Pulling strings to build pyramids
No one knows exactly how the pyramids were built. Marcus Chown reckons the answer could be ‘hanging in the air’.
The pyramids of Egypt were built more than three thousand years ago, and no one knows how. The conventional picture is that tens of thousands of slaves dragged stones on sledges. But there is no evidence to back this up. Now a Californian software consultant called Maureen Clemmons has suggested that kites might have been involved. While perusing a book on the monuments of Egypt, she noticed a hieroglyph that showed a row of men standing in odd postures. They were holding what looked like ropes that led, via some kina of mechanical system, to a giant bird in the sky. She wondered if perhaps the bird was actually a giant kite, and the men were using it to lift a heavy object.
Intrigued, Clemmons contacted Morteza Gharib, aeronautics professor at the California Institute of Technology. He was fascinated by the idea. ‘Coming from Iran, I have a keen interest in Middle Eastern science/ he says. He too was puzzled by the picture that had sparked Clemmons’s interest. The object in the sky apparently had wings far too short and wide for a bird. The possibility certainly existed that it was a kite/ he says. And since he needed a summer project for his student Emilio Graff, investigating the possibility of using kites as heavy lifters seemed like a good idea.
Gharib and Graff set themselves the task of raising a 4.5-metre stone column from horizontal to vertical, using no source of energy except the wind. Their initial calculations and scale-model wind-tunnel experiments convinced them they wouldn’t need a strong wind to lift the 33.5-tonne column. Even a modest force, if sustained over a long time, would do. The key was to use a pulley system that would magnify the applied force. So they rigged up a tent-shaped scaffold directly above the tip of the horizontal column, with pulleys suspended from the scaffold’s apex. The idea was that as one end of the column rose, the base would roll across the ground on a trolley.
Earlier this year, the team put Clemmons’s unlikely theory to the test, using a 40-square- metre rectangular nylon sail. The kite lifted the column clean off the ground. “We were absolutely stunned,” Gharib says. “The instant the sail opened into the wind, a huge force was generated and the column was raised to the vertical in a mere 40 seconds.”
The wind was blowing at a gentle 16 to 20 kilometres an hour, little more than half what they thought would be needed. What they had failed to reckon with was what happened when the kite was opened. There was a huge initial force – five times larger than the steady state force,’ Gharib says. This jerk meant that kites could lift huge weights, Gharib realised. Even a 300-tonne column could have been lifted to the vertical with 40 or so men and four or five sails. So Clemmons was right: the pyramid, builders could have used kites to lift massive stones into place. ‘Whether they actually did is another matter,’ Gharib says. There are no pictures showing the construction of the pyramids, so there is no way to tell what really happened. ‘The evidence for using kites to move large stones is no better or worse than the evidence for the brute force method,’ Gharib says.
Indeed, the experiments have left many specialists unconvinced. The evidence for kite¬lifting is non-existent,’ says Willeke Wendrich, an associate professor of Egyptology at the University of California, Los Angeles.
Others feel there is more of a case for the theory. Harnessing the wind would not have been a problem for accomplished sailors like the Egyptians. And they are known to have used wooden pulleys, which could have been made strong enough to bear the weight of massive blocks of stone. In addition, there is some physical evidence that the ancient Egyptians were interested in flight. A wooden artefact found on the step pyramid at Saqqara looks uncannily like a modern glider. Although it dates from several hundred years after the building of the pyramids, its sophistication suggests that the Egyptians might nave been developing ideas of flight for a long time. And other ancient civilisations certainly knew about kites; as early as 1250 BC, the Chinese were using them to deliver messages and dump flaming debris on their foes.
The experiments might even have practical uses nowadays. There are plenty of places around the globe where people have no access to heavy machinery, but do know how to deal with wind, sailing and basic mechanical principles. Gharib has already been contacted by a civil engineer in Nicaragua, who wants to put up buildings with adobe roofs supported by concrete arches on a site that heavy equipment can’t reach. His idea is to build the arcnes horizontally, then lift them into place using kites. ‘We’ve given him some design hints,’ says Gharib. We’re just waiting for him to report back.’ So whether they were actually used to build the pyramids or not, it seems that kites may make sensible construction tools in the 21 st century AD.
- Giải thích từ vựng
- String (n) /strɪŋ/ dây, băng, dải
Eg: When you pull the strings, the puppet’s arms and legs move.
Could you tie this piece of string for me?
- Conventional (a) /kənˈven.ʃən.əl/ truyền thống/ theo tập quán, theo tục lệ
Eg: Autosuggestive techniques can help in the treatment of diseases which cannot be cured by conventional medicine.
He turned out to be a very conventional young man.
- Drag (v) /dræɡ/ kéo lê, kéo trượt trên bề mặt
Eg: Pick the chair up instead of dragging it behind you!
She dragged the canoe down to the water.
- Back sth up (phrasal verb ) chứng minh điều gì đó là đúng
Eg: His claims are backed up by recent research.
I’ll back you up if they don’t believe you.
- Involve (v) /ɪnˈvɒlv/ bao gồm, có liên quan, dính líu tới
Eg: Research involving the use of biological warfare agents will be used for defensive purposes.
The new mayor is keen to involve the local community in his plans for the city.
They said that the job would involve travelling to Paris.
- Monument (n) /ˈmɒn.jə.mənt/ lăng mộ/ đài tưởng niệm/ cong trình kiến trúc lớn
Eg: While in Washington, D.C., we visited a number of historical monuments.
In the square in front of the hotel stands a monument to all the people killed in the war.
- Posture (n) /ˈpɒs.tʃər/ tư thế; dáng điệu, dáng bộ
Eg: Newton sat back in a reclining posture.
Back pains can be the result of poor posture.
- Via (prep) /ˈvaɪə/ qua, theo đường
Eg: We hope to bring you a live report from Ouagadougou via our satellite hook-up.
I’ll be back a little late because I’m going via town.
- Intrigue (v) /ɪnˈtriːɡ/ hấp dẫn, gợi thích thú, kích thích tò mò
Eg: Throughout history, people have been intrigued by the question of whether there is intelligent life elsewhere in the universe.
- Puzzle (v) /ˈpʌz.əl/ làm bối rối, làm khó xử
Eg: It puzzles me why she said that.
The findings of the survey puzzle me – they’re not at all what I would have expected.
Management are still puzzling about how the accident could have happened.
- Spark (v) /spɑːk/ khuấy động, làm cho hoạt động
Eg: This proposal will almost certainly spark another countrywide debate about immigration.
Một số từ đồng nghĩa:
- Cause Firefighters determined that a campfire spark caused the wildfire.
- Bring about Many illnesses are brought about by poor diet and lack of exercise.
- Result in The fire resulted in damage to their house.
- Lead to Reducing speed limits has led to fewer deaths on the motorways.
- Make The heat is making me tired.
- Arouse It’s a subject that has aroused a lot of interest.
- Apparently (adv) /əˈpær.ənt.li/ nhìn bên ngoài, hình như
Eg: Apparently he’s had enough of England and is going back to Australia.
- Column (n) /ˈkɒl.əm/ cột, trụ
Eg: The roof of the temple was held up by a row of thick stone columns.
- Pulley (n) /ˈpʊl.i/ ròng rọc
Eg: The blocks of stone had to be lifted into position with a system of pulleys.
- Magnify (v) /ˈmæɡ.nɪ.faɪ/ khuếch đại, phóng to, mở rộng
Eg: Although your skin looks smooth, when magnified you can see a lot of little bumps and holes.
- Rig up (phrasal verb) lắp dặt, lắp ráp, dựng
Eg: They rigged up an antenna on their radio to intercept phone calls.
- Massive (a) /ˈmæs.ɪv/ to lớn, đồ sộ; chắc nặng
Eg: he steel industry is coddled by trade protection and massive subsidies.
Meanwhile, the massive aerial bombardment/bombing of military targets continued unabated.
- Unconvinced (a) /ˌʌnkənˈvɪnst/ không tin, hoài nghi
Eg: I remain unconvinced of the need for change.
- Harness (v) /ˈhɑː.nəs/ khai thác, sử dụng
Eg: There is a great deal of interest in harnessing wind and waves as new sources of power.
Collocation
- harness energy/ideas/skills
- harness the power of sth
- Bear (v) /beər/ mang, cầm, vác, đội, đeo, ôm
Eg: The strain must have been enormous but she bore it well.
Tell me now! I can’t bear the suspense!
Một số từ đồng nghĩa :
- endure She endured years of hip pain before seeing a surgeon.
- Suffer She suffers from severe asthma.
- Accept I have finally accepted that I can’t change who he is.
- Resign yourself to I have resigned myself to the fact that I’ll never work again.
- Artefact (n) /ˈɑː.tə.fækt/ đồ tạo tác (do người tiền sử tạo ra, để phân biệt với những đồ vật lấy sẵn trong thiên nhiên)
Eg: The museum’s collection includes artefacts dating back to prehistoric times.
- Uncannily (adv) /ʌnˈkæn.əl.i/ kỳ lạ, phi thường, huyền bí
Eg: Her predictions turned out to be uncannily accurate.
His new girlfriend looks uncannily like his ex-partner.
- Glider (n) /ˈɡlaɪ.dər/ tàu lượn
Eg: Before the invention of gasoline motors, the only planes were gliders.
In the 1960s, some people began flying a new kind of small glider off the tops of hills.
- Date from (phrasal verb) có từ, bắt đầu từ, kể từ
Eg: This map dates from the 14th century.
- Practical (a) /ˈpræk.tɪ.kəl/ thực tế, thực tiễn, thiết thực
Eg: Qualifications are important but practical experience is always a plus.
The service offers young people practical advice on finding a job.
- Deal with (phrasal verb) giải quyết, xử lý, ứng phó với
Eg: They employed him because of his reputed skill in dealing with the press.
I admire her forthright way of dealing with people.
Mr. Nixon may well have had a no-holds-barred approach to dealing with political adversaries.
- Put up (phrasal verb) dựng lên
Eg: They’re planning to put a hotel up where the museum used to be.
Một số từ đồng nghĩa:
- Build The house was built in the 1950s.
- Construct The company wants to construct a 175-mile pipeline.
- Erect It’s unlawful to erect a building until you get approval.
- Assemble He has a job assembling furniture in a warehouse.
- Put together Without the instruction sheet, I’ve got no idea how to put all these parts together.
- Arch (n) /ɑːtʃ/ mái vòm, hình vòm
Eg: n many churches the side aisles are separated from the central aisle by a row of arches.
Passing through the arch, you enter an open courtyard.
- Sensible (a) /ˈsen.sə.bəl/ hợp lý, đúng đắn
Eg: I think the sensible thing to do is call and ask for directions.
It would seem more sensible to do the research now before we start on the project.
- Additional (a) /əˈdɪʃ.ən.əl/ thêm vào, phụ vào, tăng thêm
Eg: The doctor has made an initial diagnosis, but there’ll be an additional examination by a specialist.
They looked to the government for additional support.
- Resemble (v) /rɪˈzem.bəl/ giống với (người nào, vật gì)
Eg: You resemble your mother very closely.
His latest sculpture resembles an enormous seashell.
- Luyện tập
Bài 1: Chọn từ trong khung để hoàn thành các câu bên dưới
| involves | backed up | posture | puzzling | via |
| monument | conventional | drag | intrigues | string |
- They rejected what they saw as the hypocrisy of …………………………. society.
- Could you roll up that ………………………………………… for me?
- The rebels ……………………………………………. their demands with threats.
- Nearly one home in ten across the country is wired up to receive TV ………………………………. cable.
- Try to maintain an upright ……………………………………
- The ………………. stands as a chilling reminder of man’s inhumanity to man.
- The dog managed to ………………………….. the box into the room by itself.
- Her job ………………………………………. filing and other general office work.
- Scientists are …………………………………….. over the results of the research.
- It ………………………… me that no one appears to have thought of this before.
Bài 2: Chọn đáp án đúng để điền vào chỗ trống
- His resignation was ……………………………. for personal rather than professional reasons. A. uncannily B. apparently
- The visit of the G20 leaders ……………………………….. off mass demonstrations. A. sparked B. intrigued
- Nelson’s …………………… in Trafalgar Square is one of London’s best-known landmarks. A. Posture B. Column
- I ……………………….. a temporary radio aerial from a coat hanger. A. rigged up B. dated from
- The jury were ………………………………….. that he was innocent. A. unconvinced B. conventional
- Plans to help developing countries ………………………… the power of technology are important in the fight against global warming. A. bear B. harness
- The museum has a superb collection of ancient ………………………… from Nubia. A. artefacts B. gliders
- It’s all very well knowing things in theory but what you need to gain is ……………………….. experience. A. practical B. massive
- You have to have such a lot of patience when you’re ………………………… kids. A. putting up B. dealing with
- An ………………………. grant has enabled the team to push forward with research plans. A. additional B. practical
- ………………….., he knows all about Anna, and urges her to cancel the wedding. A. Apparently B. Uncannily
- The scenery was moved across the stage by ropes and …………………………. A. pulleys B. columns
- He always ……………………………….. the problems and inconveniences of travel. A. magnifies B. sparks
- The college ……………………………. medieval times. A. rigs up B. dates from
- The fortifications of the castle were ………………………………… and impenetrable. A. massive B. unconvinced
- It’s your decision – you have to ……………………….. the responsibility if things go wrong. A. bear B. magnify
- When the ……………………. is moving quickly enough, it is freed and the pilot glides on warm air to rise high in the sky. A. column B. glider
- ……………………………… a wall will not solve the problem. A. Putting up B. Dealing with
- The temple’s grand white …………………………. rose conspicuously over the dirty decaying city. A. arches B. gliders
- It would be ………………………… to take an umbrella. A. sensible B. additional
- After the earthquake, the city …………………………………….. a battlefield. A. beared B. resembled
- LUYỆN TẬP
Bài 1:
1.conventional 2. string 3. backed up 4. via 5.posture
- monument 7. drag 8. involves 9. puzzling 10. intrigues
Bài 2:
1.B 2. A 3. B 4. A 5. A
- B 7. A 8. A 9. B 10. A
- B 12. A 13. A 14. B 15.A
- A 17. B 18. A 19. A 20. A
- B
