第13单元 · 四档阅读与填词

A star may seem to jump, grow bright, and then grow weak. Most of the time, the star itself shines in the same way. The difference begins much closer to us, in the moving air around Earth.

Near the ground, the air holds warmer and cooler pockets. Each pocket changes the path of the light a little. As the pockets move, the point of light seems to jump, grow bright, or grow weak. In astronomy, this effect is called twinkling.

A far star looks like one tiny point. A planet looks like a tiny round shape instead of one point. Light from different parts of that shape passes through different pockets of air. The changes partly balance one another, so an astronomer sees less change in a planet.

NASA astronaut Owen Garriott remembered that stars did not seem to move when he was above Earth's air. When his view passed through that air, the stars began to jump again. Hubble also stays above most of the moving air, so it can make clear pictures of stars.

In the 1930s, shop owner Sylvan Goldman noticed that customers often stopped shopping when their hand baskets became heavy. Could a cart help? It might let them carry more without making their arms tired.

He put two baskets on a chair with wheels. People could make a larger purchase without holding everything by hand. When shopping ended, workers took off the baskets and closed the chair, so it needed less room.

In 1946, Orla Watson found another answer. His design allowed one cart to move inside another, so a long row needed less floor space. Each one stayed open and was ready for the next person.

Years later, designers at IDEO watched people and workers in shops. They made a steel body that fitted inside another one, held baskets people could take out, and had safer seats for children. The product had changed, but the method was familiar: watch people use it, notice a problem, and test a new design.

In the story, Framton visits a country house to rest. He is a nervous guest who knows almost no one there. A young girl named Vera meets him. His doctor has told him to choose a quiet life for a time.

A large window stands open on a lovely autumn day. The girl says her aunt's husband and brothers went through it to hunt and never came home. She says the aunt still expects them, with one man's white coat over his arm and their small brown dog beside them.

Soon three men walk toward the same window. One carries a white coat, and a brown dog follows them. The lady welcomes them, but Framton believes the sad story. He rushes away without a word. The family cannot understand why their guest ran.

The men are alive; Vera made the sad story up. She used the stuff around the house: the open window, one white coat and the dog. When these things appeared together, Framton thought her story was true. He ran because the lie came first and changed what he saw.

After a storm, Robinson Crusoe reaches a deserted island alone. A wide stretch of sea separates him from the wreck, which lies offshore. He sees no road, house, or other person.

The wreck still holds food and tools, so Crusoe crosses the rough water again and again. He brings back guns, rope, cloth, and grain. At his camp, he spreads recovered sailcloth wide to make a tent and builds a fence around his stores.

Months turn into years. He plants grain and raises goats. Patience becomes a practical virtue: weather ruins some work, sickness stops him, and every improvement takes time. He saves seed for the next crop and plans around the weather.

Then Crusoe finds one human footprint in the sand. It proves that somebody has stood there, but it tells him nothing about who came or why. The mark is small; the possible stories around it are not. Familiar paths now feel exposed because he can no longer assume he is alone.

A museum exhibition can use digital media without treating every tool alike. Before adapting a fragile exhibit, a designer asks what the visitor should continue to see. The real object may stay in view, or a computer-made scene may replace the room. That choice guides the exhibition's adaptation to digital media.

In NIST's description of VR, the user is cut off from the real world and enters a virtual one. A headset can make a gallery disappear behind a reconstructed workshop or another computer-made space. The visitor gains a strong sense of being elsewhere, but the original exhibit is no longer visible during that experience.

AR keeps a different relationship with the room. NIST says the user still sees the real world while graphics appear over it. Smithsonian Education describes the same blend of real and virtual space. In a museum, a phone might place a label or a model beside an object that remains in sight.

NIST uses WebXR as a broad term that includes VR, AR and MR. The letters MR name another member of that family; by themselves, they do not explain what a visitor will see or control. A clear exhibition description names the physical scene, the digital layer and the visitor's action. Before a team chooses a tool, it should write that description first.

Fermilab's Open Lab is a drop-in MakerSpace session where families can build, code, create and ask questions. All ages are welcome, although the activities are designed mainly for elementary-age students. No registration is required. Entry is first-come, first-served while supplies last. The lab's capacity and remaining materials determine how many families can join, so arriving does not guarantee a spot at a worktable.

Other MakerSpace programmes use narrower age bands. In STEM Spotlight, children aged eight to ten work with a guardian and explore science careers. Visualizing STEM gives learners aged eleven to fourteen four days of physics projects. This structure changes the time and task to suit different groups instead of sending every learner along the same route.

Teacher Studio extends the idea to formal and informal educators. Each month, participants make something together and share ideas for their learners. They may join online or at one of four hubs. Its hybrid format creates a community capable of sharing ideas across subjects, grade levels and institutions.

Open Lab also makes engineering visible through ordinary materials. On one day, makers may build a city from cardboard, paper and tape; on another, they may build circuits on paper. Both use materials that are easy to cut, fold or reconnect. A beginner can change one part, see the result and try again.

After a person has been found guilty of a crime, a risk tool may estimate a defined future event, such as another arrest. It does not determine whether the earlier offence occurred. In the criminal justice system, a judge or officer must understand what the score predicts, which population shaped it and what decision it is meant to inform.

Accuracy is made of several measures. Analysts examine correct predictions, false positives and false negatives across groups. A cutoff can improve one measure while worsening another. These comparisons help them discriminate between kinds of error instead of hiding every difference inside one average.

The calculation is only one part of the process. Historical records may carry old inequalities, and staff may use the same score differently across offices. Prejudice can enter through categories, missing information or unequal access to help. If those conditions burden one group more heavily, discrimination may persist even when the formula has been carefully tested.

Human judgment therefore brings duties. Agencies need to record the tool's purpose, monitor results, train users and explain departures from a score. The moral standard is practical: the institution should be able to show how evidence, error and responsibility led to the final action.

At sixteen, a student may receive a list of optional courses. The list looks open, but schools and colleges have already decided what to offer and when to teach it. Department for Education studies combined student records with interviews to examine how availability, earlier results, advice, enjoyment and career ideas shaped each individual choice.

The timetable creates the first boundary. Compulsory subjects occupy fixed periods, and a clash can remove another option. An entry criterion may close a route even when interest is strong. A course offered elsewhere can still be difficult to reach because of travel or limited information.

Advice then changes how the remaining possibilities are understood. A teacher can explain a qualification, while a role model can make a future job easier to imagine. Confidence, family knowledge, enjoyment and previous marks continue to matter, so the same advice may guide one learner and leave another uncertain.

Records reveal broad patterns; interviews explain reasons a table cannot show. Together they suggest an approach schools can adopt: publish realistic combinations early, explain entry rules and ask what practical barrier stands behind a missing choice. The harder question remains: which missing choice came from preference, and which disappeared before the student had a real chance to choose?

A search on the Smithsonian website brings up an odd little machine from Milwaukee. The 1868 physical patent model has eleven piano-like keys—six white and five black—while the patent drawing shows twenty-one. Its mechanism moved type bars, paper and the carriage, but the mismatch between object and drawing leaves an unfinished stage in invention and a historical puzzle.

Following the record forward leads to the Sholes and Glidden Type Writer that Remington sold in 1874. Its black case and sewing-machine stand gave buyers a familiar shape. A user would insert paper around the platen and operate a treadle for carriage return. The first model printed capital letters only; a later one added lower case while keeping the QWERTY layout.

Related records open onto the offices that adopted the machine. Sales began slowly, then growing corporations created more work for specialised office equipment. A typist became a recognised occupation, and the typewriter helped expand white-collar jobs for women. The typical office changed through several forces, including faster paper transactions and the machine built to handle them.

The website keeps the early model and commercial machine on separate pages. A reader can still place them side by side. The patent summary introduces an experimental mechanism; the commercial record follows the machine into offices. Together they form a web of inventors, manufacturers and workers. A small eleven-key object can therefore open a much larger social history.

A product footprint often arrives as one polished total, although the calculation begins by drawing boundaries. Life-cycle assessment follows linked stages from raw-material acquisition through production, use and disposal. A factory-gate study may answer a useful question, but a reader should not assume that it represents the whole chain. Before comparing totals, the reader needs the service being measured, the stages included and the conditions under which the product is used.

The functional unit defines the service. Counting one shopping bag is weaker than comparing the delivery of a stated load over a stated number of trips. A durable item may require more material at first yet perform the service many times. The consumer receives that service rather than merely possessing an object. Without a common function, a comparison can reward a lighter object while ignoring how often it must be replaced.

The system boundary defines the processes. Analysts decide whether to include extraction, transport, factory energy, washing, repair, recycling and final disposal. They may exclude a small flow when data are unavailable, but the exclusion should be visible. Two studies can use sound measurements and still reach different rankings because their boundaries answer different questions. A changed boundary alters the model without making either measurement automatically false.

Every model also contains an assumption about behaviour. How far will the product travel? How much energy will it consume during use? How many times will it perform the function? A result can be approximately right for one pattern of consumption and misleading for another. Worldwide averages help when local information is absent, but they can hide electricity sources, transport distances, repair habits and waste systems that vary by place.

Conditional does not mean useless. It means that the number belongs to a stated decision. A careful report exposes its function, boundary, data sources, exclusions and uncertainty before displaying the final total. A careful reader asks whether those choices match the proposed action. More decimal places cannot repair a mismatched scope; a transparent model is valuable because another person can understand, challenge and improve it.

When Rachel Carson's Silent Spring appeared in 1962, chemical pesticides were widely valued for protecting crops and controlling disease. Carson documented how careless, large-scale use could kill organisms beyond the intended insects and move through connected living systems. The book presented environmental damage as a public crisis with consequences that could not be confined to one field or season.

Carson's policy position was selective. She accepted that pesticides could be useful, while calling for stronger research, safer application and alternatives to especially dangerous chemicals. She was critical of routine spraying undertaken without adequate evidence. That distinction matters because her argument concerned how chemicals were used, not a demand to end every use immediately.

The controversy did not wane after publication. Industry critics challenged her science and warned that tighter controls could harm farming and disease prevention. Some attacks also criticised Carson's professional integrity, shifting attention from the evidence to the person presenting it. Readers therefore had to judge competing claims about benefits, risks and the burden of proof.

Public argument was followed by formal review. The federal government examined pesticide policy, and Carson testified before Congress in 1963. Those steps brought evidence into hearings and agencies with authority to compare scientific findings, practical needs and legal responsibilities.

A subsequent regulatory history included the Environmental Protection Agency's 1972 hearings and order cancelling most remaining DDT uses in the United States. Publication, controversy, testimony and administrative judgement were separate stages. Silent Spring's durable consequence was to make environmental risk a public question that institutions had to answer with evidence and review.

Apollo 13 lifted off from Florida at 1:13 p.m. CST on 11 April 1970. As the spacecraft gained altitude, the crew and Mission Control followed a plan for the third lunar landing. Aquarius was built to carry two astronauts down to the Moon, while the command module Odyssey would bring all three home. Each vehicle, procedure and team had a defined role, and for two days the mission followed that design.

Then an oxygen tank exploded about 200,000 miles from Earth. Odyssey lost its normal electricity, light and water, and the landing was abandoned. Mission Control now had to track the spacecraft's location, recover a safe path and ensure that power, water and breathable air would last. Aquarius became a lifeboat, although it had been designed for two people for two days and now had to support three for roughly four.

Controllers had to allocate a limited supply of energy across the return. They shut down nonessential systems until Aquarius used about one-fifth of its normal power, and some of that energy charged Odyssey's batteries for re-entry. Carbon dioxide created a different problem: Odyssey's square filters would not fit Aquarius's round openings. Plastic bags, cardboard and tape formed an adapter, allowing available filters to work in the new system.

Navigation could not be planned in isolation. An earlier course correction had taken Apollo 13 away from a free-return path, so new engine burns had to restore it. Debris from the explosion blocked the usual navigation stars; the crew used the Sun to check alignment instead. Engineers tested unfamiliar procedures in simulators before sending them up. Controllers had to be sure that engine timing, spacecraft attitude and every demand on power still fitted one return sequence.

Lovell, Swigert and Haise splashed down safely on 17 April. NASA later called Apollo 13 a successful failure. The lunar landing was lost, but coordinated changes to power, air and navigation brought the crew home. The phrase preserves both outcomes and the difficulty of connecting them. Investigation and operational lessons then shaped future missions.