Here is an astonishing and significant fact: Mental work alone can't make us tired. It sounds absurd. But a few years ago, scientists tried to find out how long the human brain could labor without reaching a stage of fatigue(疲劳). To the amazement of these scientists, they discovered that blood passing through the brain, when it is active, shows no fatigue at all! If we took a drop of blood from a day laborer, we could find it full of fatigue toxins(霉素) and fatigue products. But if we took blood from the brain of an Albert Einstein, it would show no fatigue toxins at the end of the day.

    So far as the brain is concerned, it can work as well and swiftly at the end of eight or even twelve hours of efforts as at the beginning. The brain is totally tireless. So what makes us tired?

    Some scientists declare that most of our fatigue comes from our mental and emotional(情感的) attitudes. One of England's most outstanding scientists, J. A. Hadfield, says, “The greater part of the fatigue from which we suffer is of mental origin. In fact, fatigue of purely physical origin is rare.” Dr. Brill, a famous American scientist, goes even further. He declares, “One hundred percent of the fatigue of a sitting worker in good health is due to emotional problems.”

    What kinds of emotions make sitting workers tired? Joy? Satisfaction? No! A feeling of being bored, anger, anxiety, tenseness, worry, a feeling of not being appreciated—those are the emotions that tire sitting workers. Hard work by itself seldom causes fatigue. We get tired because our emotions produce nervousness in the body.

    If you thought pilots dimmed（调暗）the lights before takeoff to give you some shuteye, think again. Believe it or not, the dim lighting could actually help save your life in case of a plane emergency.

    The dimmed lights before taking off the runway and landing are a flight precaution used to help passengers' eyes adjust quicker during an emergency escape. “Going from a brightly lit environment to one that's completely dark would require some time for our eyes to focus and see the escape slide,” Alice Theriault, service director for Air Canada wrote in a press statement. “Since we need to have all the seconds on our side in the event of an emergency, dimming the lights is one of many steps we take to ensure the safety of our customers.”

    The phenomenon that your eyes see those strange speckles (小斑点) as your sight adjusts to a dark place after being in a light place is called dark adaptation. It normally takes our eyes about 20 to 30 minutes to see best in a dark room. The brighter the lights, the longer it takes for our eyes to adjust, which is why dimming the plane lights could shorten your “dark adaptation” time since you haven't been sitting under fluorescent bulbs (荧光灯) all flight.

    Not only does dimming lights add valuable time to the escape process, it reduces the tension on your eyes if you need to look outside, or see the emergency lighting along the passage. “It helps keep you in the right direction.” Patrick Smith, an airline pilot and author of Cockpit Confidential told The Telegraph. “It also makes it easier for flight attendants to assess any outside risks, such as fire or debris, that might affect an escape.” So next time a pilot dims the lights, just know it's for your safety, even though it creates a gentle atmosphere for your takeoff into the sky.

    Long long ago there were a lot of donkeys. The donkeys worked hard every day. They had no time to play or to relax, but they never felt appreciated（得到赏识的）for the work they did.

    One day two donkeys got bored. They wanted to live a comfortable life, so the donkeys went to see a wise old man. They told him their problem. The wise old man agreed they worked too hard, and he wanted to help the donkeys. “I have an idea,” he said.

    “What is your idea?” asked the donkeys.

    “I will paint you and no one will know you are donkeys,” said the man.

    The man went off to find some paint and he returned in just a matter of minutes. He had two pots of paints. One pot was filled with white paint, and the other black paint.

    The old man first painted them white, and then painted stripes（斑纹）over the white paint. When he finished, the donkeys did not look like donkeys at all. “You no longer look like donkeys,” the old man said. “Everyone will be fooled（欺骗）. I will call you something else, zebras（斑马）.”

    The zebras went to a field to eat grass. Now they did not have to work.

    Soon, other donkeys saw the zebras. They asked the zebras where they came from. When the zebras told the donkeys their secret, the donkeys all rushed to see the old man.

    “Please make us into zebras, too,” they pleaded. So the wise old man painted more donkeys. As he did, more and more donkeys came.

    The old man could not paint fast enough. Soon the donkeys became impatient （不耐烦的）. They began to kick about, and they knocked over the paint pots.

    There was no more paint. The painted donkeys ran off to become zebras. The unpainted donkeys, because of their impatience, had to return to work.

    What do Leonardo da Vincii, Marie Curie, and Albert Einstein have in common? They were all left-handed, along with other famous people including Brad Pitt Prince William, and Barack Obama. In fact, an estimated 13 percent of the world's population may be left-handed and still most people around the world are right-handed.

    What makes a person become right-handed rather than left-handed? As yet no one really knows for sure. One simple idea suggests that people normally get right-handedness from their parents. Studies have found that two right-handed parents have only a 9.5 percent chance of having a left-handed child, whereas two left-handed parents have a 26 percent chance of having a left-handed child. Another common theory is that left-handed people suffer mild brain damage during birth, which makes them left-handed. However, if this theory were true, it would not explain why the percentage of left-banded people is so similar in every society, when birth conditions vary so much from society to society.

    Whatever the reasons behind it, people's attitudes toward left-handedness have changed a lot over the years. Statistics show that although 13 percent of young people (10-20 years old) are left-handed, only 6 percent of the elderly are left-handed. Left-handed children used to be punished until they began using their right hand like other children, but today people who are left-handed are no longer looked down on nor are they considered abnormal. For most people today, either case is perfectly acceptable.

    Camping is a good way to spend time along with your kids and to show them how wonderful nature can be. Through camping, children can discover new things about nature, such as flowers, birds, and other small animals. Camping gives kids time to get away from all the electronics (电子) of today's culture. So it is necessary to plan exciting and enjoyable family camping trips with your children while they are young.

    When planning your family camping trip, consider the activities your kids like: games, hiking, swimming, boating, bicycling, etc. Select a camping place that has some of the activities the kids are interested in. Meal planning is an important part of your camping trip. Plan the meals together, and kids love to choose what they want to eat.

    When starting to pack for your trip, let the kids pack their own items (物品) . Each person should have his/her own sleeping bag with a luggage (行李) bag to put it in. Personal items should be packed with their sleeping bags. Encourage the kids to put their items in a certain place and always return it when they have finished using it.

    When you have arrived at your campsite, make all the camping activities a family activity, which will help children to realize how important team-work is. Everyone can have his/her own job sitting up the campsite. Meal time can be a fun time. So let the older ones help with the cooking on your outdoor camping stove while the younger ones get the picnic table ready.

Video calls are a common occurrence, but have you imagined being able to touch the person on the other end of the line? Scientists are making this a reality.

Researchers at the University of New South Wales, Australia, have invented a soft skin stretch device (SSD), a haptic device that can recreate the sense of touch. Haptic technology can mimic the experience of touch by stimulating localized areas of the skin in ways that are similar to what is felt in the real world, through force, vibration or motion.

Vibration is the most common haptic technology today and has been built into many electronic devices, such as one attached to the back of a trackpad in laptops. However, haptic feedback with vibration becomes less sensitive when used continuously. The existing technology also has great difficulty recreating the sense of touch with objects in virtual environments or located remotely.

The new technology overcomes issues with existing haptic devices. The research team introduced a novel method to recreate the sense of touch through soft, artificial "muscles".

It works like this: imagine you call a friend in Australia. You wear a haptic glove with the SSDs and your friend also wears a glove with 3D force sensors. If your friend picks up an object, it will physically press against your friend's fingers. And the glove with 3D force sensors will measure these interactions. The force signals can be sent to your glove so your device will generate the same 3D forces, making you experience the same sense of touch as your friend.

The haptic devices could be used in various fields, allowing users to feel objects inside a virtual world or at a distance. This could be especially beneficial during such times like the COVID-19 pandemic when people rely on video calls to stay connected with loved ones. Or it could be used in medical practices. Doctors can feel a patient's organ tissues without touching them.