A new experiment shows that the more energy consumed by a clock, the more accurate its timekeeping.
Clocks consume energy and release heat. A kitchen clock, for example, does this by using up its battery. Generally the most accurate clocks require the most energy, which suggests a fundamental connection between energy consumption and accuracy. This is what an international team of scientists from Lancaster. Oxford, and Vienna set out to test.
To do this, they built a particularly simple clock, consisting of a super-thin membrane (薄膜), combined with an electronic circuit. Each vibration (振动) of the membrane generated one electrical tick (滴答). The inventive aspect of this design is that it is powered simply by heating the membrane, while the complete flow of energy through the clock can be measured electrically.
The scientists found that the more heat they supplied, the more accurately the clock ran. In fact, the accuracy was directly relative to the heat released. To make the clock twice as accurate, they needed to supply twice as much heat.
The experiment shows a similarity between the operation of a clock and a steam engine. With a steam engine there is fundamental restriction on how much heat we must supply to do a desired amount of work. This restriction is the famous Second Law of Thermodynamics (热力学) which is central to modern engineering. What this experiment suggests is that clocks, like engines, are restricted by the Second Law, with their output being accurate ticks instead of mechanical work.
Dr Edward Laird of Lancaster University said: “This experiment suggests that clocks are also restricted by thermodynamics. It also poses an interesting question: are all possible clocks limited in this way, or is it just a characteristic of the ones we have studied?”
Interestingly, many everyday clocks have an efficiency that is close to what the scientists’ analysis predicts. For example, their analysis predicts that a wristwatch whose accuracy per tick is one part in ten million must consume at least a microwatt of power. In fact, a basic wristwatch usually consumes only a few times this amount. The laws of thermodynamics, discovered in the nineteenth century, are still finding new applications today.
1. What do the scientists want to test about clocks?| A．Whether to restrict their heat supply. |
| B．How energy influences their accuracy. |
| C．How to make them particularly simple. |
| D．Whether they are similar to steam engines. |
| A．The restriction from the Second Law. |
| B．The law behind their operation. |
| C．The accuracy of their work. |
| D．The form of their output. |
| A．Further studies should be done. |
| B．More questions should be raised. |
| C．Restrictions on clocks should be lifted. |
| D．Suggestions of the experiment should be adopted. |
| A．The Second Law of Thermodynamics. |
| B．The energy consumption of clocks. |
| C．A new experiment. |
| D．A simple clock. |
相似题推荐
【推荐1】Humans are the only creature that gets around by standing up and putting one foot in front of the other. Our ability to walk upright has allowed humankind to travel great distances and survive changing climates, environments and landscapes.
Countless scientific studies have found that walking is really good for us and this simple act can provide a number of health implications, which help people live longer. In fact, a walking routine, if done properly, might be the only exercise people need.
How much walking should one aim for? You’ve likely heard we need 10,000 steps a day. That’s about 5 miles. But contrary to popular belief, this recommendation doesn’t come from science. Instead, it is from a 1960s advertising campaign to promote a pedometer (计步器) in Japan. Perhaps because it’s a round number and easy to remember, it stuck.
Since the 1960s, researchers have studied the 10,000-steps-a-day standard and have turned up mixed results. Although 10,000 steps is certainly a healthy and worthwhile goal, it’s not fit for all.
For instance, a recent Harvard University study involving more than 16,000 senior women found that those who got at least 4,400 steps a day greatly reduced their risk of dying early when compared with less active women. The study also noted that these benefits continued up to 7,500 steps. This 7,500 mark isn’t surprising: It’s similar to common public health recommendations, such as the Centers for Disease Control and Prevention’s recommendation of 150 minutes of moderate (适度的) physical activity a week for adults.
1. What does the underlined word “implications” in Paragraph 2 refer to?| A．Benefits | B．Problems. | C．Habits. | D．Manners. |
| A．A Harvard University study. |
| B．Science research on health. |
| C．A pedometer advertisement. |
| D．Public health recommendation. |
| A．7,500-steps-a-day standard is the best choice for all. |
| B．More than 16,000 old people were involved in the study. |
| C．Those who walk at least 4,400 steps a day won’t die early. |
| D．150-minute moderate exercise a week for adults is advised. |
| A．The more you walk a day, the healthier you will be. |
| B．We can benefit from continuous and proper walking. |
| C．Walking upright helps humankind to explore the world. |
| D．Advertisements can always tell us some scientific suggestions . |
【推荐2】On Jan. 9, 2007, 10 years ago today, Steve Jobs formally announced Apple’s“revolutionary mobile phone”— a device that combined the functionality of an iPod, phone and Internet communication into a single unit, controlled by touch.
As smartphones have proliferated, so have questions about their impact on how we live and how we work. Often the advantages of convenient, mobile technology are both obvious and taken for granted, leaving more subtle topics for concerned discussion: Are smartphones disturbing children’s sleep? Is an inability to get away from work having a negative impact on health? And what are the implications for privacy?
But today, on the 10th anniversary of the iPhone, let’s consider a less obvious advantage: the potential for smartphone technology to revolutionize behavioral science. That’s because a large proportion of the species is in continuous contact with technology that can record key features of an individual’s behavior and environment.
Researchers have already begun to use smartphones in social scientific research, recording people’s activity using the device’s built-in sensors. These studies are confirming, challenging and extending what’s been found using more traditional approaches, in which people report how they behaved in real life or participate in artificial laboratory-based tasks.
One of the studies has used smartphone-based data collection with a built-in sensor to paint an accurate pictures of how mood is affected by a person’s location. The data came from more than 12,000 members of the general public. Twice during the day, they were prompted(促使)to report their mood and location, with location information additionally collected from the phone’s location sensors. Using both kinds of location data, the study found that people reported significantly more positive moods in locations that typically involve social interactions (such as a café or friend’s house) than at home, and more positive moods at home than at work.
Other studies have used sensor data to draw some kinds of inferences. For instance, a study published in 2015 followed 48 students over the course of a 10-week school term. Using a combination of location, activity and audio sensors, the researchers could infer students’ patterns of class attendance, study time, physical activity and socializing. These variables, in turn, predicted student GPA with surprisingly high accuracy.
These studies are just first steps. With more data and better methods for analysis, researchers will be able to identify how different experiences, behaviors and environments relate to each other and evolve over time more accurately. The right combination of data and analysis can also help individuals identify unique characteristics of their own behavior, including conditions that need some form of treatment.
Smartphone-based data collection comes at an opportune time in the evolution of psychological science. Today, the field is moving away from a focus on laboratory studies with undergraduate participants towards more complex, real-world situations studied with more varieties of groups of people. Smartphones offer new tools for achieving these ambitions, offering rich data about everyday behaviors in a variety of contexts.
So here’s another way in which smartphones might transform the way we live and work: by offering insights into human psychology and behavior and, thus, supporting smarter social science.
1. What does the author say about the negative impact of smartphones?| A．It has been overshadowed by the positive impact. |
| B．It has more often than not been taken for granted. |
| C．It is not so obvious but has caused some concern. |
| D．It is subtle but should by no means be overstated. |
| A．It is based on huge amounts of carefully collected data. |
| B．It makes use of the questionnaire method. |
| C．It is often expensive and time-consuming. |
| D．It relies on lab observations and participants’ reports. |
| A．detect their unusual behaviors. |
| B．maintain a positive state of mind. |
| C．live their lives in a unique way. |
| D．cope with abnormal situations. |
| A．They are going through a period of painful transition. |
| B．They are increasingly focused on real-life situations. |
| C．They are conducted in a more rigorous manner. |
| D．They are mainly targeted towards undergraduates. |
【推荐3】
In meditation (冥想), people sit quietly and focus their attention on their breath. As they breathe in and out, they attend to their feelings. As thoughts go through their minds, they let them go. Breathe. Let go. Breathe. Let go.
According to a recent study at the Insight Meditation Society in Barre, Massachusetts, three months of training in this kind of meditation causes a marked change in how the brain allocates (分配) attention. It appears that the ability to let go thoughts that come into mind frees the brain to attend to more rapidly changing things and events in the outside world. Expert mediators are better than other people at catching such fast—changing stimuli (刺激), like facial expressions.
The study provides evidence for changes in the workings of the brain with mental training. People can learn and improve abilities of all sorts with practice, everything from driving to playing the piano. The study has shown that meditation is good for the brain. It appears to reduce pressure and promote a sense of well-being.
In an experiment, 17 volunteers with no meditation experience in the experimental group spent three months meditating 10 to 12 hours a day. A control group also with no meditation experience meditated for 20 minutes a day over the same period. Both groups were then given the tests with two numbers in a group of letters. As both group looked for the numbers, their brain activity was recorded.
Everyone could catch the first number. But the brain recordings showed that the less experienced mediators tended to grasp the first number and hang onto it, so they missed the second number. Those with more experience gave less attention to the first number, as if letting it go, which led to an increased ability to grasp the second number. This shows that attention can change with practice.
Just ask Daniel Levision, who meditated for three months as part of the study. "I am a much better listener," he said. "I do not get lost in my own personal reaction to what people are saying."
1. Meditations manage their daily tasks better because they _____ .| A．are given less pressure |
| B．allocate their attention better |
| C．have more stimuli for life |
| D．practice them more frequently |
| A．were more likely to catch both of the numbers. |
| B．were used to memorizing numbers in groups. |
| C．usually ignored the first number observed. |
| D．paid more attention to numbers than to letters. |
| A．meditation improves one's health |
| B．brain activity can be recorded |
| C．human attention can be trained |
| D．mediators have a good sense of hearing |
【推荐1】The e-commerce boom has fueled demand for warehouses (仓库). And the increasing demand is mostly linked to online shopping, because Internet shoppers are always expected to provide a wider variety of goods. Vacancy rates (空仓率) have therefore decreased greatly, from 10% across America and Europe a decade ago to just 5% now. In some places, like Toronto and Tokyo, they are below 2%.
The value of existing assets of warehouses is ballooning as a result. This in turn is attracting more investment. However, people’s enthusiasm for building new warehouses is now starting to run up against obstacles. The first is lack of space, especially in densely populated cities. The problem has grown so acute in parts of Germany that delivery lorries operate from sites across the border in Poland and France. High costs, restrictive zoning rules and current rents make it difficult to convert existing properties, such as struggling shopping malls, into distribution centers.
Public hostility to new sites is also growing. Large warehouses are noisy and operate around the clock. Suburban homeowners across America and Europe worry about pollution from lorries. Even where developers promise thousands of jobs, politicians complain that these will be low-skilled, or soon replaced by robots. Five Conservative members have called on Britain’s government, run by their own party, to stop a huge warehouse from being built in south-east England.
Warehouse owners are getting more crentive. Amazon is changing former golf courses in America into distribution centers. The online giant is also converting an empty car park in central London into a delivery hub. Less creatively, developers are raising rents and it’s estimated that they will go up by 6% globally this year. That may upset e-merchants.
1. What do the figures quoted in the first paragraph illustrate?| A．Online shopping is driving the demand for warehouses. |
| B．A large number of goods are sold at reduced prices. |
| C．The number of online shoppers has declined. |
| D．Goods in Toronto and Tokyo are less popular. |
| A．Because the shopping mall is not large enough. |
| B．Because people’s enthusiasm is not high enough. |
| C．Because delivery truckers don’t like the idea. |
| D．Because the cost of doing so is high. |
| A．Agreement. | B．Awareness. | C．Opposition. | D．Preference. |
| A．Warehouse owners are getting more creative. |
| B．Some vacant sites are converted into warehouses. |
| C．It’s harder for them to park in the center of London. |
| D．Rents for warehouses are rising all over the world. |
【推荐2】Alongside her impressive musical career, Leona Lewis is also the owner of a vegan (素食主义的) coffee shop, Coffee And Plants. She has great enthusiasm for the coffee shop and reveals the drink flavors that they’ve been working on lately. “We’ve just rolled out our new pumpkin drink at the coffee shop. It’s called Pumpkin Pie, and it’s really good! We use all real pumpkin puree, not flavored syrup.”
Coffee And Plants is a real passion project for Lewis, being fully plant-based. She has a long history of animal activism (行动主义), starting with going vegetarian (素食者) at the age of 12 after going on shopping trips with her mum and seeing protesters with animal testing signs. “I was so upset, I said, ‘Mum, I have to help the animals’,” she says. “That became my mission as a kid, and it’s fed into every aspect of my life.”
Her animal activism grew alongside her fame: in 2011 she supported a campaign to ban the use of wild animals in circuses, and in 2013 she released a cruelty-free makeup line with The Body Shop. When it came to opening a coffee shop, making it plant-based was a no-brainer.
“I wanted it to be plant-based because I’m plant-based,” she says. “I would often go into coffee shops and see milk cartons piled up high and think, how many cows are being milked for this? The dairy industry and mass farming—it’s so cruel and harms the environment too.”
Environmental awareness is also at the heart of Coffee And Plants, with all cups being recyclable. But ultimately, Lewis is hoping for a more widespread mindset shift. “What we really try and get people to do is actually bring in their own bottles to refill, or we encourage them to sit in and have a coffee in a cup instead,” she explains. “We need a mindset shift where we start to think, OK, we shouldn’t really be using stuff that just goes in the bin.”
1. What does the phrase “rolled out” underlined in the first paragraph mean?| A．improved | B．discovered | C．denied | D．launched |
| A．She hated to eat animal meat. | B．She wanted to protect animals. |
| C．She was inspired by her mom. | D．She was given a great mission. |
| A．To show Lewis influence on business. |
| B．To compare Lewis’ different activities. |
| C．To prove that the makeup line is plant-based. |
| D．To give an example of Lewis’ animal activism. |
| A．People have to start using reusable things. |
| B．The mind shift is quite easy to accomplish. |
| C．People shouldn’t use cups in the coffee shop. |
| D．Only vegetarians can go into the coffee shop. |
【推荐3】At the start of the 20th century, an American engineer named John Elfreth Watkins made predictions about life today. His predictions about slowing population growth, mobile phones and increasing height were close to the mark. But he was wrong in one prediction: that everybody would walk 10 miles a day.
Today, in Australia, most children on average fall 2, 000 steps short of the physical activity they need to avoid being overweight. In the early 1970s, 40 per cent of children walked to school, while in 2010, it was as low as 15 percent.
The decline is not because we have all become lazy. Families are pressed for time, many with both parents working to pay for their house, often working hours not of their choosing, living in car-dependent neighborhoods with limited public transport.
The other side of the coin is equally a deprivation: for health and well-being, as well as lost opportunities (机会) for children to get to know their local surroundings. And for parents there are lost opportunities to walk and talk with their young scholar about their day.
Most parents will have eagerly asked their child about their day, only to meet with a “good”, quickly followed by “I’m hungry”. This is also my experience as a mother. But somewhere over the daily walk more about my son’s day comes out. I hear him making sense of friendship and its limits. This is the unexpected and rare parental opportunity to hear more.
Many primary schools support walking school-bus routes (路线), with days of regular, parent-accompanied walks. Doing just one of these a few times a week is better than nothing. It can be tough to begin and takes a little planning-running shoes by the front door, lunches made the night before, umbrellas on rainy days and hats on hot ones-but it's certainly worth trying.
1. Why does the author mention Watkins' predictions in the first paragraph?| A．To make comparisons. | B．To introduce the topic. |
| C．To support her argument. | D．To provide examples. |
| A．Plain laziness. | B．Health problems. |
| C．Lack of time. | D．Security concerns. |
| A．She can get relaxed after work. | B．She can keep physically fit. |
| C．She can help with her son's study. | D．She can know her son better. |
