit at all. We don't know what kinds of fantastic variations on a theme nature is capable of making until we get there to look.

Model Railroading

    Would you like to know a fun way to learn about math? Well, you can do that with model railroading. Yes, it's true. You can learn about many school topics without using a school book. Besides that, there are many other benefits that model railroading brings us as well. In this article, we will discuss just a few of those benefits of model railroading.

Patience and problem solving skills

    When you build a model railroad, you have to plan your railroad out. You have to decide where the tracks (轨道) will go, where to put buildings, where to put streets and any other things you would like to add to your model railroad. Also, you have to think about any problems you may have with the design you choose. How will you make railroad crossings? How will you design hills, mountains, and rivers? Deciding on what to do with your model railroad takes a lot of thought and patience, but it is not as difficult as you may think.

Building skills

    With model railroading, you learn how to put together plastic models of buildings. Also, you can learn how to build a table for your design, or make scenery for the geography of your design. Your model railroad runs on electricity, so you learn about electronics as well. These are skills that not only help you build a model railroad; these skills will help you all throughout life.

Fun for family and friends

    Different from many video games, model railroading is a social hobby that lets you communicate with family and friends. This is because you have to communicate with family and friends as you build and run your model railroad. By spending time with the people in your life you love and care about, you learn to become closer and care more for each other. This is one of the best parts of model railroading as a hobby. Of course, the best part about model railroading is running the trains. Watching the trains run around the track and make all the sounds and do all the things that real trains do gives people hours of enjoyment. Also, there is great satisfaction in the fact that you, your family, and your friends built the model railroad.

    I hope you can learn to enjoy model railroading and experience all the benefits you just read about and many others. Happy railroading!

    Amazing concept images have shown what homes of the future could look like, as preparations are made for the world's first free from 3D-printed property (房产).

    Experts will build a house called Curve Appeal, which will be 3D-printed off-site before being put together on-site to create two outside walls, a roof and an inside part. These four main sections will then be joined together.

    Although 3D-printed buildings have been made before, this home - to be constructed in Chattanooga, Tennessee, later this year — will be the first of its kind, as it will contain no regular shapes or angles. The house is the creation of the design company WATG, based in London and California. The design for Curve Appeal draws inspiration from the Case Study House program.

    The architects leading the program were famed for constantly pushing the limits in terms of minimalist (极简主义) materials, and trying to create open-plan spaces that focused on enhancing (增强) natural light. In a written statement, a spokesman for WATG said, “Employing many of the same modem design principles, Curve Appeal is the next evolutionary step. It's important that the architecture and the environment work together harmoniously. The chosen site is steps away from the Tennessee River in a beautiful wooded, sunlit area.”

    WATG was awarded the first prize in the Freeform Home Design Challenge in 2016 and given prize money of $ 8,000 to make its plans a reality. The competition was aimed at architects, designers, engineers and artists. Participants were challenged to design a 600 to 800sq ft single-family home that rethinks traditional aesthetics (美学), ergonomics, construction, building systems and structure.

    Over the last year, WATG's Chicago office has been developing their design with Branch Technology. This project is currently underway, working towards breaking ground later this year. Once completed, the Curve Appeal home will have open and light-filled inside living spaces.

B

    Researchers say they have created a new super-tough material in the laboratory. It is stronger, lighter and costs less than steel. But the new material is not a product of high technology. It is wood. Researcher Liangbing Hu says that it can compete with some of the world's strongest materials or even replace steel.

    The product is called Super Wood. It doesn't require any special raw, unprocessed material. That means the cost of the product will be relatively low.Hu said, “We can start with very cheap wood, and also very fancy, expensive wood. But in the end, we get very similar performance.”

    Super Wood is made by partially removing a natural polymer called lignin（木质素）. Hu explained, “Lignin is like glue to hold all the parts together in natural wood. To be able to densify（增密）the wood completely, some of the lignin has to be removed. “Strong chemicals are put on the wood to remove about half of its lignin. Then, after being left in extreme heat and pressurized for a day, the treated wood is ready.

    The wood is strong enough to build automobiles, airplanes, wind turbines and more. Researchers are finding many new ways to use wood, including creating batteries and see-through wood and paper.Hu said, “Wood has been existing on Earth for more than a million years. And human beings have been using wood for furniture, construction for more than 10 thousand years. And the more we worked on this material, we realized, we have never fully exhausted the potential of this amazing material.”

    In earliest times, men considered lightning to be one of the great mysteries (神秘的事物)of nature. Some ancient peoples believed that lightning and thunder were the weapons (武器) of the gods.

    In reality, lightning is a flow of electricity formed high above the earth. A single flash of lightning 1.6 kilometres long has enough electricity to light one million light bulbs (灯泡).

    The American scientist and statesman, Benjamin Franklin, was the first to show the connection between electricity and lightning in 1752. In the same year he also built the first lightning rod (避雷针). This device (装置物) protects buildings from being damaged by lightning.

    Modern science has discovered that one stroke (闪击) of lightning has a voltage (电压) of more than 15 million volts (伏特). A flash of lightning between a cloud and the earth may be as long as 13 kilometers, and travel at a speed of 30 million meters per second.

    Scientists judge that there are about 2,000 million flashes of lightning per year. Lightning hits the Empire State Building in New York City 30 to 48 times a year. In the United States alone it kills an average (平均数) of one person every day.

    The safest place to be in case of an electrical storm is in a closed car. Outside, one should go to low ground and not get under tress. Also, one should stay out of water and away from metal fences. Inside a house, people should avoid open doorways and windows and not touch wires or metal things.

    With lightning, it is better to be safe than sorry?