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Youngstown City Schools SCIENCE: CHEMISTRY UNIT #1: SAFETY / SCIENTIFIC METHOD / MEASUREMENTS (20 DAYS) 2013-2014 SYNOPSIS: This unit has a focus on safety that has students identifying and applying appropriate safety precautions in the laboratory and in scientific investigations. Students investigate how chemistry is studied using the scientific method. Students learn about the system of measurement units used by scientists and about expressing and dealing with the numbers that result from scientific measurements. Using safety principles and laboratory equipment techniques, students determine the density of an unknown substance. ENABLERS: Safety, laboratory equipment, scientific method, metric system, English-metric conversions, density, physical states of matter, physical and chemical properties, physical and chemical changes, pure substances, elements, compounds, mixtures STANDARDS I. SAFETY, SCIENTIFIC METHOD, AND MEASUREMENTS A. proper use and identification of laboratory equipment B. proper use of safety equipment (e.g., fire extinguisher, eye wash station, first aid kit) C. proper first aid procedures for accidents (e.g., acid spills, cuts, burns, chemicals in eyes) D. proper procedures for fires, waste disposal, broken glass, and unlabeled chemicals E. use and understanding of MSDS sheets F. identify questions and concepts that guide scientific investigations G. design and conduct scientific investigations 1. Proper way of writing lab reports: objectives, procedures, data tables, sample calculations, concluding questions 2. Safely use a variety of tools (e.g., hand tools, measuring instruments, calculators, and computers) H. use technology and mathematics to perform and improve investigations and communications I. formulate and revise explanations and models using logic and evidence (critical thinking) J. recognize and analyze explanations and models K. communicate and support a scientific argument L. use correct scientific protocols for quantifying the properties of matter accurately and precisely 1. Derive and interpret data from mathematical relationships using graphs, charts, and tables 2. Apply mathematical concepts in problem solving (e.g., geometry, trigonometry, and logarithms M. use metric measuring systems, significant figures, scientific notation, error analysis, and dimensional analysis 1. Demonstrate difference between precision and accuracy 2. Apply rules of significant digits and use correct units of measurement 3. Mathematically determine metric and temperature conversions 4. Experimentally determine the density of specific substances 5. Read and understand graphs, charts, and tables LITERACY STANDARDS RST 2: Determine the central ideas or conclusions of a text; summarize complex concepts, processes, or information presented in a text by paraphrasing them in simpler but still accurate terms. WHST 10: Write routinely over extended time frames (time for reflection and revision) and shorter time frames (a single sitting or a day or two) for a range of discipline-specific tasks, purposes, and audiences MOTIVATION 7/9/2013 TEACHER NOTES YCS Science: CHEMISTRY Unit 1 - - Safety – Scientific Method – Measurement 2013-2014 1 TEACHER NOTES MOTIVATION 1. Students watch the video “Safety in the Laboratory” Students keep a list of correct and safe procedures. Students formulate questions for class discussion. 2. Teacher shows students how their notes are to be taken and how they will be “evaluated;” explain that students will be asked not only to record key information but write reactions and reflections like a scientist would write, as per designate tasks, audiences, and purposes. 3. Students set personal and academic goals. Since this is the first unit, teacher models how to do this; offer samples from which students select and record for reference at the end of the unit 4. Preview for students what the Authentic Assessment will be and what they will be expected to do. 5. Students practice using the laboratory equipment (e.g. measuring the volume of water in a graduated cylinder, measuring the mass of objects using a triple beam balance, measuring temperature with a thermometer). TEACHING-LEARNING TEACHER NOTES 1. Teacher demonstrates the use of safety equipment in the classroom such as the fire extinguisher, eye wash station/shower, chemical spill kits, emergency gas shut off valve. Students take notes and record questions in notes. [IA, IB, ID, IE] 2. Teacher discusses scenarios and procedures for chemical and fire burns. Teacher discusses fire drill procedures and demonstration of Bunsen burner with safety pin removed. Students watch and write questions as they occur. Students take notes as instructed. Students record key information and reactions. [IC] 3. Students take the Safety Test and sign the Safety Contract. 4. Students perform activity Light a burner (attached on page 5). Teacher supervises the activity and watches safety procedures. Correct any safety issues immediately. Class discussion follows. [IA-D] 5. Students examine MSDS sheet and information (attached on page 6). Follow with class discussion [IE]. 6. Teacher explains concepts that guide scientific procedures and the scientific method. Students take notes and make comments or write questions in their notes as previously directed. [IF] 7. Students are given equal amounts of paper and masking tape. Students apply the ideals of the scientific method by designing and constructing a 6-foot free-standing tower out of the paper and masking tape while working in pairs. [IF – IK] 8. Teacher checks for pre-understanding of metric measurements by forming student groups. Each group is assigned different quantities (length/distance, weight, volume, time, 7/9/2013 YCS Science: CHEMISTRY Unit 1 - - Safety – Scientific Method – Measurement 2013-2014 2 TEACHING-LEARNING TEACHER NOTES temperature, electric current, potential difference, and heat). [IM] Students are asked to list what units would commonly be used to express the quantity they have been assigned. Expected answers are: a. Length/distance: inches, feet, yards, miles b. Weight: pounds, ounces, tons c. Volume: gallons, cups, teaspoons, tablespoons, fluid ounces d. Time: days, years, hours, minutes, seconds e. Temperature: degrees Fahrenheit f. Electric current: amperes g. Potential difference: volts h. Heat: British thermal units 9. Using pages 12-15 of the Holt Chemistry textbook, students identify the SI units of measurement. Teacher explains conversion factors using the Skills Toolkit on page 13. Students use the conversion factors to convert metric prefixes to English conversions. Teacher discusses answers and procedures to correctly convert measurements. Use remediation as necessary. [IM2 – IM3] 10. Students demonstrate temperature conversions (Fahrenheit, Celsius, and Kelvin) by solving problems on the handout “Temperature Conversions.” Visit this website for example http://www.teachengineering.org/collection/cub_/activities/cub_energy2/cub_energy2_ lesson06_activity1_tempconversionworksheet.pdf [IM3] 11. Students perform the Lab “Measurement and Significant Figures” (attached on pages 79) to demonstrate reading metric measurements on a meter stick, balance, and graduated cylinder. Students keep careful records of data and gather in small groups to compare and analyze data with other groups. Follow with class discussion. [IJ-K] [IM2 – IM3] 12. Students use outside sources (text, internet, etc.) to graphically illustrate the difference between precision and accuracy. These are to be presented to the class. Teacher leads discussion to clear up any misinformation. [IM1] 13. Teacher performs several demonstrations of density (e.g. density column, using density blocks, etc.). Teacher explains concept of density (i.e., relationship between mass and volume); students take notes (NOTE: do not tell students the density of water) [IM4] a. demonstrate formula D = M / V b. explain that mass is measured in kg (remind students about converting one metric unit of mass or volume to another - - e.g., grams to kilograms and milliliters to liters, etc.) c. explain that volume is measured in mL and cm3 d. explain that density is a derived unit ( gram/cm3 or g/mL); explain density as “derived” measure and show what this means. Students take notes following the format shown earlier 14. Students perform the Labs “Density” and “Construction of a Graph,” (attached on pages 10-11) students learn to calculate slope; that density of water is 1g/mL; measure mass and volume to calculate density; and to create a graph; students complete a lab report. Lab reports will be returned and discussed as a class. [IH1] [IM4-5] 15. Teacher uses Prediction Guide to assess readiness by asking students to decide whether the following statements are true or false: [IL – IM] a. The terms accuracy and precision mean the same thing. 7/9/2013 YCS Science: CHEMISTRY Unit 1 - - Safety – Scientific Method – Measurement 2013-2014 3 TEACHING-LEARNING TEACHER NOTES b. It is important to write out all the digits of a number when answering chemistry problems. c. The number of digits written in an answer problem is important. d. Scientific notation can be used for convenience. e. Some values have an infinite number of significant figures. 16. Teacher explains the concept of significant figures and calculations using significant figures. Students demonstrate expressing significant figures in calculations using their scientific calculators. Students perform the Lab “Conversion Factors in Calculations.” ( Attached on page 12-13) [IM2 – IM3] 17. Teacher models how to analyze scientific text to find central idea and trace the author’s development of that idea through the text. Use A Basic Guide To Text Analysis (attached on page 14). Article comes from the following website: http://science.nasa.gov/sciencenews/science-at-nasa/2007/08jan_metricmoon/ [RST.2] 18. Students read a scientific text http://www.nist.gov/pml/wmd/metric/upload/meas-in-sport.pdf on their own or in groups to determine the central ideas or conclusions of a text; trace the text’s explanation or depiction of a complex process, phenomenon, or concept; provide an accurate summary of the text (e.g., metrics in sports). [RST.2] TRADITIONAL ASSESSMENT TEACHER NOTES 1. Unit Test: Multiple-Choice and 2-and 4-point response essays TEACHER CLASSROOM ASSESSMENT TEACHER NOTES 1. Safety Quiz 2. Lab Equipment Quiz (Students must score 80% or higher in order to pass.) 3. Lab reports or practical reports, using rubrics for quality points. 4. Assignments / worksheets AUTHENTIC ASSESSMENT TEACHER NOTES 1. Students evaluate their goals for the Unit. 2. Students devise a safety plan for the classroom in the case of an emergency chemical spill or fire. 3. Students write the procedure to determine the density of an unknown substance (e.g. an irregular solid or an unknown liquid); students use safe and proper laboratory techniques to successfully identify the name of the unknown liquid 7/9/2013 YCS Science: CHEMISTRY Unit 1 - - Safety – Scientific Method – Measurement 2013-2014 4 7/9/2013 YCS Science: CHEMISTRY Unit 1 - - Safety – Scientific Method – Measurement 2013-2014 5 Have students look at chemical containers MSDS sheets as this information is discussed. 7/9/2013 YCS Science: CHEMISTRY Unit 1 - - Safety – Scientific Method – Measurement 2013-2014 6 Measurements and Significant Figures Lab Purpose: The aim of this lab is to practice recording measurements with the correct number of significant figures. Procedure: 1. Several stations have been set up around the room. Step up to a station, read the directions, and read the measurement according to the directions. Record this measurement with the correct units in the slot in your data table that corresponds to the station number. Although you and your team mates may mass the objects together at stations 4, 6, and 7, you must read the instruments yourself and should not copy a peer's measurement. Station # 1 Measuring tool Measurement (with unit) 2 3 4 5 6 7 8 9 10a 10b 10c 11 7/9/2013 YCS Science: CHEMISTRY Unit 1 - - Safety – Scientific Method – Measurement 2013-2014 7 Discussion and Analysis: 1. Which stations required no approximation of the last significant figure? Why? 2. Did the estimations of you and your group mates always match? Why or why not? 3. Why is it important in lab activities to have one lab partner measure both the beginning and final measurements for a specific tool? Station 1: Meter stick Directions: Measure the piece of paper in centimeters, being sure to estimate visually the last readable number. Measure value to the nearest 0.01 cm. Station 2: Graduated cylinder: Directions: Measure the liquid in the graduated cylinder to the nearest 0.1 mL, being sure to estimate visually the place after the decimal. Record measurement to the nearest 0.1 mL. Station 3: Buret: Directions: Burets are measured from the top down. Be sure to honor this as you read the volume of the liquid inside to the nearest 0.01 mL. Record this measurement in your table. Station 4: Triple Beam Balance: Directions: Adjust the balance to zero if necessary then place the object on the balance and adjust the balance to accurately read the mass of the piece of metal. Record this measurement to the nearest 0.01 g in your table. When you finish, remove the object and place the balance back to zero. Station 5: Graduated cylinder: Directions: Measure the liquid in the graduated cylinder to the nearest 1 mL, being sure to estimate visually the place after the decimal. Discuss with your partner what each graduated line means before measuring. Record measurement to the nearest 1 mL. Station 6. Electronic balance: Directions: Tare the balance to zero, check that the units are in grams and place the object on the balance. When the measurement on the scale stabilizes, record the mass to the nearest 0.1 g in your data table. Station 7: Analytical balance: Directions: With glass doors closed, zero the balance. Open a glass door, place the metal on the balance, close the door, and record the measurement once it equilibrates in your data table to the nearest 0.001 g. Remove the metal when you finish and close the glass door. Station 8: Ruler 7/9/2013 YCS Science: CHEMISTRY Unit 1 - - Safety – Scientific Method – Measurement 2013-2014 8 Directions: Measure the length of the metal cylinder to the nearest 0.01 cm. Record this measurement under station 8 in your data table. Station 9: Ruler Directions: Measure the diameter of the metal cylinder to the nearest 0.01 cm. Record this measurement in your data table. Station 10: Best for liquids a. Record in your data table which of the three items would be best for measuring 9 mL of liquid. b. Record in your data table which of the three items would be best for measuring 26 mL of liquid. c. Record in your data table which of the three items would be best for measuring 155 mL of liquid. Station 11: Thermometer Directions: Read the temperature of the liquid to the nearest 0.1 degree and record this value in your data table. Remember that the thermometer must remain in the liquid during the reading for an accurate temperature. 7/9/2013 YCS Science: CHEMISTRY Unit 1 - - Safety – Scientific Method – Measurement 2013-2014 9 Density Lab The density of a pure substance does not depend upon the amount of that substance. Like temperature or melting point, density is an intensive property. That is, a ton of lead has the same density as a milligram of lead (11.63g/cm3). Common units for density are grams per cubic centimeter for solids, grams per milliliter for liquids, and grams per liter for gases. In this lab we will work with solids. Purpose: To develop the formula for density from experimental data by graphical interpretation, and to make comparisons in the densities of two different metals. Materials: Various sized graduated cylinder (10-100 ml) 6-8 metallic objects centigram balances Procedure: 1) Pick up a container holding 8-10 metallic objects. These objects are not marked. It will be the duty of one person to be sure to keep track of which objects have massed and keep the process orderly. 2) First determine the masses of each object by laying it on the balance pan and determining its mass. Be sure that the metallic object is dry. 3) After each object's mass has been determined, carefully lower the metallic object in to a graduated cylinder (choose a cylinder slightly larger than the piece, a 25 mL may work for all pieces) containing an accurately measured amount of water. I suggest you have 5.0 ml of water already in the graduated cylinder. Be sure that the metallic object is completely submerged in the water before taking a new reading off the graduated cylinder. This method of determining the volume of an irregularly shaped object is called volume displacement. At the end of the writing is an example data table for you to use in recording your experimental data. Make a graph of mass versus volume. Record the mass along the vertical axis and the volume in ml along the horizontal axis. Plot all data points on the graph. Give the graph a title; follow accepted graphing procedures. 7/9/2013 YCS Science: CHEMISTRY Unit 1 - - Safety – Scientific Method – Measurement 2013-2014 10 Findings: 1. Is the origin (0,0) a valid point? Explain. 2. Draw a line or lines that best "fits" the data. The line or lines should be a straight line. 3. How many lines were plotted on the graph? What importance can be attached to this observation to help make sense of the experiment? 4. The formula for a straight line is y=mx+b. What is the value (number reading) of b on your graph? Since b = ____, the y = ____. 5. Substitute into the amended equation mass for y, and volume for x. Then solve for m, the slope of the line. 6. Identify a physical property equal to the solution for m in question 4? 7. On your graph draw a perpendicular line form the 4-ml mark on the x-axis until it intersects the plotted lines. From the point of intersections, draw a line that is perpendicular to the y-axis. Using axis readings, determine the density represented by each slope? 8. Use the data table to determine the densities of each metal sample. How do these values compare with the density values determined by reading the graph. 9. A liquid occupies 12.6 ml has a mass of 11.2 grams. Find the density of the liquid. 10. Write a summary that explains what you learned from doing this experiment. 7/9/2013 YCS Science: CHEMISTRY Unit 1 - - Safety – Scientific Method – Measurement 2013-2014 11 Name: Date: Measurement Conversions [Metric to English] 1. 74 cm = __________ in. 2. 25 ml = __________ tsp. 3. 50 kg = __________ lbs. 4. 160 km = __________ mi. 5. 3.6 l = __________ gal. 6. 500 g = __________ oz. 7. 100 m = __________ yds. 8. 300 ml = __________ cups. 9. 600 g = __________ lbs. 10. 7/9/2013 523 mm = __________ in. YCS Science: CHEMISTRY Unit 1 - - Safety – Scientific Method – Measurement 2013-2014 12 Name: Date: Measurement Conversions [Metric to Metric] 1. 3.68 kg = __________ g 2. 568 cm = __________ m 3. 8700 ml = __________ l 4. 25 mg = __________ g 5. 0.101 cm = __________ mm 6. 250 ml = __________ l 7. 600 g = __________ kg 8. 8900 mm = __________ m 9. 0.000004 m = __________ mm 10. 7/9/2013 0.250 kg = __________ mg YCS Science: CHEMISTRY Unit 1 - - Safety – Scientific Method – Measurement 2013-2014 13 7/9/2013 YCS Science: CHEMISTRY Unit 1 - - Safety – Scientific Method – Measurement 2013-2014 14