Physical Science End of Chapter Question Chapter 1 Page 36-37 1. Everday Words Used in Science In everday speech, the words precision and accuracy are often used interchangeably. When these terms are used in science, are their meanings the same as their everyday meanings? Precision is the exactness of an answer while accuracy is a description of how close a measurement is to the true value of a measurement. Using Key Terms 2. Physical Science was once defined as “the science of the nonliving world.” Explain why that definition is no longer sufficient. Today we tie in Physical Science with Chemistry and Biology, called Biochemistry. It is not just the nonliving world. 3. Explain why the observation that the sun sets in the west could be called a scientific law. Repeatedly day after day it does, so it is a law. 4. Explain why the following statement could be considered a scientific theory: The rotation of Earth causes the sun to set. It is a tested possible explanation of why the sun sets in the west. 5. What is mass, and how does it differ from weight? Mass is a quantity of matter, weight is a force that the Earth’s gravity pulls on the matter. 6. Some features on computer chips can be as small as 35 nm. Explain why you would use scientific notation to express this quantity in meters. It would be used because there would decrease the number of zeros. 7. The mass of a certain elephant is 3,476 kg. A zoologist who measures the mass of that elephant finds that the mass is 3,480 kg. Is the mass measured by the zoologist accurate? The mass is accurate because it is very close to the very actual weight of the elephant. Understanding Key Ideas 8. Which branch of science is not included in physical science? D. zoology 9. Which science deals most with energy and forces? B. physics 10. Using superconductors to build computers is an example of A. technology 11. A balance is a scientific tool used to measure D. mass 12. Which unit is an SI base unit? C. kilogram 1 Physical Science End of Chapter Question Chapter 1 Page 36-37 13. The composition of the mixture of gases that makes up our air is best represented on what kind of graph? A. pie graph 14. In a controlled experiment C. you change one variable throughout the experiment, and the other variables remain fixed. 15. Written in scientific notation, 0.000060 x is B. 6.0 x 10-5 s 16. When studying a molecule, a chemist might make a model of the molecule to B. help visualize the molecule 17. The maximum depth of a certain lade is 244 m. What is the depth of the lake in kilometers? B. 0.244 km Explaining Key Ideas 18. Do scientific laws ever change? Explain. Yes they can change if a new discovery cannot be predicted by a repeated experiments then the law may need to be modified to explain the new discovery. 19. Explain whether or not scientific methods are sets of procedures that scientists follow. They are not exact sets of procedures, they are only guidelines. 20. Which variable is the dependent variable, and which variable is the independent variable? Dependent variable: temperature Independent variable: time 21. Why as this data presented in a line graph? Because the temperature changed continuously with time during the experiment. Critical Thinking 22. Applying Ideas Today, scientists must search through scientific journals before performing an experiment or making methodical observations. Where would this step take place in a diagram of scientific methods? Research and Data Collection step. 23. Evaluating Assumptions At an air show, you are watching a group of sky divers when a friend says, “We learned in science class that things fall to Earth because of the law of gravitation.” What is wrong with your friend’s statement? Explain your reasoning. The law of gravitation states that objects fall to the Earth and how to calculate, but it does not explain WHY. 2 Physical Science End of Chapter Question Chapter 1 Page 36-37 24. Applying Concepts You report that a friend can go exactly 500 m on a bicycle in 39.46 s. But your stopwatch runs 2 s fast. Explain how your stopwatch affects the accuracy and precision of your measurement. Because your stopwatch runs fast the time you measure is not accurate. However your watch can measure somewhat precise. 25. Bar Graphs The bar graph below summarizes how a consumer magazine has rated several stereos by price and sound quality. Use the graph to answer the following questions. a. Which brand do you think has the best sound for the price? Walsonic has the sound for the best price. b. Do you think that sound quality is truly related to price? Explain your answer. If sound quality and price were equal for all of the companies then sound quality and price would be related. The graph shows that these two properties change relative to one another depending on the company; so sound quality and price are not truly related. 26. Pie Graph The composition of silver solder is 40% silver, 40% tin, 14% copper, and 6% zinc. Show this composition in a pie graph. 40 40 14 6 27. Writing Scientific Notation Write the following measurements in scientific notation. a. 22,000 mg 2.2 x 104 mg b. 0.0000037 kg 3.7 x 10-6 kg 28. Using Scientific Notation Write the answers to the following calculations in scientific notation. a. 37,000,000 A x 7,100,000 s 2.6 x 1014As 3 Physical Science End of Chapter Question Chapter 1 Page 36-37 b. 0.000312 m3 / 486 s 6.42 x 10-7 m3/s 29. Significant Figures Round the following measurements to the number of significant figures shown in parentheses. a. 7.376 m (2) 7.4 m b. 362.00306 s (5) 362.00 s 30. Significant Figures Write the answers to the following calculations. Be sure to use the correct number of significant figures. a. 15.75 m x 8.45 m 133 m2 b. 5,650 L / 27 min 210 L/min 4