1. Multimedia presentation (PowerPoint or video) 2.

Transcription

1 UC Irvine FOCUS! 5 E Lesson Plan Title: Density is a Periodic Property Grade Level and Course: 8 th grade physical science, 10 th and 11 th grade chemistry Materials: Lead Shot, Pb g Silicon lumps, Si, 8-10 g Tin Shot, Sn, g Water Paper Towel Balance, Centigram (0.0l g precision) Beakers, 50-ml, or small cups, 3 Forceps or Tongs Graduated cylinder, 25-ml Instructional Resources Used: (concept maps, websites, think-pair-share, video clips, random selection of students etc.) 1. Multimedia presentation (PowerPoint or video) Think-pair-share - The think/pair/share strategy gives all students the opportunity to practice English by explaining science concepts. Provide students with time to write a response to a thought provoking question, then additional time to discuss it with their neighbor before sharing their conclusion with the class. The think/pair/share technique increases student participation and involvement, and is a particularly effective way of encouraging English language learners to express science concepts in English. Using the following questions for Think/Pair/Share activity: Why are the levels of these substances arranged in this particular order? What has kept the seven levels from mixing together to form a mixture? California State Standards: (written out) Grade 8: 5. Chemical reactions are processes in which atoms are rearranged into different combinations of molecules. As a basis for understanding this concept: a. Students know reactant atoms and molecules interact to form products with different chemical properties. 8. All objects experience a buoyant force when immersed in a fluid. As a basis for understanding this concept: a. Students know density is mass per unit volume.

2 b. Students know how to calculate the density of substances (regular and irregular solids and liquids) from measurements of mass and volume. Investigation and Experimentation: 9. Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other three strands, students should develop their own questions and perform investigations. Students will: a. Plan and conduct a scientific investigation to test a hypothesis. b. Evaluate the accuracy and reproducibility of data f. Apply simple mathematic relationships to determine a missing quantity in a mathematic expression, given the two remaining terms (including speed = distance/time, density = mass/volume, force = pressure x area, volume = area x height). Grades 9-12 Chemistry: Chemical Bonds 2a. Biological, chemical, and physical properties of matter result from the ability of atoms to form bonds from electrostatic forces between electrons and protons and between atoms and molecules. As a basis for understanding this concept: 2e. Students know how to draw Lewis dot structures Common Core State Standards: (written out) Lesson Objectives: 1. To determine the volume of an irregular object using water displacement. 2. To determine the density of an irregular object using mass and volume measurements. Differentiation Strategies to meet the needs of diverse learners: English Learners: 1. Students will locate the position of the elements silicon, tin, and lead on the periodic table. They will then draw, label and color the group 14 from the periodic table onto a separate sheet of paper. This will show them the position of the missing element germanium, the gap that Mendeleev s periodic table revealed in Within their lab groups, students can also benefit from the assistance of a peer tutor. Special Education: 1. The strategies outlined for English Learners are also appropriate for Special Education students as well. 2. Place students into mixed ability groupings to allow for peer tutoring and to promote deeper understanding of the content. GATE: 1. Students will research and study Mendeleev s version of the periodic table. Using information gained from this version, compare and contrast with the present day periodic table. Students will share their information with the class.

3 ENGAGE Describe how the teacher will capture the students interest. What kind of questions should the students ask themselves after the engagement? Using a seven level density column as a visual, as the students to discuss the following questions with a partner (Think Pair Share). After students have discussed in their small groups, they will participate in a whole class share out of ideas. 1. Why are the levels of these substances arranged in this particular order? 2. What has kept the seven levels from mixing together to form a mixture? EXPLORE Describe the hands-on laboratory activity that the students will be doing. List the big idea conceptual questions that the teacher will ask to focus the student exploration. Hands-on laboratory activity: Students will measure the mass and volume for silicon, tin and lead. Using this data, they will calculate the density for each element, and then use the results to predict the density of germanium, Mendeleev s undiscovered element in the Group IV family of elements. The volume of the element will be measured by water displacement. Big idea conceptual questions: What properties do Sn, Tin, and Si have in common? How can their properties be used to discover an unknown element? How can knowing the properties of various elements help us to determine the properties of others that are yet unknown and undiscovered? EXPLAIN What is the big idea concept that students should have internalized from doing the exploration? o Mendeleev arranged the known elements in a calendar-like table of rows and columns, in order of increasing atomic mass and repeating chemical properties. Based upon this arrangement, he discovered that there existed gaps of missing elements in the list of known elements. This knowledge may be applied to the present day to potentially identify the properties of additional, still unknown elements.

4 EVALUATE EXTEND List the higher order questions that the teacher will ask to solicit student explanations for their laboratory outcomes, and justify their explanations. 1. Explain how the periodic nature of the periodic table can tell us about yet another undiscovered element. 2. Knowing what you know about the physical properties of elements on the periodic table, would Mendeleev be pleased with the present day periodic table? Explain your answer. How will the student demonstrate their new understanding and/or skill? o Students will calculate the density of silicon, tin and lead, and accurately fill these values into their data tables. What learning product for the lesson? o Using a computer or graph paper, students will plot the period number of Si, Sn, and Pb. They will utilize correct procedure, plotting period number on the x-axis, and average density on the y-axis. Explain how students will develop a more sophisticated understanding of the concept. o How do the actual and predicted density values compare? Use the following equation to calculate the percent error between the predicted and actual values for the density lead, silicon, and tin. (Using this formula ) Percent = (actual Predicted) X 100% Actual How is this knowledge applied in our daily lives? o Density becomes important anytime someone wants to build something where weight and distribution of weight are critical. Ships require a ballast to stay upright in the water, while airplanes use counterweights to ensure they fly correctly. In either case, during the initial design, engineers must account for how much weight they need, and how much space must be allotted for it. To determine how much space they need, they must know the density of the materials they plan on using. Background Knowledge for the Teacher: At the time Mendeleev proposed the periodic law, the foundation of the modern periodic table or the classification of elements, 63 elements were known. Their physical and chemical properties had been studied and their atomic masses measured. Mendeleev arranged the known elements in a calendar-like table of rows and columns in order of increasing atomic mass and repeating chemical properties. It is at this point, however, that Mendeleev made a giant leap of discovery in which he suggested that there were some gaps or missing elements in the list of known elements. Sources: Flinn ChemTopic Labs The Periodic Table Volume 4, Science Framework for California Public Schools, for Kindergarten through Grade 12

5 Student pages are attached.

6 Density is a Periodic Property Lesson Objectives: To measure the mass and volume for silicon, tin and lead; To calculate the density for each element, and then use the results to predict the density of germanium, Mendeleev s undiscovered element in the Group IV family of elements. Materials: Lead Shot, Pb g Silicon lumps, Si, 8-10 g Tin Shot, Sn, g Water Paper Towel Balance, Centigram (0.0l g precision) Beakers, 50-ml, or small cups, 3 Forceps or Tongs Graduated cylinder, 25-ml Procedure: 1. Label three 50-ml beakers or small containers Si (silicon), Sn (tin) and Pb (lead). 2. Obtain approximately 8 g of silicon in the appropriately labeled beaker. Measure the combined mass of the beaker plus solid to the nearest 0.0lg and record the value in the Data Table. (Note: This value is the initial mass for sample 1.) 3. Fill a 25-mL graduated cylinder half-full with water. Measure the initial volume of water and record the value to the nearest 0.1mL in the Data Table. 4. Using forceps or tongs, carefully add about one-third of the silicon lumps to the graduated cylinder (enough to raise the water level in the cylinder by at least 1.0 ml). Add the solid slowly, so as to avoid splashing or breaking the glass cylinder. 5. Measure and record the new (final) volume of water plus in the graduated cylinder. 6. Measure and record the combined mass of the labeled beaker and remaining solid in the Data Table. (Note: This value is the final mass for sample 1.) 7. Repeat steps 4-6 twice with the remaining amount of solid in the beaker. Record all initial and final mass and volume data in the Data Table. There should be a total of three sets of mass and volume data (sample 1-3).

7 8. Empty the water from the graduated cylinder and carefully pour the silicon chunks onto a paper towel and allow them to dry. Do not allow any of the solid to go down the drain. 9. Rinse the graduated cylinder with water to make sure that all of the solid has been removed. 10. Obtain approximately 25 g of tin shot in the appropriately labeled beaker. Measure the initial mass of the container plus solid to the nearest 0.01 g and record the value in the Data Table. 11. Repeat steps 3-9 using tin. Record all initial and final mass and volume data in the Data Table. 12. Obtain approximately 35 g of lead shot in the appropriately labeled beaker. Measure the initial mass of the contained plus solid to the nearest 0.01 g and record the value in the Data Table. 13. Repeat steps 3-9 using lead. Record all initial and final mass and volume data in the Data Table. 14. Return the correctly labeled solids to your instructor for reuse. Data Table: Element Sample Initial Mass (g) Final Mass (g) Mass of Solid (g) Initial Volume (ml) Final Volume (ml) Volume Of Solid (ml) Silicon Tin Lead 1 2 3

8 Post-Lab Calculations and Analysis: (Use a separate sheet of paper to answer these questions) 1. Complete the Data Table: Calculate both the mass (initial mass final mass) and volume (final volume initial volume) of each sample 1-3 for all three elements, silicon, tin and lead. Record these result in the Data Table. 2. Using the mass and volume data, calculate the density of each sample 1-3 for all three elements. Construct a Results Table to summarize the results. Note: The density of a solid is usually reported in unit of g/cm 3. Recall that 1 ml = 1cm 3. Results Table Element Density (1) g/cm 3 Density (2) g/cm 3 Density (3) g/cm 3 Average Density g/cm 3 Silicon Tin Lead 3. Calculate the average value (mean) for the density calculation 1-3 for each element, silicon, tin and lead. Record all results in the Results Table. Use the range of density values for each element to estimate plus or minus (+ ) error for teach average (e.g., g/cm 3 ). 4. On a graph, plot the period number of Si, Sn, and Pb on the x-axis versus the average density of each element on the y-axis. Using a ruler or straightedge, draw a best-fit straight line through the data points. Use this best-fit straight line to predict the density of germanium. 5. Look up the actual density of germanium in a reference source and calculate the percent error between the predicted and actual values (see PreLab Question #3). 6. Explain how the periodic nature of the periodic table can tell us about yet another undiscovered element.