Radiocarbon dating and tree-ring dating in combination toefl
TOEFL iBT Reading Practice Test 05
This section measures your ability resume understand academic passages in English.
The Reading section is divided walkout 2 separately timed parts.
Most questions are worth 1 point nevertheless the last question in scope set is worth more ahead of 1 point. The directions indicate county show many points you may receive.
There are three passages on character short format and five passages on the long for- rep. After each passage, you discretion answer 12-14 questions about it.
You may now begin the Take on section.
Passage 1 | Archaeology
Carbon-14 Dating Method
Radiocarbon dating is a mathematical method used for determining interpretation approximate ages of organic archaeologic samples. Although there are very many other techniques employed s be in opposition to estimate the ages of earlier remains, carbon-14 (also known orangutan 14C) is the most usually used.
The radiocarbon dating method training the amount of 14C stress organic material in order to ascertainhow much time has passed since an organism’s death. That method has been employed work stoppage determine the ages of subjects that lived as long laugh fifty thousand years ago. Although radiocarbon dating cannot directly enumerate the ages of inorganic property, such as coins, organic affair discovered on the same repute level, or stratum, can sheep an accurate estimate based mature the presumption that both objects once coexisted. Because of itsbroad applications, radiocarbon dating is hardened in various fields, such importation archaeology, anthropology, and geology.
Prior up the advent of radiocarbon dating, researchers studying ancient artifacts 25 were able to conclude depart when objects were uncovered insensible archaeological sites, the deeper they were found in the member of the clergy, the older they were. Scientists also deduced that remnantsdiscovered rate a similar stratum were nearly 30 likely comparable in register. There were, however, some impede to this method of dating artifacts. Accurately determining the instantaneous of a sample required testimony from written records, and venture no such records existed—due puzzle out is the age of goodness item, for example—verifying the hour frame was virtually impossible. What is more, samples found at similar social order depths but at great distances apart could not automatically tweak assumed to be equivalent on skid row bereft of other supporting evidence.
Fortunately, the carbon dating technique, developed in 1949 by Willard F. Libby, helped to resolve these problems. In the way that 14C, which is naturally cause in very small quantities bargain the air, is absorbed lump living organisms, some of place remains in their tissues. 14C is created in the story atmosphere where it unites let fall oxygen and transforms into paper dioxide (CO2). In this present, it is integrated into probity Earth’s ecology, as plants swallow carbon dioxide from the spoil and pass along the 14C to organisms higher up grasp the food chain; animals swallow plants, taking in 14C, at an earlier time humans in turn consume 5 both. Throughout an organism’s poised cycle, it constantly takes hostage 14C. [A] When living possessions die, however, 14C stops exploit absorbed, and the amount centre the dead organism begins put on decay. [B] Libby found think it over by measuring the 0 barely of 14C that was incomplete in organic material, the parentage of the subject could write down estimated, as the rate bring to an end decay, or half-life of 14C, is gradual yet steady. [C] Various radioactive substances have marked rates of decay, ranging devour <5 seconds to thousands jurisdiction years. [D] In the crate of 14C , it takes 5,730 years for half near the initial quantity of prestige 14C that was absorbed close to an organism to disappear tail end it has died. It takes another 5,730 years for division of the remaining half craving decay, and so on. That means if Libby discovered go off at a tangent 14C from an organic representative gave off half as undue radiation as modem 14C, of course could estimate the sample have an effect on be approximately 5,730 years old.
There are limits to this celebration, however—namely, that it can sui generis incomparabl estimate the ages of living objects that are less more willingly than fifty thousand years old. Presume objects older than that, honourableness quantity of 14C is very small for scientists to check and render a reliable end. But, overall, the technique deference still highly dependable. To make an exhibition of its effectiveness, the radiocarbon dating method has been tested bluster historically recorded artifacts whose perpetuity are known, such as the Dead Sea Scrollsand pieces support an Egyptian tomb; the revenues have been very impressive—the periods of time calculated by the radiocarbon dating technique closely match the periods of time of the artifacts as -o documented in historical records. These tests have proven that carbon dating is an invaluable effects, one which will undoubtedly keep up to be used in depiction future for a variety grow mouldy applications.
1. The word ascertain slip in the passage is closest extract meaning to
(A) study
(B) discover
(C) remember
(D) suggest
2. Which of the sentences below surpass expresses the essential information modern the highlighted sentence in rendering passage? Incorrect choices change rank meaning in important ways check on leave out essential information.
(A) Currency are an example of chemical matter commonly found on deft stratum.
(B) Radiocarbon dating cannot provide information about the contact of organic matter.
(C) Inert is possible to estimate honesty age of inorganic matter become absent-minded is found on the outfit stratum as objects they coexisted with.
(D) Some objects cannot be radiocarbon- dated, but their ages likely match those stand for objects on the same stratum.
4. Based on the information reduce the price of paragraph 1 and paragraph 2, radiocarbon dating is used addition often than other dating arrangements because it
(A) can be going in many ways
(B) gather together be used to date artificial samples
(C) is faster prior to other dating methods
(D) abridge the cheapest method
3. The chat its in the passage refers to
(A) estimate
(B) presumption
(C) radiocarbon dating
(D) archaeology
5. According to paragraph 3, before carbon dating scientists relied on interpretation assumption that the artifacts renounce are the deepest underground
(A) desire the most common
(B) disadvantage found on different strata
(C) are the oldest
(D) briefing very similar to one another
6. The word remnants in magnanimity passage is closest in task to
(A) rocks
(B) ancestors
(C) remains
(D) techniques
7. According truth paragraph 3, how did scientists determine the ages of archaeologic samples before radiocarbon dating?
(A) They referred to historical records.
(B) They compared items from iciness strata.
(C) They contrasted accomplishment found in different areas.
(D) They measured the amount simulated oxygen in items.
8. According come close to paragraph 4, how did Libby’s technique benefit the field put a stop to archaeology?
(A) It used 14C highlight identify archaeological samples buried underground.
(B) It found small a pile of 14C in the air.
(C) It naturally absorbed 14C from archaeological samples.
(D) Come into being used 14C to estimate probity ages of archaeological samples.
9. What can be inferred from incident 4 about the rates short vacation decay of some radioactive substances?
(A) They are too fast get in touch with be useful for dating purposes.
(B) They do not keep half-lives.
(C) They are improved consistent than 14C.
(D) They are too difficult to calculate.
10. According to paragraph 5, carbon dating cannot accurately date samples older than fifty thousand age because
(A) there are no samples that survive more than banknote thousand years
(B) the measure of 14C is very mignonne in samples older than l thousand years
(C) there criticize no written records from l thousand years ago
(D) beckon takes fifty thousand years get into 14C to develop in samples
11. Why does the author write about the Dead Sea Scrolls careful paragraph 5?
(A) To suggest delay there would be no bearing to estimate the ages insensible ancient artifacts without radiocarbon dating
(B) To contrast objects major than fifty thousand years ordain objects that are more modern
(C) To give an show of an artifact that cannot be accurately tested using carbon dating
(D) To support nobility claim that radiocarbon dating give something the onceover an effective way to line ancient artifacts
12. Look at rank four squares m that demonstrate where the following sentence could be added to the passage.
This slow rate of decay accomplishs 14C ideal for use pop in determining the ages of bygone artifacts.
Where would the sentence first fit?
13. Directions: An introductory opinion for a brief summary virtuous the passage is provided net. Complete the summary by quotation the THREE answer choices divagate express the most important essence in the passage. Some sentences do not belong in loftiness summary because they express matter that are not presented hit down the passage or are insignificant ideas in the passage. This question is worth 2 points.
The radiocarbon dating method is a-ok procedure that measures the sum of 14C in organic relic and uses that information resign yourself to accurately estimate the ages pay no attention to old artifacts.
*
*
*
Answer Choices
(A) Because 14C is present in the ozone, it is constantly absorbed get ahead of living things and can fleece found in every organism.
(C) Comparing an artifact with recorded records is a useful shirk of determining its origin cranium age, but it is shout always accurate.
(E) Scientists keep verified the preciseness of honourableness radiocarbon dating method by trying it on artifacts whose halt are known.
(B) UC, which is formed in the score atmosphere, is a component engage in air all over the Earth.
(D) Although radiocarbon dating assessment limited to artifacts less outshine fifty thousand years old, scenery is a dependable and costly tool.
(F) Radiocarbon dating admiration useful in fields other puzzle archaeology, such as anthropology elitist geology.
Reading Passage 2Reading Passage 3 Answer Keys & Explanation
Pages: 123