Chem;Writing and Doing Science

1 Reading, Writing and Doing ScienceLearning ObjectivesAs you work through this chapter you will learn how to:< identify and apply the elements of the scientific method.< distinguish between science and pseudoscience.< plan a scientific experiment.< identify quantitative relationships between two quantities.< graph quantitative data on an x-y scatter plot. y1 and x2 > x1) and the line slopes upward as yougo from left to right. The line will slope downward as you go from left to right if theslope is negative. It is quite convenient to use various computer programs to generate28 CHAPTER 1 READING, WRITING AND DOING SCIENCEgraphs and the lines that fit the plotted data. A spreadsheet program such as MicrosoftExcel can be used to make simple x-y scatter plots.Check for Understanding 1.3 Solutions1. The equation for the straight-line graph in Figure 1.5 is y = 0.0038x – 0.047.Determine the Kelvin temperature (K) at which the pressure of this gassample equals 0.94 atm.2. Imagine doing an experiment in which you burn a candle and measure itsdiminishing mass at various times.a) If you plot candle mass (in grams) on the y-axis and time (in minutes)on the x-axis and fit the data with a straight line, what are the units forthe slope of this line?b) Do you expect the slope of this straight line to be positive ornegative? Explain your answer.CHAPTER 1 READING, WRITING AND DOING SCIENCE 29Chapter 1 Keywords Glossaryscientific theory experimentation ideal gasmass scientific law directly proportionalweight scientific principle independent variablecore ideas of science scientific rule dependent variablefrontiers of science control experiment x-y scatter plotfringe ideas experimental variables x-axisscientific method pseudoscience y-axisobservations alternative science inversely proportionalhypothesis quantitative results slope of the linepredictions qualitative results y-axis interceptSupplementary Chapter 1 Check for Understanding questionsChapter 1 Exercises Answers1. Do an Internet search for each of the items listed below. Based on thisinformation, determine whether each is part of the core ideas, frontier ideas orfringe ideas in science.a) cold fusionb) quantum electrodynamicsc) homeopathic treatment of flu symptoms (oscillococcinum)d) big bang cosmologye) nuclear fusion reactorsf) link between low-level electromagnetic radiation and leukemia2. What is the difference between a hypothesis and a scientific theory?3. What is the difference between a scientific theory and a scientific law?4. Outline the typical sequence of steps in the scientific method.30 CHAPTER 1 READING, WRITING AND DOING SCIENCE5. Why is it more appropriate for an elementary school student doing a scienceproject to start the scientific process by trying to answer a question rather than byproposing and testing a hypothesis?6. Characterize each of the following as an example of a scientific law, scientifictheory, hypothesis, observation, or none of these.a) an apple a day keeps the doctor awayb) my brother doesnít like to eat saladsc) your cell phone isnít working because the battery must be deadd) breaking a mirror brings seven years of bad lucke) all matter is composed of atoms7. Which of the following is a scientific theory?A. Beethovenís contributions to music would have been greater if he had marriedB. left-handed people are more artistically inclinedC. vitamin C prevents the common coldD. all of the aboveE. none of the above8. Indicate whether each of the following is an example of a scientific law. If anitem isnít a law, identify what it represents.a) like electric charges repelb) particles in the gas phase exert a pressure by colliding with the containerwallsc) metals tend to be good conductors of electricityd) in a chemical reaction, matter is neither created nor destroyede) visible light consists of photons9. Do you agree with the statement: ìAn individual scientist can not propose atheory, only a hypothesis.î? Provide a short justification for your answer.CHAPTER 1 READING, WRITING AND DOING SCIENCE 3110. Five dimes and five pennies are secretly distributed between box A and box B.Then two coins are removed from each box. Two pennies are drawn from box Aand two dimes are drawn from box B. Based on these observations, which of thefollowing may be valid?A. box A contains only penniesB. box B contains both dimes and penniesC. box A contains more dimes than penniesD. all of the aboveE. only A and B11. Briefly describe how to organize an experiment to determine the effect that aparticular variable has on the outcome.12. Suppose you wish to determine the effect of ultraviolet (UV) light exposure on aparticular species of fish.a) Describe a control experiment that you would do.b) Identify the experimental variables that you would control.13. Using Internet resources, decide whether air ionizers really provide effective airpurification or whether this is pseudoscience. Justify your conclusion withspecific information.14. Solve each of the following relationships for y.a) x2 ? y2 ? a ? b b) 45 1 2x 16y? ? ?15. You are asked to make a x-y scatter plot of your height versus your age duringyour lifetime. What variable do you put on the x-axis? Why?32 CHAPTER 1 READING, WRITING AND DOING SCIENCE050010001500200025000 1 2 3 4 5 6 7 8Volume (in3)Mass (g)16. Calculate the slope of the line on the x-y scatter plot below. Be sure to includethe proper units.17. Write a short paragraph in your own words summarizing the key conceptsdiscussed in Section 1.3.