Sometimes it can be easy to become too satisfied when it comes to living sustainably. We may all have recycling bins in our kitchens, but here are some ways you can live more sustainably.

    ⒈Put an end to plastic water bottles and one-off coffee cups

    The only way this is going to work is that if you have reusable options you really love, invest in a great water bottle. This is an advance payment, but it will save you money in the long run. A 750ml bottle of Evian costs 90p in Tesco, meaning if you buy one every two days you could save £10 within three weeks by filling up a reusable bottle at home.

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    The high street is problematic on so many different levels. Not only are you buying items with questionable supply chains, but the carbon footprint of each product is shocking as well. Online shopping is even worse, with overpackaging for each item and the emissions from delivery trucks. The answer is to stick to reach-me-down or previously owned items as much as possible. Not only will this save you money, but there's also a sense of satisfaction in finding a hidden treasure from the flea market where you find outstanding bargains or something used, which you simply can't get from shopping in Wal-Mart or on Amazon.

    ⒊Think hard about your transportation

    Even if your car is supposedly a low-emissions model, it's still going to be a huge contribution to your carbon footprint. There are times when getting in a car can't be avoided, but if you can substitute just one flight a year with a train, one car journey a week with a bus, and one bus a month with a bike ride, you'll find that making more mindful transport decisions can easily make your day-to-day life more environmentally friendly with little effort.

    ⒋Try to buy local, seasonal produce

    You may think buying strawberries in December or courgettes in spring is no big deal, but the chemicals and fuel used to artificially copy the right environment for them to grow create harmful gas emissions. Similarly, the environmental impact of transporting produce from another country is huge. Buying from local farmers also means you can often ignore the huge amounts of packaging the supermarkets use.

    “An apple a day keeps the doctor away.” Similarly, if we drink a little more water every day, we may find that we need to go to the doctor a lot less often. A healthy diet is made up of water and a great many different kinds of foods. We know that healthy foods like fruits, vegetables and fish, are important as they provide us with energy and fiber, without giving us too much fat and sugar. But why is water important?

    The human body needs water to survive. Water is important as it carries poisons and waste out of our bodies. However, doctors advise us to drink plenty of water, much more than the small amount we need to stay alive.

    Some doctors believe that water is important for our health in all kinds of ways. They believe that a great many illnesses and health problems start as a result of dehydration(脱水)—a lack of water in the body. Most people are dehydrated at least some of time, although they probably don't know it. It is surprising to learn that if we feel thirsty, we are already in the first stage of dehydration. In fact, we are advised to drink water before we feel thirsty.

    These doctors think that health problems such as headaches, high blood pressure and asthma(哮喘) could be helped if people drink more water. They also believe that drinking more water can help people who are overweight. Water contains no calories so it will not make us put on weight. If we drink water, we will probably drink less sugary soft drinks such as Coca-cola. Doctors also believe that drinking more water may stop people from overeating. They say that many people think that they are hungry when they are, in fact, thirsty. Doctors suggest, therefore, that we eat less food and drink more water. There are still many health problems that cannot be solved by drinking water, so we should not stop going to seeing the doctor completely. However, if we make a decision to drink water every day, we may find that we need to go to the doctor a lot less often.

    A walk through the galleries of Quebec's Montreal Museum of Fine Arts (MMFA) places individuals face-to-face with some 43,000 artworks ranging from Chinese ceramics(陶瓷制品) to Inuit sculpture.

    While the visiting is an incredible cultural experience, a group of local physicians will soon be able to prescribe(开处方) museum visits as treatment for some illnesses.

"We know that art contributes to neural(神经的) activity," said MMFA director Nathalie Bondil. "What we see is that being in contact with art can really help your well-being."

Hélène Boyer, vice president of a Montreal-based medical association, explains that museum visits have been shown to increase levels of serotonin, a neurotransmitter(神经传导物质) known as the "happy chemical" which helps to lift mood.

    According to Boyer, the small increase in hormones(荷尔蒙)associated with enjoying an afternoon of art is similar to that offered by exercise, making museum prescriptions ideal for the elderly experiencing pain that prevents them from regularly joining in physical activity.

    The museum visits are designed to improve traditional methods. As Bondil notes, spending time in a peaceful environment can provide a welcome distraction. "What is most important is this experience can help them escape from their own pain," she says. "When you enter the museum, you escape from the speed of our daily life."

    "I am convinced that in the 21st century, culture will be what physical activity was for health in the 20th century," said Bondil. "Some people would do well to recall that just in the 19^th century, sports were believed to do harm to the body. Just as doctors now prescribe exercise, they will be able to prescribe a visit to the MMFA."

    While staring out of the window during a flight, not everyone will think carefully about the question why airplanes have rounded windows rather than square ones.

    Over the years, aerospace engineering has made huge steps in airplane technology, meaning planes can carry more passengers and go faster. The planes have also changed shape to increase safety—including the windows. As commercial air travel took off in the mid－20th century, airline companies began to fly at higher altitudes to lower their cost—the air density(密度) is lower up there, creating less drag(阻力)for airplanes. However, higher altitudes came with problems, like the fact human beings can't really survive at 30，000 feet. To make that possible, the cabin was changed to a cylindrical(圆柱体) shape to support the pressure inside. But at first, plane builders left in the standard square windows and this expansion meant disaster. The de Havilland Comet came into fashion in the 1950s. With a closed cabin, it was able to go higher and faster than other aircraft.

    However, where there's a corner, there's a weak spot. Windows, having four corners, have four potential weak spots, making them likely to crash under stress—such as air pressure. By curving the window, the stress that would eventually break the window corner is distributed and the chance of it breaking is reduced. Rounded shapes are also stronger and resist deformation(变形), and can thus survive the extreme differences in pressure between the inside and outside of the aircraft.

    Fortunately, designers figured out the lack of design pretty quick. Now we have nice, rounded airplane windows that can resist the pressure of traveling altitude. It gives being able to gaze out of your window to the world from 35，000 feet a whole new outlook, doesn't it?

    Throughout much of human history, man has been the measure of many, if not all, things. Lengths were divided up into feet and smaller units from the human hand. Other measures were equally characteristic. Mediterranean traders for centuries used the weight of grains of wheat to define (定义) their units of mass. The Romans used libra, forerunner of the pound, by referring to the weight of a carob (角豆树) seed.

    The sizes of similarly named units could also differ. The king's foot, used in France for nearly

    1,000 years after its introduction by Charlemagne in around 790 AD, was, at 32.5cm,around a centimeter shorter than the Belgic foot, used in England until 1300.Greek,Egyptian and Babylonian versions of water in a fixed container varied from one another by a few kilos, Nor was there agreement on such things within countries. In France, where there was no unified (统一的) measurement system at the national level, the situation was particularly terrible. The lieue (former measure of distance), for example, varied from just over 3 km in the north to nearly 6 km in the south.

    Although John Wilkins, an Englishman, first put forward a decimal system (十进制) of measurement in 1668,it was the French who in 1799 made it law. The Système International d'Unités (SI, or the metric system, as it is better known) developed from it and became the official measurement in all countries except Myanmar, Liberia and the United States. Now the International Bureau of Weights and Measures in Paris is set to give the metric system its biggest shake-up yet.

    At a meeting in Versailles, France, on November 16th,2018,the world's measurement bodies are almost certain to approve a decision that will mean four out of the seven base SI units, including the kilogram, will follow the other three, including the metre, in being redefined in terms of the values of physical constants (物理常数).Each of the chosen constants has been measured incredibly precisely, which would mean that from May 20^th 2019 the constants will themselves be fixed at their current values for ever. Any laboratory in the world will then be able to measure, for example, the mass of an object as precisely as the accuracy of their equipment will allow.

    I always feel sorry for world leaders busy dealing with fights between nations. When my three children were young, most days it was hard to keep my house from becoming a battlefield.

    It got worse as they grew older. Three years ago, Zack, then 16, couldn't make it through a day without making his sisters, Alex 11 and Taryn 9, angry.

    My husband and I tried to be understanding the boy at such an age. We reasoned, punished, and left heartfelt notes on his bed about how he was hurting our family. His answer was "I say it because it's true."

    I even tried telling the girls to fight back. Bad idea. Now I had three children at war. Whatever I said to them, they paid no attention. When there was no way out, I told everything to my sister in an e-mail. She replied, "Don't e-mail me. E-mail him."

    Our son was online every day, mailing and talking with his friends. Maybe he would actually hear me this way. I didn't say anything different, but e-mail just took the tension(紧张) away. There'd be no shouting or door banging. Zack wouldn't feel under attack.

    Zack didn't reply for days. When he finally did, his entire message was four small words. I smiled when I read them, "You're right. I'm sorry."

    The children still fought, of course, but Zack changed. Best of all, I now have a better way to talk with not one but three of them. I like it that they don't tune me out as much as they used to. They like not having to listen to me shouting to them. Or as Alex says, "You're so much nicer online."

    All I know is that the house is quiet. But we're talking.