1.2 What is Science? Review Questions and Answers
- Explain why science is considered both a process and a body of knowledge. Science is a body of knowledge, but it is also the process by which this knowledge is obtained. Scientific knowledge advances over time with repeated experimentation and testing.
- State three specific examples of human endeavors that are based on scientific knowledge. Answers will vary. Sample answer: Three specific examples of human endeavors that are based on scientific knowledge are determining the cause of a disease such as Alzheimer’s disease, designing a building that can resist the shaking of a strong earthquake without collapsing, and developing the technology needed to send astronauts to Mars.
- How does science influence your daily life? Answers will vary. Sample answer. In my daily life I take medication to treat a medical condition, ride a bus, and use computers and other technology. Science was necessary to develop all of these things.
- Jenner used a young boy as a research subject in his smallpox vaccine research. Today, scientists must follow strict guidelines when using human subjects in their research. What unique concerns do you think might arise when human beings are used as research subjects? Sample answer: Using human beings as research subjects might raise concerns about risk of physical harm to the subjects or privacy issues. These concerns would not arise in research on most other organisms.
- What gave Jenner the idea to develop a vaccine for smallpox? Jenner observed that people who became infected with cowpox did not get sick from smallpox.
- Why do you think almost a century passed between the development of the first vaccine (for smallpox) and the development of the next vaccine (for cholera) The fact that “germs” can cause disease was not known until around the time the cholera vaccine was developed. Jenner made the lucky observation earlier that people who were infected with cowpox did not get sick from smallpox, but it is relatively rare to find similar diseases where one naturally confers immunity to the other.
1.3 The Nature of Science: Review Questions and Answers
- Define science. Science is a distinctive way of gaining knowledge about the natural world that tries to answer questions with evidence and logic.
- What is the general goal of science? The general goal of science is to increase our knowledge of nature.
- Identify four basic assumptions that scientists make when they study the natural world. Four basic assumptions that scientists make are: nature can be understood through systematic study, scientific ideas are open to revision, sound scientific ideas withstand the test of time, and science cannot provide answers to all questions.
- Do observations in science have to be made by the naked eye? Can you think of a way in which scientists might be able to make observations about something they cannot directly see? Observations in science do not need to be made by the naked eye. Scientists can use tools to make observations about nature that are not observable directly by the human senses. Answers may vary. Examples may include the use of a microscope, telescope, unmanned space vehicle, etc.
- If something cannot be observed, can it be tested scientifically? Explain your reasoning. No. Science relies on evidence, and if something cannot be observed, evidence cannot be gathered.
- Scientific knowledge builds upon itself. Give an example of a scientific idea from the reading where the initial idea developed further as science advanced. Answers may vary. Mendel’s laws of inheritance and Dalton’s atomic theory are some possible answers.
- Discuss this statement: “Scientific ideas are always changing, so they can’t be trusted.” Do you think this is true? While it is true that scientific ideas are open to change, scientific findings that have been repeatedly replicated and supported by different lines of evidence can be trusted to be likely to be accurate. Newer ideas that have not been as thoroughly tested, however, may be viewed with some skepticism until more evidence is obtained.
- Why do you think that scientific knowledge expands as technology becomes more advanced? As technology advances, scientific instruments and tools improve, which increases our ability to do experiments and make observations about the natural world.
1.4 Scientific Investigations: Review Questions and Answers
1.5 Theories in Science: Review Questions and Answers
- Define scientific theory. A scientific theory is a broad explanation that is widely accepted because it is strongly supported by a great deal of evidence.
- Compare the way the word theory is used in science versus in everyday language. In everyday language, the word theory is used to refer to a guess or a hunch that may or may not be true. In science, the word theory is used to refer to an idea that is widely accepted because a great deal of evidence has accumulated in support of it.
- What is the germ theory of disease? How did it develop? The germ theory of disease is the idea that contagious diseases are caused by “germs,” or microorganisms. The idea that tiny “seedlike entities” (or germs) cause disease was first introduced by Fracastoro in the mid-1500s, but it was largely ignored. However, over the next three centuries, evidence accumulated to support the fledgling theory. For example, van Leeuwenhoek used the microscope to discover microorganisms such as bacteria in the 1600s. In the mid-1800s, Semmelweis used hospital data to infer that germs transmitted on doctors’ unwashed hands spread puerperal fever. Unfortunately, his evidence was derided. In the 1860s and 1870s, Pasteur conducted careful experiments and found convincing evidence that microorganisms cause certain diseases, including puerperal fever. Pasteur’s evidence and strong conviction about germ theory allowed him to convince the scientific community to accept the theory.
- Explain why Pasteur, rather than Fracastoro or Semmelweis, is called the father of germ theory. Although Fracastoro made the first clear statement of germ theory and Semmelweis provided some evidence for it, neither of them convinced other physicians or scientists to accept the theory. Pasteur is called the father of germ theory because he undertook careful experiments that provided strong evidence for germ theory and also convinced most of the scientific community to accept it.
- Galen and Fracastoro may have come up with different explanations for how disease is spread, but what observations do you think they made that were similar? Galen and Fracastoro both probably observed that people became sick by being near sick people or dead bodies. This led Galen to propose miasma as the disease-causing agent, but Fracastoro ascribed the cause to “seed-like entities.”
- Use the explanation of Semmelweis’ research and the graph in Figure 1.9 to answer the following questions:
- What was Semmelweis’ observation that led him to undertake this study? What question was he trying to answer? Semmelweis had observed that maternal deaths from puerperal fever occurred much more often when women gave birth at his hospital than at home. He wanted to know why this was occurring.
- What was the hypothesis (i.e. proposed answer for a scientific question) that Semmelweis was testing? Semmelweis’ hypothesis was that puerperal fever was a contagious disease caused by some type of matter carried to pregnant patients on the hands of doctors from autopsied bodies.
- Why did Semmelweis track death rates from puerperal fever at Dublin Maternity Hospital, where autopsies were not performed? Semmelweis used data from Dublin Maternity Hospital where autopsies were not performed so he could test his hypothesis that it was an agent transferred on the hands of physicians from autopsied bodies that was causing women to die more frequently of puerperal fever. Dublin Maternity Hospital served as a control so that Semmelweis could compare death rates between a hospital that did not perform autopsies to one that did, which helped point to autopsies as a causative factor.
- What were two pieces of evidence shown in the graph that supported Semmelweis’ hypothesis? Two pieces of evidence that supported the idea that physicians were transferring contagious material from autopsies to women giving birth were: 1) the death rate from puerperal fever increased after autopsies started being performed, and 2) the death rate from puerperal fever went back down after hand washing was implemented.
- Why do you think it was important that Semmelweis compared Dublin Maternity Hospital and Wien Maternity Clinic over the same years? It was important that Semmelweis compared Dublin Maternity Hospital and Wien Maternity Clinic over the same years because puerperal mortality rates fluctuated slightly year by year. There may have been other factors that affected death rate in a given year, so in order to isolate the variable he wanted to test (i.e. autopsies), he needed to compare the two hospitals in the same years.
- What is the difference between a microorganism and a pathogen?Microorganisms are any organism too small to be seen without magnification. Pathogens are specific types of microorganisms that cause disease.
- Explain why the development of the microscope lent support to the germ theory of disease. Because specific microorganisms and germs could finally be seen and identified with the microscope.
- Does the observation of microorganisms alone conclusively prove that germ theory is correct? Why or why not? Simply observing microorganisms does not conclusively prove that germ theory is correct. It was a first step and showed that microorganisms exist, but scientists also had to prove that microorganisms can be transferred from person to person and cause disease in order to support the validity of germ theory.
- Who do you think was using more scientific reasoning: Semmelweis or the physicians that derided his results? Explain your answer. Semmelweis used scientific reasoning because he carefully collected and analyzed data, appropriately tested his hypothesis, and drew his conclusions from multiple pieces of evidence. The physicians that derided his results, however, did not gather evidence and simply went on the assumption that physicians are always clean. Therefore, they were not scientific in their reasoning.
1.6 Traditional Ecological Knowledge: Review Questions and Answers
- Define Traditional Ecological Knowledge. Answers will vary. Sample answer: TEK is the knowledge base acquired by Indigenous and local people over hundreds or thousands of years through direct contact with the environment. It includes intimate and detailed knowledge of plants, animals and natural phenomena the development and use of appropriate technologies for hunting, fishing, trapping, agriculture, and forestry and a holistic knowledge or worldview which parallels the scientific disciplines of ecology.
- How is TEK passed down through generations? TEK is passed down through generations by storytelling, direct teaching from elders to young generation through mentorship.
- How does TEK differ from Western Science? In TEK, knowledge is passed on orally, partly through metaphor and story, and this learned knowledge is embedded into daily living. TEK also differs from Western Science in that TEK is tied in to morality, spirituality and individual identity, making it more than just knowledge; it is sacred knowledge.
- What are some ways in which TEK can inform resource management? TEK is a vast body of knowledge which spans extremely long periods of time. It can be used to predict and identify changes or cycles in plant and animal life, as well as large-scale changes in climate or landscape.
- What are some of the ramifications of loss of TEK? How can TEK be maintained? TEK is the culmination of millennia of shared knowledge specific to an area or region. There are no other people groups with such detailed and long-term knowledge of their place. TEK can be maintained by connecting with Elders in Indigenous communities and participating in storytelling and mentorship.
1.7 Pseudoscience and Other Misuses of Science: Review Questions and Answers
- Define pseudoscience. Give three examples. Pseudoscience is a claim, belief, or practice that is presented as scientific but does not adhere to the standards and methods of science. Unlike true science, pseudoscience is not based on repeated evidence gathering and testing of falsifiable hypotheses. Three examples of pseudoscience are phrenology, astrology, and numerology.
- What are some indicators that a claim, belief, or practice might be pseudoscience rather than true science? Sample answer: Some indicators that a claim or idea might be pseudoscience rather than true science: a claim is vague or exaggerated, an idea is assumed to be true unless proven otherwise, an idea is expressed in scientific-sounding language to make it sound scientific when it is not.
- Astrology was once considered a science, and it was common in academic circles. Why did its status change from a science to a pseudoscience? With the advent of modern Western science, astrology was called into question. It was challenged and tested on both theoretical and experimental grounds. Eventually, it was shown to have no scientific validity or explanatory power.
- What are possible reasons that some pseudosciences remain popular even after they have been shown to have no scientific validity or explanatory power? Sample answer: The persistent popularity of some pseudosciences suggests a lack of scientific literacy in the general public. For example, astrology has long been known to have no scientific validity or explanatory power, yet it is still thought to be scientific by a third of Americans. This suggests that many Americans lack a correct understanding of scientific principles and methods.
- List three other ways besides pseudoscience that science can be misused, and identify an example of each. Besides pseudoscience, science can be misused by hoaxes, frauds, and fallacies. An example of a scientific hoax is Piltdown man. Wakefield’s 1998 MMR vaccine-autism article is an example of a scientific fraud. The idea that correlation implies causation is a scientific fallacy.
- Explain how misuses of science may waste money and effort. How can they potentially cause harm to the public? Misuses of science may waste money and effort by leading scientists to pursue blind alleys. For example, Piltdown man confused and misdirected the study of human evolution for decades. Actual fossils of early humans were ignored because they didn’t support the Piltdown paradigm. Misuses of science may harm the public by spreading dangerous misinformation. For example, Wakefield’s vaccine-autism fraud made parents afraid to have their children vaccinated. Lower vaccination rates put hundreds of thousands of children at risk of potentially fatal diseases.
- Many claims made by pseudoscience cannot be tested with evidence. From a scientific perspective, why is it important that claims be testable? Claims must be testable in science because otherwise there is no way to determine whether they are accurate.
- What do you think is the difference between pseudoscience and belief? Answers may vary. Sample answer: Beliefs do not necessarily claim to have a scientific basis, while pseudoscience does.
- If you see a website that claims an herbal supplement causes weight loss and they use a lot of scientific terms to explain how it works, can you be assured that the drug is scientifically proven to work? If not, what are some steps you can take to determine whether or not the drug does in fact work? Answers may vary. Sample answer: No, it does not necessarily mean the original research was fraudulent, although it could be. It depends on the circumstances. If the researchers were found to have actively altered or made up the data, it is certainly fraudulent. However, the process of science involves repeated evidence gathering, and with extended and repeated testing, new findings may come to light that change the original interpretations of the data. Also, the original experiments may have had an unknown source of error, but that is different from being intentionally fraudulent.
- Why do you think it was problematic that Andrew Wakefield received funding from a group of people who were suing vaccine manufacturers? It was problematic that Andrew Wakefield received funding from a group of people who were suing vaccine manufacturers because it is a potential conflict of interest. He had a vested financial interest in claiming that vaccines cause harm, which may have contributed to him writing a fraudulent paper.
- What do you think it says about the 1998 Wakefield paper that ten of the 12 coauthors formally retracted their conclusions? Answers may vary. Sample answer: I think that the vast majority of the co-authors retracting their conclusions lends support to the idea that the research was fraudulent. These co-authors may or may not have been aware of that originally, but they did not stand by the paper when allegations of fraud came to light.
Chapter 1 Case Study Conclusion: Review Questions and Answers
- Why does a good hypothesis have to be falsifiable? A good hypothesis is falsifiable because scientists need to be able to reject it if it is not true.
- Name one scientific law. Answers will vary. Sample answer: Mendel’s laws of inheritance.
- Name one scientific theory. Answers will vary. Sample answer: The theory of evolution or the germ theory of disease.
- Give an example of a scientific idea that was later discredited. Answers will vary but could include Andrew Wakefield’s assertion that the MMR vaccine causes autism or Galen’s idea that “miasma” spreads disease.
- A statistical measurement called a P-value is often used in science to determine whether or not a difference between two groups is actually significant or simply due to chance. A P-value of 0.03 means that there is a 3% chance that the difference is due to chance alone. Do you think a P-value of 0.03 would indicate that the difference is likely to be significant? Why or why not? This is likely to be significant because there is only a 3% probability that the difference is due to random chance, and therefore a 97% probability that it is actually significant.
- Why is it important that scientists communicate their findings to others? How do they usually do this? It is important that scientists communicate their findings to others so that they can be replicated. If they cannot be replicated, their findings are not likely to be accurate. Also, science builds upon prior scientific knowledge, so it is important to share results so that science can advance. Scientists publish their results in peer-reviewed scientific journals.
- What is a “control group” in science? A control group is the comparison group against which the manipulated (experimental) group is compared in order to observe the effect of the variable of interest.
- In a scientific experiment, why is it important to only change one variable at a time? It is important to change only one variable at a time because if you change multiple variables, you won’t know which one is responsible for causing the observed outcomes
- Which is the dependent variable – the variable that is manipulated or the variable that is being affected by the change? The variable that is affected by the change.
- You see an ad for a “miracle supplement” called NQP3 that claims the supplement will reduce belly fat. They say it works by reducing the hormone cortisol and by providing your body with missing unspecified “nutrients”, but they do not cite any peer-reviewed clinical studies. They show photographs of three people who appear slimmer after taking the product. A board-certified plastic surgeon endorses the product on television. Answer the following questions about this product.
a. Do you think that because a doctor endorsed the product, it really works? Explain your answer. Not necessarily. For one, the doctor is a plastic surgeon, so she or he is not necessarily an expert in weight loss or nutrition. Second, you do not know if the doctor was compensated for their endorsement, so they may have a financial interest in saying that the product works. Third, endorsement by a medical professional alone doesn’t ensure that the product works – the product must be tested using the scientific process.
b. What are two signs that these claims could actually be pseudoscience instead of true science? Answers may vary, but might include: over-exaggeration of claims (calling it a “miracle”), using scientific terms, being vague (unspecified “nutrients”), and lack of peer-reviewed studies.
c. Do you think the photographs are good evidence that the product works? Why or why not? No. Reasons will vary. Sample answer: Photographs can be manipulated using software, the sample size is very small, and this was not a peer-reviewed scientific study so you don’t know whether the supplement was the only variable changing in the before and after scenarios.
d. If you wanted to do a strong scientific study of whether this supplement does what it claims, what would you do? Be specific about the subjects, data collected, how you would control variables, and how you would analyze the data. Answers will vary. Sample answer: I would select well-matched control subjects and collect initial data on their weight, waist size, diet, and exercise levels. Then I would give half of the subjects the supplement, and the other half a placebo. This would be a double-blind experiment, so both the subjects and the researchers would not know which groups the subjects were in. Subjects would be instructed to not change any other variable of their lifestyle, such as diet or exercise. After two months, I would take the same measurements again and do inferential statistics to determine whether there is a significant difference between the supplement group compared to the placebo (control) group.
e. What are some ways that you would ensure that the subjects in your experiment in part d are treated ethically and according to human subjects protections regulations? I would make sure that all participants are fully informed of: the purpose of the experiment, any risks associated with the experiment, that they can withdraw at any time, and that they are participating voluntarily.