HONORS PHYSICS Introduction

Transcription

1 HONORS PHYSICS Introduction OBJECTIVES: 1. List and describe the steps of the scientific method. 2. Differentiate between independent and dependent variables, controls and constants. 3. Distinguish observations from inferences. 4. Distinguish between quantitative and qualitative measurements. 5. List the basic SI units of measurements. 6. Convert units using conversion factors and the factor label method. 7. Differentiate between fundamental and derived units. 8. Distinguish between precision and accuracy. Give examples 9. Use significant digits correctly when recording data. Be able to perform mathematical calculations using significant digits. 10. Be able to plot data using correct graphing techniques. VOCABULARY: science technology theory law scientific method independent variable dependent variable constant control length mass volume weight scientific notation significant figures accuracy precision SI or metric unit

2 Scientific Method Reviewing vocabulary Match the following vocabulary with the appropriate statement. Each word maybe used once, more than once or not at all. 1. adjusted by the experimenter a. conclusion 2. an educated guess b. constant 3. a fact c. control 4. explains a law d. dependent variable 5. a feature of matter e. experiment 6. applied science f. hypothesis 7. a description of an event in nature g. independent variable 8. used to explain something not easily h. law understood 9. judgment based on interpreting observations i. model 10. a standard used for comparison in an experiment j. observation k. physical science l. property m. technology n. theory Reviewing Concepts Choose the word or phrase that correctly completes each of the following sentences. 11. A hypotheses is tested by a(n) (inference, conclusion, experiment) 12. The standard for comparison in an experiment is called a(n) (control, independent variable, dependent variable). 13. The engineer s guess that the radiation came from his house was a ( model, hypothesis, conclusion) 14. All of the following are examples of matter except (light, air, water, iron) 2

3 Complete each of the following sentences with the correct word or phrase. 15. A guess based on observation is a(n) 16. Physics and physical science is the study of 17. Technology is thought of as science. 18. The conclusion of an experiment is based on the interpretation of. 19. When there is a gap between what you know and what you need to know you have a(n ). 20. The factor adjusted by the experimenter is the. 21. A hard-to-understand idea may be represented or described by a(n). 22. A factor that does not change in an experiment is a(n). 23. A rule of nature is a scientific. 24. From the conclusion of an experiment, other events may be (inferred, repeated, refuted, and questioned). Answer the following questions. 25. What is the purpose of any experiment? 26. Does a conclusion always support a hypothesis? Why or why not? 27. What is the value of a control in an experiment? 28. How do science and technology differ? Observation vs. Inferences Directions: Label the following statements as either observation (O) or inference (I). 29. When I rang the doorbell, no one answered. 30. The hamburger was hot. 31. Jamal must be very popular. 32. The rabbit uses fur from her stomach to build her nest. 33. That sounded like a mean dog. 34. The rock feels like an ice cube. 35. Those clouds look like a mountain. 36. The beaker contains 250 ml of water. 37. The bark on the birch tree was white. 38. A gas was formed when I mixed the liquid and solid. 39. The faster car probably has a more powerful engine 3

4 Use the images below to answer questions On Monday afternoon, a student prepared a petri dish and then swabbed the school lunch table (left). On Tuesday, after cleaning the table with an antibacterial soap, she repeated the experiment (image on right). The following statements were made by the student conducting a lab. Please indicate whether each statement is an observation (O) or inference (I). Assume that the growth has been identified as bacteria. 40. There is more bacteria on the petri dish before the tables were cleaned. 41. The tables in the lunch room appear dirty. 42. Antibacterial soap smells like lemons. 43. Antibacterial soap kills bacteria. 44. If the tables are not properly cleaned, bacteria can grow on them. 45. The petri dishes were kept at 23 C. 46. The mass of each dish and the contents before the experiment was 35 grams. 47. Prior to this experiment, the tables have not been properly cleaned. 48. Fill in the blank spaces with either an observations or inferences: Observation Inference The temperature of the glass of water near the window is warmer than the water on the table. Adding grease to the gears caused the cart to roll faster. 4

5 Scientific Notation Write the following numbers in scientific notation: ,000, , ,000,000, , x x 10-6 Write the following in standard notation: x x x x x 10 7 Perform the following calculations (addition/subtraction) 63. (2.6 x 10 2 ) + (4.1 x 10 2 ) 64. (1.2 x 10 3 ) + (3.6 x 10 4 ) 65. (7.43 x 10 5 ) - (5.09 x 10 4 ) 66. (2.6 x 10-2 ) - (4.1 x 10-3 ) Perform the following calculations (multiplication/division) 67. (3.5 x 10 5 ) x (2 x 10 7 ) 68. (1.6 x 10-3 ) x (2.1 x 10-5 ) 69. (5.5 x 10 4 ) x (4.3 x 10 2 ) 70. (2.3 x 10-7 ) x (7.8 x 10 4 ) 71. (9.1 x 10 2 ) x (2.5 x 10 9 ) 72. (6.7 x 10 3 ) (6.7 x 10-6 ) 73. (8 x 10 8 ) (2 x 10 2 ) 74. (7.17 x 10-8 ) (1.72 x ) 5

6 75. (9.8 x )(2.5 x 10 3 ) (3.4 x )(6.0 x ) 76. (5 x )(1 x 10-9 ) (6 x )(4.5 x 10 4 ) Metric System- Vocabulary and Concepts 77. List the SI base unit of measurement for these quantities: a. time b. temperature c. length d. mass 78. What is the symbol and meaning of these common metric prefixes? a. milli b. deci c. centi d. kilo e. micro Match the prefixes with their equivalents. Write the letter of the correct value on the space provided. 79. nano A. 1/1000 (thousandth) B ( thousand) 80. centi C. 1/10 (tenth) D. 1/ ( millionth) 81. kilo E. 1/ ( billionth) F. 1/100 ( hundredth) 82. deci G. 10 (ten) 83. milli 84. micro List the basic SI units and abbreviation for each of the following quantities. Quantity SI Unit Abbreviation 85. length 86. mass 87. volume 88. area 89. density 90. time 6

7 Derived and Fundamental Units In the following equations, substitute the appropriate units for the symbols and find the units of the missing left-hand member. d, distance in meters v, velocity in m/sec a, acceleration in m/sec 2 t, time in sec m, (mass) in kg F, in newtons or kg-m/sec 2 91.? = vt 92.? = at 93.? = at 2 94.? = v/a 95.? 2 = ad 96.? = mv 2 /d 97.? = ma 98.? = mv/f 99.? = 4π 2 md/t ? = Ft 2 /4π 2 m 101.? = 2(d-vt)/t ? 2 = 4π 2 md/f Metric System Conversions I. Convert the following measurements to millimeters: m dm m x 10-6 cm II. Convert the following measurements to centimeters: mm m km dm III. Convert the following measurements to decimeters: m mm km m IV. Convert the following measurements to meters: cm mm mm km 7

8 V. Convert the following measurements to kilometers: m mm hm x 10 6 dm X. Convert the following measurements to decimeters: m x 10-4 cm XI. Convert the following measurements to meters: cm dm x 10-9 mm Mm XII. Convert the following to kilometers: cm Gm dm Significant Figures No measurement is absolutely certain. In other words, all measurements include a degree of uncertainty. The two main causes of uncertainty are (a) the skill and care of the person making the measurement and (b) the limitations of the measuring instrument. For both rulers below, the measurements indicated by the arrow is clearly between 2 cm and 3 cm. Estimate the measurement of each ruler and indicate the degree of uncertainty. 8

9 Determine the number of significant figures in each of the following measurements: kg ,000 m g m ,000,000 km , s cm g kg m L km cm s g g/ml ,000 mm x 10-5 mol K kg 151. Determine the number of significant digits and the uncertainty in each of the following. a g f g k cm 3 b kg g cm l m c ml h g m g d m i cm 3 n cm e g j cm o g 152. Express each answer using correct significant digits. Add. a cm + 8 cm cm b g g g c m m m m d g g g g Subtract. a km km c m m b g g d cm cm 9

10 Multiply a. 2.6 cm x 3.78 cm d km x 5.2 km b m x 0.02 m e dm x 2.5 dm x 4.00 dm c m x 0.02 m f cm x 0.78 cm x 2.3 cm Divide. a. 35 cm 2 / 0.62 cm d m 2 / m b. 39 g/ 24.2 g e km/1.62 km c dm 3 / 2.15 dm f g/ cm A piece of paper is 11.2 cm wide and 51 cm long. What is its area in square centimeters? In square meters? Accuracy and Precision 154. What is the difference between accuracy and precision? 155. Which student s data are precise? Explain. Student 1: g; g; g; g Student 2: g; g; g; g 156. Explain in your own words the range in heights that would be implied if you reported a measurement as His height is 182 cm Which of the following quantities could be determined exactly? a. Attendance at football game? b. Distance between goal posts at a football stadium? c. Number of grams in a sample of sugar? d. Number of inches in one yard? 158. Heather and Jason determined the density of a liquid three different times. The values they determined were 2.84 g/cm 3, 2.85 g/cm 3, and 2.80 g/cm 3. The accepted value is known to be 2.40 g/cm 3. a. Are the values that Heather and Jason determined precise? Explain. b. Are the values accurate? Explain. c. Calculate the percent error and the uncertainty for each measurement. 10

11 159. During a dental work or minor surgery, a local anesthetic, such as procaine or lidocaine, is used to deaden the pain in a small area of the body. Although both are about equally effective in numbing the pain, procaine is eight times more toxic than lidocaine. With which anesthetic is it more important to be precise and accurate in administering a dose? Explain When cutting the legs of a table to make it lower, precision is usually far more important than accuracy. Explain. 11