Now that we have read the passage, underlined or marked key information, made notes in the margins of the text, and analyzed the data in the table, answer the relevant questions from the beginning of the lesson: 1. How many experiments are discussed in the passage? Only one. 2. What is the purpose of the experiment(s)? To compare the efficiency of different methods of meal moth extermination. 3. What are the variables in the experiment? The variables are food, pesticide, bay leaf, time, and the number of moths in a container. 4. Which variables are controlled by the scientist and how? The scientist controls the contents of each container—food, pesticide, bay leaf, and the initial number of moths. 5. Which variables are measured or observed and how? The number of moths in each container is observed over the course of seven days. 6. Were any calculations performed? No calculations were performed. 7. Is there an experimental control? If so, what is it? The experimental control is the group of moths (6) in the container where ample food is available, and no pesticide or bay leaf is present. It corresponds to the situation where nothing is being done to eliminate the moth population. You may still not understand all the details of this experiment, but the questions above probably helped you organize the information that was presented to you, and you can now proceed to the more challenging task of interpreting the experiments and the experimental results. Analysis When reading Research Summary passages you will have to think about the following questions: What do the results show? What do they mean? How does the measured or observed variable depend on the controlled variable? Let’s look at the data in Example 1. What can we say about the tabulated information? First, there are two different tables. One is for the data taken using the near-IR laser, and the other for data taken using the green laser. The initial intensities of the two lasers are different, the near-IR has an intensity of 500 units, while the green has an intensity of 400 units, but the initial intensity of each laser does not change. The higher the transmitted intensity, the higher the percent transmitted. In fact, the percent transmitted is the ratio of the – ACT SCIENCE REASONING TEST PRACTICE– 274 transmitted intensity to the initial intensity. The higher the transmitted intensity, the lower the absorbed per- cent. In fact, percent transmitted and the percent absorbed always sum up to 100%, which means that the light is either transmitted by the filter or passed by the filter. Now let’s find the solution to the filter problem. Which filter best satisfies the criteria? Looking back at the criteria, we see that the filter must transmit at least 90% of the green, while transmitting, at most, 5% of the near-IR. Which of the filters satisfy the first requirement? Look at the table that outlines experiments with the green laser. Filters that transmit 90 or more percent of the green are Filter 1 and Filter 3. Do any of these two satisfy the second requirement? Check Filter 1 and Filter 3 transmittance of near-IR light. Filter 1 trans- mits 7%, which is above the criterion, while Filter 3 transmits 3%, passing the both criteria, and making it the filter to use. Drawing Conclusions What conclusions can we draw from the research summary presented in Example 2? When the number of moths in a container is zero, the moths have been exterminated. Three out of the six conditions lead to exter- mination. Groups 1, 4, and 5, exterminated by the end of the 7-day period, all lacked food. The moth popu- lations exposed to pesticide or bay leaf, but given ample food, did not die off by the end of the experiment. We can conclude that the extermination of this particular moth within seven days requires the removal of the food supply. What if you were asked how pesticides and bay leaves affect the moth population? To answer this ques- tion, we could place marks in the table to indicate whether the population increases, decreases, or stays the same as on the previous day. Look at the example marks in the table below; +, -, and = signs were used to mark an increase, decrease, and no change in population from the previous day, respectively. The data points that represent the extermination of a population have been boxed with a thick line. GROUP CONDITIONS NUMBER OF ALIVE ADULT MOTHS Food taken Bay away leaf Pesticide Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 1 YES NO NO 10 8 - 3 - 1 - 3 + 0 - 0 = 2 NO NO YES 10 6 - 5 - 3 - 6 + 8 + 9 + 3 NO YES NO 10 8 - 8 = 7 - 8 + 7 - 6 - 4 YES NO YES 10 6 - 3 - 1 - 1 = 0 - 0 = 5 YES YES NO 10 8 - 3 - 1 - 0 - 0 = 0 = 6 NO NO NO 10 10 = 10 = 10 = 12 + 12 + 12 + – ACT SCIENCE REASONING TEST PRACTICE– 275 In experimental science, it is always important not to change too many variables at the same time. If too many variables change, it is difficult to attribute the change in the measured or observed variable to any one variable. When analyzing experimental data, it is also important to compare data sets that are closely related. For example, it wouldn’t make much sense to compare Group 3, provided with ample food and exposed to bay leaf, with Group 4, exposed to pesticide and not provided with food. Making Predictions To truly understand something means to be able to predict it. Here is a prediction question: 1. According to the data collected in Example 2, which of the following strategies would be most effective if the object was to reduce the number of moths as quickly as possible and to completely exterminate them as quickly as possible, without excessive exposure to pesticide? a. Remove all accessible food, spray pesticide every day. b. Spray pesticide every other day and lay out bay leaf around the kitchen. c. Remove all food, lay out bay leaf around the kitchen, and spray pesticide only on the first day. d. Remove all food, and lay out bay leaves on the fourth day. The correct answer is c. The data show the effect of each variable independently. You are asked to inte- grate all the variables to produce the desired change (quick decrease in the number of moths and quick exter- mination without excessive use of pesticide). Food removal is essential, since as data show, as long as food is present, the moth population can be sustained. Bay leaf helps reduce the moth population slightly and steadily and it has an effect on the new moth generation (after day 5, it keeps reducing the number of moths). So bay leaf should be used. Pesticide, however, most dramatically reduces the population when it is originally applied. Since quick reduction of the moth population is required in addition to the extermination, pesticide should be applied the first day. In order to make a prediction, you will need to consider all the information provided. Summary In this lesson you learned to recognize the important elements of an experiment. You also learned to analyze experimental data, draw conclusions, and make predictions based on the experimental information. Remember, research summary passages are often a combination of data representation passages and reading passages. Use the skills you developed for the Reading Comprehension section, as well as the Data Representation lesson when answering research summary questions, and make sure to get as much practice as you can. CONFLICTING VIEWPOINTS This lesson will help you develop skills that you can use to score well on the Conflicting Viewpoints passages on the ACT Science Reasoning Test. These include: understanding the question posed at the beginning of the sample, quickly locating the pertinent detail information in the text, and choosing the best answer. You will – ACT SCIENCE REASONING TEST PRACTICE– 276 also learn to read and understand facts and opinions, as well as recognize, understand, analyze and compare alternative hypotheses or views in order to draw conclusions about the information provided. Reading with Understanding Conflicting Viewpoints passages are two or more separate passages from different scientists, on the same or related topic. Each passage includes both opinions and facts. In this section, you will learn to focus on what is important in such passages to increase your overall understanding of the passage. As a start, take a look at the following example. Is a Vegetarian Diet Healthier? Article 1: Health Benefits of Vegetarian Diets A vegetarian diet offers a wide range of health benefits. Research has shown that vegetarians are less likely to suffer from heart disease, hypertension, obesity, diabetes, certain cancers, gall stones, kidney stones, and osteoporosis. High blood cholesterol is a primary risk factor in cardiovascular disorders, the number one leading cause of death in the United States. Studies found vegetarians to have cholesterol levels 10% lower than health conscious non-vegetarians, which may explain a lower incidence of heart problems among vegetarians. Cancers, such as colon, breast, and prostate, are often diet related. In a study of over 88,000 women 34 to 59 years old, women eating red meat daily ran twice the risk of developing colon can- cer than women eating red meat less than once a month. Reduced incidence of colon cancer in veg- etarians may be attributed to dietary differences that include increased fiber intake, increased consumption of fruit and vegetables, and decreased intake of saturated fat. In addition, 50,000 cases of food poisoning are reported every year and the actual incidence of food poisoning is estimated to be ten times higher. Meat, eggs, and dairy products are the source of 95% of food poisoning. With the benefit of avoiding the diseases linked to meat diets, vegetarianism is clearly the superior choice. Article 2: Health Benefits of Vegetarian Diets Are Not Meat Related There is no evidence that the absence of meat in vegetarian diets is causing the reported reduced health risks in vegetarians. Recent research has demonstrated the importance of antioxidants including beta-carotene and vitamin C and E found in fresh fruit and vegetables. Many researchers now believe that these nutrients, rather than a lack of meat, reduce the risk of heart disease and cancer in vegetarians. Another concern with meat consumption is that antibiotics and other drugs, including steroids and growth hormones, are added to animal feed or injected directly into the animals. Peo- ple who eat meat absorb these drugs into their bodies. Reduced effectiveness of antibiotics for human use may be linked to overuse in animals. – ACT SCIENCE REASONING TEST PRACTICE– 277 Scientists also found that some diseases could be passed from animals to humans through food. Not every piece of meat passes an inspection, and it is possible that meat of a diseased ani- mal ends up in our kitchens. By avoiding meat, vegetarians avoid a potential source of disease. However, that does not mean that a meatless diet is healthier. Meat offers important nutri- ents, including, iron, protein, and vitamin B 12 , which are not easily obtained in vegetarian diets. The benefits of vegetarian diets could be gained just by increasing the fruit, vegetable, and fiber intake, without eliminating meat. The problem with meat isn’t that it’s inherently unhealthy. The problem is the meat industry, which has sacrificed healthy animal conditions, sustainable envi- ronment, and quality control for profits. Vegetarians are avoiding this problem, but they are not fighting it in the most efficient way. A healthy diet should include some healthy meat and we should demand its availability. Getting Started When you are reading the Conflicting Viewpoints passage, make sure you carefully consider the introductory question. It will usually give you some idea of where the conflict is. Reading the introductory passage will give you a frame for the texts that follow it. What could you learn from the introductory passage in the example? ■ The passage is about vegetarian diets. ■ It deals with the impact of a vegetarian diet on health. As you are reading the different viewpoints, keep track of the arguments used to support each viewpoint. In many cases you will be able to pair an argument in one passage with a counterargument in the other. Some- times, the passages will be in agreement except in some sticking point. It is also essential that you understand when a viewpoint is being supported by fact and when by an opinion. Arguments supported by facts are gen- erally considered more convincing. For a discussion on the differences between facts and opinions, read the next section. Facts and Opinions The science community is trained to examine and present facts—data and information that can be tested, observed, and reproduced. Scientists argue against a conflicting viewpoint by presenting conflicting facts. Alternatively, they expose a fault in the facts obtained by those supporting the other viewpoint—for exam- ple, that the facts were obtained under unusual conditions or circumstances. A scientist should be able to repeat the experiment another scientist performed and come up with the same facts. Nonetheless, scientists do have opinions and have a right to express them. It is important to distinguish opinions from facts when reading about different scientific viewpoints. An opinion is a statement not necessarily supported by scientific data. Opinions are often based on per- sonal feelings or beliefs and are usually difficult, if not impossible, to measure and test. Remember that your agreement with a stated opinion does not turn that opinion into a fact. Here is a list of opinions: – ACT SCIENCE REASONING TEST PRACTICE– 278 ■ London weather is beautiful. ■ The grass is always greener on the other side of the fence. ■ Auckland should be the capital of New Zealand. Can you come up with a list of opinions from the example passage? After you write your own, look at the list below. ■ Vegetarianism is clearly the superior choice. ■ The problem is the meat industry, which has sacrificed healthy animal conditions, sustainable environ- ment, and quality control for profits. ■ Vegetarians are avoiding this problem, but they are not fighting it in the most efficient way. ■ A healthy diet should include healthy meat, and we should demand its availability. A fact is a statement based on scientific data or objective observations. Facts can be measured or observed, tested and reproduced. Here are some facts: ■ It rains often in London. ■ Grass in the majority of North American backyards is green. ■ Wellington is the capital of New Zealand. Can you come up with a list of facts from the passage? Here are a few: ■ Research has shown that vegetarians are less likely to suffer from heart disease, hypertension, obesity, diabetes, certain cancers, gall stones, kidney stones, and osteoporosis. ■ In a study of over 88,000 women 34 to 59 years old, women eating red meat daily ran twice the risk of developing colon cancer than women eating red meat less than once a month. ■ Meat, eggs, and dairy products are the source of 95% of food poisoning. ■ Recent research has demonstrated the importance of antioxidants including beta-carotene and vitamin C and E found in fresh fruit and vegetables. ■ Meat offers important nutrients, including, iron, protein, and vitamin B 12 . Let’s match up the arguments presented in the two conflicting viewpoints. 1. Article 1 says vegetarian diets are healthier. Article 2 says this is due to increased fruit and vegetable intake. 2. Article 1 says that animal products are the source of most food poisonings. Article 2 says that this is due to poor quality control, rather than the inherent nature of meat. – ACT SCIENCE REASONING TEST PRACTICE– 279 . 7 1 YES NO NO 10 8 - 3 - 1 - 3 + 0 - 0 = 2 NO NO YES 10 6 - 5 - 3 - 6 + 8 + 9 + 3 NO YES NO 10 8 - 8 = 7 - 8 + 7 - 6 - 4 YES NO YES 10 6 - 3 - 1 - 1 = 0 - 0 = 5 YES YES NO 10 8 - 3 - 1 - 0 - 0. passages are often a combination of data representation passages and reading passages. Use the skills you developed for the Reading Comprehension section, as well as the Data Representation lesson. to read and understand facts and opinions, as well as recognize, understand, analyze and compare alternative hypotheses or views in order to draw conclusions about the information provided. Reading