Topic: Conservation of Mass and Energy

Transcription

1 7 th Grade Science Unit: ABC: Acid Base Chemistry Unit Snapshot Topic: Conservation of Mass and Energy Grade Level: 7 Duration: 9 days Summary: The following activities engage students in exploring the acidity or alkalinity of substances (ph), through investigations involving ph testing and analysis. Students will then use their knowledge of ph values to analyze components of the natural world. CLEAR LEARNING TARGETS I can statements use the ph scale to compare and evaluate the acidity or alkalinity of a compound measure ph values in the natural world (e.g. soil, water). Activity Highlights and Suggested Timeframe Day 1 Day 2 Days 3-4 Days 5-7 Day 8 and ongoing Day 9 Engagement: The objective of this activity is to engage students and formatively assess their knowledge related to properties of acids and bases through a discrepant event acid/base demonstration called the Witch s Potion. Exploration: The objective of the following activity is to give students the opportunity to work with and begin to develop a basic understanding of the acidity or alkalinity of a substance through on-line simulation GIZMO: ph Analysis. Explanation: The objective of the following activity is to give students the opportunity to develop their knowledge of ph scale values through close reading and the CPO Lab Investigation 16B: Acids, Bases, and ph. Elaboration: The objective of the following activities is to give students the opportunity to gain deeper understanding of ph values through close reading and ph investigations involving substances in our natural world (e.g. water, soil). Evaluation: Formative and summative assessments are used to focus on and assess student knowledge and growth to gain evidence of student learning or progress throughout the unit, and to become aware of students misconceptions related to thermal energy transfer. A teacher-created short cycle assessment will be administered at the end of the unit to assess all clear learning targets (Day 8). Extension/Intervention: Based on the results of the short-cycle assessment, facilitate extension and/or intervention activities. 1

2 LESSON PLANS NEW LEARNING STANDARDS: 7.PS.1 The properties of matter are determined by the arrangement of atoms. Substances are classified according to their properties, such as metals and acids. SCIENTIFIC INQUIRY and APPLICATION PRACTICES: During the years of grades K-12, all students must use the following scientific inquiry and application practices with appropriate laboratory safety techniques to construct their knowledge and understanding in all science content areas: Asking questions (for science) and defining problems (for engineering) that guide scientific investigations Developing descriptions, models, explanations and predictions. Planning and carrying out investigations Constructing explanations (for science) and designing solutions (for engineering)that conclude scientific investigations Using appropriate mathematics, tools, and techniques to gather data/information, and analyze and interpret data Engaging in argument from evidence Obtaining, evaluating, and communicating scientific procedures and explanations *These practices are a combination of ODE Science Inquiry and Application and Frame-work for K-12 Science Education Scientific and Engineering Practices COMMON CORE STATE STANDARDS for LITERACY in SCIENCE: *For more information: CCSS.ELA-Literacy.RST Cite specific textual evidence to support analysis of science and technical texts. CCSS.ELA-Literacy.RST Determine the central ideas or conclusions of a text; provide an accurate summary of the text distinct from prior knowledge or opinions. CCSS.ELA-Literacy.RST Follow precisely a multistep procedure when carrying out experiments, taking measurements, or performing technical tasks. CCSS.ELA-Literacy.RST Determine the meaning of symbols, key terms, and other domain-specific words and phrases as they are used in a specific scientific or technical context relevant to grades 6 8 texts and topics. CCSS.ELA-Literacy.RST Compare and contrast the information gained from experiments, simulations, video, or multimedia sources with that gained from reading a text on the same topic. STUDENT KNOWLEDGE: Prior Concepts Related to Properties of Matter PreK-2: Properties can be used to sort objects. Changes, including phase changes are explored. Grades 3-5: Objects are composed of matter which has mass* and volume. Properties of solids, liquids and gases are explored. Phase changes are reversible and do not change the identity of the material. The total amount of matter and mass* remains the same when something changes. Grade 6: All matter is made up of atoms that are in constant random motion. Elements, compounds and molecules are introduced. The properties of solids, liquids and gases, and changes of phase are explained by the motion and spacing of the particles. Future Application of Concepts High School: Metalloids and ph calculations are introduced. Mixtures are classified as homogenous or heterogeneous. Trends in the properties and atomic structure of elements are related to the periodic table. The role of valence electrons in reactivity is explored, balanced chemical equations are written and stoichiometric problems are solved. 2

3 MATERIALS: Engage 5 500mL beakers or glasses Vinegar and Ammonia Phenolphthalein Indicator provided by CCS Science Department Water ph Analysis GIZMO Student Exploration Sheet Page 1 Blue and Red Litmus Paper Lemon Juice and Soap Explore Computers/Internet GIZMO lesson materials and Student Exploration Sheet Explain CPO Lab Investigation 16B Lab Materials Elaborate ph: A Balancing Act Student WS Soil and Water samples ph testing paper ph in Our Natural World: Water and Soil Student WS VOCABULARY: Primary Acidic Acidity Alkalinity Basic Neutral ph ph Scale Secondary Indicator Litmus Paper Phenolphthalein SAFETY ADVANCED PREPARATION ENGAGE (1 day) (What will draw students into the learning? How will you determine what your students already know about the topic? What can be done at this point to identify and address misconceptions? Where can connections are made to the real world?) During testing and investigation of chemicals/substances, students should wear safety glasses/goggles, and take other lab safety precautions. If possible, reserve computers lab/laptops for GIZMO: ph Analysis. Gather and prepare materials for witch s potion demo and CPO Investigation lab 16B. Objective: The objective of this activity is to engage students and formatively assess their knowledge related to properties of acids and bases through a discrepant event demonstration. What is the teacher doing? THE WITCH S POTION DEMO (Day 1) PREPARATION: See Teacher Information Sheet. The teacher should set-up the demonstration without students seeing what is being done. NOTE: Do not prepare too far in advance, as the liquids may evaporate causing the demonstration to not work properly. (5 minute maximum) It is suggested that you practice this demo before showing to students. The teacher chooses 4 volunteers to read the poem and assist in the demo. Ask students to hypothesize what may have occurred to cause the color changes. What are the students doing? THE WITCH S POTION DEMO (Day 1) 1. 4 students are involved in assisting during the teacher demonstration. 2. All students observe the demonstration and hypothesize what may have occurred to cause the color changes. 3

4 Project the GIZMO: ph Analysis on a screen or SMARTboard. If you are unfamiliar with GIZMO s or do not know your username/password, see your Math CCIT or call the CCS science x5297. Distribute Page 1 of the ph Analysis GIZMO Student Exploration Sheet. Additional lesson materials are available on the website. Facilitate as students answer and discuss prior knowledge questions. Small group activity or teacher demonstration - Use blue and red litmus paper to demonstrate the use of an indicator to determine if a substance is an acid or base by testing lemon juice and soap. -Lemon Juice is an acid and will turn blue litmus to red. -Soap is a base and will turn red litmus to blue. Facilitate the GIZMO Warm-up as a class, and also test water and vinegar. Relate the ph of ammonia, water and vinegar to the witch s potion demo. Optional: Use litmus paper to show that ammonia is a base, and vinegar is an acid and water is neutral. 3. Students complete prior knowledge questions on the WS. 4. Students test lemon juice and soap using litmus paper to determine if the substance is an acid or base. -This can also be a teacher demonstration. 5. As a class, students work together to learn how to use the GIZMO through the GIZMO Warm-up. -In addition to ammonia, also test water and vinegar. 6. Relate the results of the tests to the Witch s Potion Demo. 7. Optional: Use litmus paper to show that ammonia is a base, and vinegar is an acid and water is neutral. 8. Exit Ticket suggestion: Explain how the witch s potion worked, and how it relates to acids, bases, and indicators. 4

5 Objective: The objective of the following activity is to give students the opportunity to work with and begin to develop a basic understanding of the acidity or alkalinity of a substance through on-line simulation GIZMO: ph Analysis EXPLORE (1 day) (How will the concept be developed? How is this relevant to students lives? What can be done at this point to identify and address misconceptions?) What is the teacher doing? GIZMO: ph Analysis (Day 2) Activity A & B can be completed as a whole group class instruction with teacher facilitation or if possible, students working individually or partners on computers, laptops, or IPads. Additional lesson materials are available on the website. If you are unfamiliar with GIZMO s or do not know your username/password, see your Math CCIT or call the CCS science x5297. Follow-up with a class discussion What are the students doing? GIZMO: ph Analysis (Day 2) 1. Students work individually, with a partner, or as a class to test various substances to determine their ph value. -Complete Activity A & B Objective: The objective of the following activity is to give students the opportunity to develop their knowledge of ph scale values through the CPO Lab Investigation: Acids, Bases, and ph. EXPLAIN (2 days) (What products could the students develop and share? How will students share what they have learned? What can be done at this point to identify and address misconceptions?) What is the teacher doing? CPO LAB INVESTIGATION 16B (Days 3-4) Using the CPO textbook pp , have students compare the properties of acids and bases. Facilitate a close reading of CPO textbook p. 397 NOTE: The discussion of hydroxide and hydrogen ions as they relate to the ph scale is reserved for high school and will not be assessed at grade 7. Facilitate CPO Lab Investigation 16.B. What are the students doing? CPO LAB INVESTIGATION 16B (Days 3-4) 1. Using the CPO textbook pp , compare the properties of acids and bases. 2. Engage in a close reading of CPO textbook p Complete Lab Investigation 16B. 5

6 Objective: The objective of the following activities is to give students the opportunity to gain deeper understanding of ph values through ph investigations involving substances in our natural world. What is the teacher doing? ph in our Natural World(Day 5) What are the students doing? ph in our Natural World (Day 5) Facilitate a close reading of CPO textbook pp and/or Show the video clip: The ph in the Chemistry of Nature [3:19] 1. Students engage in close reading of CPO textbook pp and/or watch the video clip: The ph in the Chemistry of Nature [3:19] ELABORATE (3 days) (How will the new knowledge be reinforced, transferred to new and unique situations, or integrated with related concepts?) Distribute the WS ph: A Balancing Act. Split students into 4 groups and facilitate a close reading on pp in the CPO textbook. Facilitate the sharing of answers. Administer a quick write in student journals or on a separate piece of paper: Summarize how ph plays an important role in your body. What is the teacher doing? ph in our Natural World: WATER (Day 6) PREPARATION: Teacher collects water samples from various parts of the school (i.e. water fountain, bathroom sink, fish tanks, bottled water, etc.) or asks students to gather the water samples. It is recommended that students develop their own investigation for testing the ph of the water samples. However, a lab sheet template has been provided for those students that need a more guided experience: ph in Our Natural World: WATER WS. Teacher facilitates ph testing and investigation. OPTIONAL Extension: Test the effects of water ph on an Elodea plant (aquatic plant). 2. Using the CPO Textbook pp , students either read the sections aloud or silently. 3. Each group of students is assigned a set of questions to answer using their reading section and then present their findings to the class. 4. All students are responsible for summarizing the answer to each question on their WS. 5. Students perform a quick write summarizing how ph plays an important role in the body either in journals, or on the back of their paper. What are the students doing? ph in our Natural World: WATER (Day 6) 1. Students gather water samples from either home or different parts of the school yard/building 2. Students develop and investigate the ph of the water samples and complete lab sheet. 6

7 What is the teacher doing? ph in our Natural World: SOIL (Day7) PREPARATION: Teacher collects soil samples from various sources, asks students to bring in soil samples, or students gather soil samples from around the schoolyard. Include a fertilized potting soil sample, as fertilizer is a strong base. Teacher facilitates the gathering of soil samples and students ph testing. NOTE: Use distilled water to create soil solutions. It is recommended that students develop their own investigation for testing the ph of the soils. However, a lab sheet template has been provided for those students that need a more guided experience: ph in Our Natural World: SOIL WS NOTE: Students will be completing a similar lab using outside water sources during the Earth Science Unit. What are the students doing? ph in our Natural World: SOIL (Day 7) 1. Students gather soil samples from either home or different parts of the school yard. 2. Students develop an investigation to test and compare the ph of the soil samples and complete a lab report. EVALUATE (on-going) (What opportunities will students have to express their thinking? When will students reflect on what they have learned? How will you measure learning as it occurs? What evidence of student learning will you be looking for and/or collecting?) OPTIONAL Extension: Test the effects of soil ph on plant growth. Objective: The objective of the assessments is to focus on and assess student knowledge and growth to gain evidence of student learning or progress throughout the lesson, and to become aware of students misconceptions related to the alkalinity/acidity of substances and the ph Scale. Formative How will you measure learning as it occurs? Consider developing a teacher-created formative assessment. 1. Student s hypotheses based on the Witch s Potion Demo as well as priorknowledge/warm-up GIZMO questions can be used to formatively assess students prior knowledge of acids and bases. 2. GIZMO and Lab 16B questions/answers These can be used to assess the student s ongoing understanding of the ph scale. Summative What evidence of learning will demonstrate to you that a student has met the learning objectives? 1. ph in our Natural World Investigations can be used to assess the students ability to test and relate ph values to various aspects of the natural world. 2. Teacher-created short cycle assessment will assess all clear learning targets (Day 8). 7

8 EXTENSION/ INTERVENTION (1 day or as needed) COMMON MISCONCEPTIONS EXTENSION 1. Test acids/bases of various strengths to determine rates of corrosion on metal pennies. 2. CPO Chapter Activity: Acid Rain and Stone Structures on CPO textbook p GEO STAC: Acid Precipitation Lesson: acid-precipitation 4. ph and plant growth/survival investigation: depot/experiments/water/lessons/ph/ phlesson2.htm INTERVENTION 1. related videos 2. BBC KS3 Bitesize Interactive: Acids, bases, and metals - nce/chemical_material_behaviour/aci ds_bases_metals/activity/ 2. GEMS Alien Juice Bar - case/flash/juicebar.html 3. The ph Factor - All acids are corrosive. -Students can use litmus paper to test common foods to discover that many of the things they eat are acids. A base (alkalinity) is the opposite of an acid (acidity) and therefore not harmful or corrosive. -Bases have various strengths and can also be corrosive. The acidity/alkalinity strength is based on how much of the substance is present (e.g. the more substance there is, the stronger the acidity/alkalinity.) -ph is based on the chemical make-up of the substance, not the amount there is. Strategies to address misconceptions: Misconceptions can be addressed through the use of Discovery Ed video clips, and litmus/ph tests of various substances. Lower-level: Consider partnering lower-level students with higher-level students while working on GIZMO simulation or investigation activities; Consider assigning specific substances for testing during investigations; Consider performing a read-aloud during close reading assignments. Higher-Level: Consider providing opportunities for higher-level students to test other substances that they may choose; Consider allowing students to complete extension activities; Consider having students create assessment questions for review. DIFFERENTIATION Strategies for meeting the needs of all learners including gifted students, English Language Learners (ELL) and students with disabilities can be found at the following sites: ELL Learners: aspx?documentid= Gifted Learners: aspx?documentid= Students with Disabilities: ad.aspx?documentid=

9 Textbook Resources: CPO Physical Science Textbook Chapter 16.2: Acids, Bases, and ph pp CPO Lab Investigation 16B ADDITIONAL RESOURCES Websites: Phet Interactive Simulation: Acid-base basics: Acid-base chemistry: Acids, bases: es.html The ph scale: Natural indicators: Pickle science: Kitchen&id= Discovery Ed ( Elements of Chemistry: Acids, Bases, and Salts [20:00] Literature: Brent, Lynette. (2009).Acids and Bases. Crabtree Pub.Co. Baldwin, Carol. (2006). Acids & Bases. Raintree Publishers. Oxlade, Chris. (2007). Acids and Bases. Heinemann Library. 9

10 Teacher Info ENGAGE - THE WITCHES POTION DEMO PREPARATION: Prepare the following without letting students see what you are doing. However, do not prepare too far in advance, as the liquids may evaporate causing the experiment to not go as planned. Materials: 5 beakers (500 ml) or glasses Container of water Vinegar (Acid) Ammonia (Base) Phenolphthalein Indicator (turns pink in the presence of a base) Eye droppers Witch s Potion Poem Sheet 1. Prepare 4 beakers or glasses and label them: 2. In #1 and #3 put of phenolphthalein 3. In #2 and #4 put of ammonia (If you prepare these ahead of time, then be sure to stack them, one inside the other, with an empty one inside the top one. This prevents your drops from evaporating.) 4. In #5 put 20 drops of vinegar. 5. Fill a large container with water. phenolpthalein ammonia phenolpthalein ammonia 20 drops vinegar BEAKER #1 BEAKER #2 BEAKER #3 BEAKER #4 BEAKER #5 6. Choose 4 volunteers to be the 4 witches. These students will read their sections of the poem and do their section of the experiment. Teacher Background: What is actually happening? Phenolphthalein is a chemical indicator that turns pink in the presence of a base. Therefore when beaker #1 is added to beaker #2 and beaker #3 is added to beaker #4, the phenolphthalein reacts with the ammonia(base) and turns the solution bright pink. When the phenolphthalein/ammonia solutions are added to beaker #5, the ammonia (base) is neutralized by the vinegar (acid) and the solution turns clear again. 10

11 The Witches Potion Poem Teacher Information: Teacher/Narrator: Four witches made quite a commotion. When I invited them to create a potion. Into four glasses went the magic brew... Experiment Fill beakers #1-4 ¼ full with water. phenolpthalein ammonia phenolpthalein ammonia 20 drops vinegar BEAKER #1 BEAKER #2 BEAKER #3 BEAKER #4 BEAKER #5 Teacher/Narrator: "And into a rage the first witch flew: She shrieked, Witch #1: There's no magic in this drink. To cast a spell, it must be pink!" Teacher/Narrator: The second witch laughed, Witch #2: "The pink is here. Pour your brew in--the color will appear!" Experiment Witch #1 pour water into the glass of Witch #2. phenolpthalein ammonia phenolpthalein ammonia 20 drops vinegar BEAKER #1 BEAKER #2 BEAKER #3 BEAKER #4 BEAKER #5 11

12 Teacher/Narrator: "The third witch shrieked, Witch #3: We need more! Teacher/Narrator: And gave her brew to Witch number Four." Experiment Witch #3 pour water into the glass of Witch #4. phenolpthalein ammonia phenolpthalein ammonia 20 drops vinegar BEAKER #1 BEAKER #2 BEAKER #3 BEAKER #4 BEAKER #5 Witch #4"Now there are two glasses of pink, But no one asked me what I think! I'll invoke my powers to make it clear. Be Gone Pink! Watch it disappear!" Experiment Pour both glasses with the pink solution into Beaker #5. 10 drops phenolpthalein 10 drops ammonia 20 drops vinegar BEAKER #1 BEAKER #2 BEAKER #3 BEAKER #4 BEAKER #5 4 Student Witch s Sheet: 12

13 THE WITCHES POTION Teacher/Narrator: "Four witches made quite a commotion. When I invited them to create a potion. Into four glasses went the magic brew..." Experiment Fill each beaker ¼ full with water. Teacher/Narrator: "And into a rage the first witch flew: She shrieked, Witch #1: There's no magic in this drink. To cast a spell, it must be pink!" Teacher/Narrator: The second witch laughed, Witch #2: "The pink is here. Pour your brew in--the color will appear!" Experiment Witch #1 pour water into the glass of Witch #2. Teacher/Narrator: "The third witch shrieked, Witch #3: We need more! Teacher/Narrator: And gave her brew to Witch number Four." Experiment Witch #3 pour water into the glass of Witch #4. Witch #4:"Now there are two glasses of pink, But no one asked me what I think! I'll invoke my powers to make it clear. Be Gone Pink! Watch it disappear!" Experiment Pour both glasses with the pink solution into the large container. 13

14 Name: Date: Period Student Exploration: ph Analysis Vocabulary: acid, acidic, alkaline, base, indicator, neutral, ph Prior Knowledge Questions (Do these BEFORE using the Gizmo.) 1. Acids are substances that produce hydrogen ions (H + ) when dissolved in water. Lemon juice is an example of an acid. A. What does lemon juice taste like? B. What does it feel like if lemon juice gets in your eye? 2. Bases are substances that produce hydroxide ions (OH - ) when dissolved in water. Hand soap is an example of a base. A. What does soap feel like? B. What does soap taste like? C. What does it feel like if soap gets in your eye? Gizmo Warm-up The strength of an acid or base is measured on the ph scale. The term ph is short for potential of hydrogen. It is a measure of how many excess H + ions there are in a solution. The ph scale runs from 0 to 14, with 0 representing the highest concentration of hydrogen ions. Acidic substances have a ph below 7, while alkaline substances (bases) have a ph above 7. Pure water has a ph of 7 and is considered neutral. The ph Analysis Gizmo allows you to find the ph of a variety of liquids. In the Gizmo, check that the Substance in the tube is Ammonia, and click Test. Wait until the animation is finished. 1. Indicators change color in acids or bases. What is the color of the ph paper? 2. Compare the paper to the ph color chart. What is the ph of ammonia? 3. Is ammonia acidic or alkaline? 14

15 Name: Date: Period Activity A: Measuring ph Get the Gizmo ready: Click Reset. Check that the 0-14 paper is selected. Goal: Find the ph of 18 common substances. 1. Test: Use the Gizmo to find the ph of each of the available substances. Classify each substance as acidic (ph < 7), alkaline (ph > 7), or neutral (ph = 7) ph indicator paper Material in the tube ph value Acidic, alkaline, or neutral? Baking soda Bleach Coffee Cola Drain cleaner Hand soap Juice (lemon) Juice (orange) Juice (tomato) Milk Milk of magnesia Oven cleaner Saliva (human) Shampoo Stomach acid Vinegar Water (distilled) Water (ocean) 2. Summarize: Compare all the acidic substances and all the alkaline substances. A. In general, what types of substances tend to be acidic? B. What types of substances tend to be alkaline? Name: Date: Period 15

16 Activity B: More accurate ph Get the Gizmo ready: Click Reset. Select the paper. Goal: Find the ph of substances in a more accurate way. 1. Test: Before you begin testing with the paper, list the ph values of the substances below that you found using the 0-14 ph indicator paper. Then find the ph of each substance with the paper ph indicator paper Material in the tube ph value (0 to 14 paper) ph value (4.5 to 7.5 paper) Coffee Milk Oven cleaner Saliva (human) Shampoo Stomach acid Water (distilled) 2. Analyze: Compare the ph values in each column. A. How do these values compare? B. What is an advantage of using the paper? C. What is a disadvantage of using the paper? D. Given the results from two kinds of indicator paper, which substances appear to be neutral (ph = 7)? 16

17 ph Analysis Answer Key Vocabulary: acid, acidic, alkaline, base, indicator, neutral, ph Prior Knowledge Questions (Do these BEFORE using the Gizmo.) [Note: The purpose of these questions is to activate prior knowledge and get students thinking. Students are not expected to know the answers to the Prior Knowledge Questions.] 1. Acids are substances that produce hydrogen ions (H + ) when dissolved in water. Lemon juice is an example of an acid. A. What does lemon juice taste like? Lemon juice has a sour taste. B. What does it feel like if lemon juice gets in your eye? A burning sensation. 2. Bases are substances that produce hydroxide ions (OH - ) when dissolved in water. Hand soap is an example of a base. A. What does soap feel like? Soap has a slippery texture. B. What does soap taste like? Soap has a bitter taste. C. What does it feel like if soap gets in your eye? A burning sensation. Gizmo Warm-up The strength of an acid or base is measured on the ph scale. The term ph is short for potential of hydrogen. It is a measure of how many excess H + ions there are in a solution. The ph scale runs from 0 to 14, with 0 representing the highest concentration of hydrogen ions. Acidic substances have a ph below 7, while alkaline substances (bases) have a ph above 7. Pure water has a ph of 7 and is considered neutral. The ph Analysis Gizmo allows you to find the ph of a variety of liquids. In the Gizmo, check that the Substance in the tube is Ammonia, and click Test. Wait until the animation is finished. 1. Indicators change color in acids or bases. What is the color of the ph paper? Dark green 2. Compare the paper to the ph color chart. What is the ph of ammonia? Is ammonia acidic or alkaline? Alkaline 17

18 Activity A: Measuring ph Get the Gizmo ready: Click Reset. Check that the 0-14 paper is selected. Goal: Find the ph of 18 common substances. 1. Test: Use the Gizmo to find the ph of each of the available substances. Classify each substance as acidic (ph < 7), alkaline (ph > 7), or neutral (ph = 7) ph indicator paper Material in the tube ph value Acidic, alkaline, or neutral? Baking soda 8 Alkaline Bleach 11 Alkaline Coffee 5 Acidic Cola 2 or 3 Acidic Drain cleaner 13 Alkaline Hand soap 9 or 10 Alkaline Juice (lemon) 2 or 3 Acidic Juice (orange) 3 Acidic Juice (tomato) 4 Acidic Milk 6 or 7 Acidic or neutral Milk of magnesia 10 Alkaline Oven cleaner 13 or 14 Alkaline Saliva (human) 6 or 7 Acidic or neutral Shampoo 6 or 7 Acidic or neutral Stomach acid 1 Acidic Vinegar 4 Acidic Water (distilled) 6 or 7 Acidic or neutral Water (ocean) 8 Alkaline 2. Summarize: Compare all the acidic substances and all the alkaline substances. A. In general, what types of substances tend to be acidic? Fruit juices and other beverages or food (cola, coffee, vinegar) tend to be acidic. B. What types of substances tend to be alkaline? Most of the alkaline substances are cleaners. These include hand soap, oven cleaner, bleach, and drain cleaner. 18

19 Activity B: More accurate ph Get the Gizmo ready: Click Reset. Select the paper. Goal: Find the ph of substances in a more accurate way. 1. Test: Before you begin testing with the paper, list the ph values of the substances below that you found using the 0-14 ph indicator paper. Then find the ph of each substance with the paper ph indicator paper Material in the tube ph value (0 to 14 paper) ph value (4.5 to 7.5 paper) Coffee 5 5 Milk 6 or Oven cleaner 13 or * Saliva (human) 6 or Shampoo 6 or 7 7 Stomach acid 1 4.5* Water (distilled) 6 or 7 7 *Substances with a ph below 4.5 or above 7.5 cannot be measured accurately with the indicator paper. 2. Analyze: Compare the ph values in each column. A. How do these values compare? Most of the values are the same or nearly the same, but some are very different. B. What is an advantage of using the paper? It gives a more accurate ph value for substances with a ph between 4.5 and 7.5. C. What is a disadvantage of using the paper? The ph paper does not work for substances whose ph is not between 4.5 and 7.5. D. Given the results from two kinds of indicator paper, which substances appear to be neutral (ph = 7)? Shampoo and distilled water appear to be neutral. 19

20 Name Date Period ph: A Balancing Act CPO Textbook pp Directions: Using the CPO Textbook pp , read Acids, bases, and YOU as a class. Then, read your assigned section of ph: A Balancing Act. Answer your assigned questions and share your findings with the class. Group 1: Imbalances What is an acid-base balance? What two organs regulate this balance? How do they do this? Group 2: Acidosis and its causes What is acidosis? What are some causes of acidosis? Group 3: Alkalosis and its causes What is alkalosis? What are some causes of alkalosis? Group 4: Balancing Act: food, drink, exercise, calm, acid, base Is our body s ph perfectly neutral? In what ways can our diet affect the ph in our bodies? 20

21 Name Date Period ph: A Balancing Act CPO Textbook pp TEACHER-KEY Directions: Using the CPO Textbook pp , read Acids, bases, and YOU as a class. Then, read your assigned section of ph: A Balancing Act. Answer your assigned questions and share your findings with the class. Group 1: Imbalances What is an acid-base balance? What two organs regulate this balance? How do they do this? An acid-base balance is the ph balance that occurs within the human body. A balance is required for our organs and body to function properly. The two organs that regulate this balance are: 1) Lungs: dispose of excess CO2 2) Kidneys: remove excess acid in our blood and dispose of it as urine, Group 2: Acidosis and its causes What is acidosis? What are some causes of acidosis? Acidosis is a ph imbalance in which the body has too much acid. Causes: 1) Lung Disease 2) Smoking 3) Diabetes 4)Severe Diarrhea 5)Heart/Liver Failure 6)Kidney Disease 7) Prolonged Exercise Group 3: Alkalosis and its causes What is alkalosis? What are some causes of alkalosis? Alkatosis is a ph imbalance in which the body has too much base in the body s fluids. Causes: 1) Hyperventilation 2) Altitude 3)Any disease that causes the bod to lose too much CO2. Group 4: Balancing Act: food, drink, exercise, calm, acid, base Is our body s ph perfectly neutral? What is the normal ph of a healthy person? In what ways can our diet affect the ph in our bodies? No,the body s ph is slightly alkaline ( ) Too much meat and not enough veggies will cause ph to become too acidic. 21

22 Name Date Period Guiding questions: What is the ph of the water in the school? Does all water have the same ph? Hypotheses: ph in Our Natural World: WATER Procedures: 1) Gather water samples. Water Test Site: 2) Dip ph strips in your water solution and leave submerged for at least 2 seconds. Place your strips here. Observe color. Compare your strips to the ph key to approximate the ph of your water sample. Estimating to the nearest decimal, what is the ph? 3) Using graph paper, create a data table and record the results of all ph tests. Develop a graph using your data to show the comparison between various water samples and their ph levels. 22

23 Name Date Period Post-lab questions: 1) Compare and contrast the ph values of the various samples. Summarize the results. 2) Were your hypotheses correct? What is the average ph of the water in the school? Do all soils have the same ph? 3) What factors can affect the ph of water? Extension Guiding Question: How does the ph of water affect aquatic plant growth and survival? Develop an investigation that tests the growth of Elodea (an aquatic plant) in varying ph levels to determine which water ph level is best growth and survival. 23

24 Name Date Period ph in Our Natural World: WATER TEACHER KEY Guiding questions: What is the ph of the water in the school? Does all water have the same ph? Hypotheses: Answers Will Vary Procedures: 1) Gather water samples. Examples: Water Fountain, Bottled Water, Sink Water, Fish tank, etc. Water Test Site: 2) Dip ph strips in your water solution and leave submerged for at least 2 seconds. Place your strips here. Observe color. Compare your strips to the ph key to approximate the ph of your water sample. Estimating to the nearest decimal, what is the ph? Answers Will Vary 3) Using graph paper, create a data table and record the results of all ph tests. Develop a graph using your data to show the comparison between various water samples and their ph levels. Data will vary depending on samples 24

25 Name Date Period Post-lab questions: 1) Compare and contrast the ph values of the various samples. Summarize the results. Answers Will Vary 2) Were your hypotheses correct? What is the average ph of the water in the school? Answers Will Depend on Location No Does all water have the same ph? 3) What factors can affect the ph of water? Filtration systems (Treatment plant); pipes, organisms in water, pollution, run-off, soil composition through which water moves, etc.) Extension Guiding Question: How does the ph of water affect aquatic plant growth and survival? Develop an investigation that tests the growth of Elodea (an aquatic plant) in varying ph levels to determine which water ph level is best growth and survival. 25

26 Name Date Period ph in Our Natural World: SOIL Guiding questions: What is the ph of the soil around the school? Do all soils have the same ph? Hypotheses: Procedures: 1) Gather soil samples. Soil Test Site: 2) Create a soil solution by mixing your soil sample with distilled water. 3) Dip ph strips in your soil solution and leave submerged for at least 2 seconds. Place your strips here. Observe color. Compare your strips to the ph key to approximate the ph of your soil solution. Estimating to the nearest decimal, what is the ph? 4) Using graph paper, create a data table and record the results of all ph tests. Develop a graph using your data to show the comparison between various soils and their ph levels. 26

27 Name Date Period Post-lab questions: 1) Compare and contrast the ph values of the various samples. Summarize the results. 2) Were your hypotheses correct? What is the average ph of the soil around the school? Do all soils have the same ph? 3) What factors can affect the ph of soil? Extension Guiding Questions: Do you think all plants grow and survive in the same ph level soil? Develop an investigation that tests the growth of a particular plant in soils with varying ph levels to determine which soil is best for that particular plant. 27

28 Name Date Period ph in Our Natural World: SOIL Teacher Key Guiding questions: What is the ph of the soil around the school? Do all soils have the same ph? Hypotheses: Answers Will Vary Procedures: 1) Gather soil samples. Examples: Soil near trees, Garden, Fertilized potting soil, Flower beds, Soil Soil Test Site: under grassy area, Soil near road, etc. 2) Create a soil solution by mixing your soil sample with distilled water. 3) Dip ph strips in your soil solution and leave submerged for at least 2 seconds. Place your strips here. Observe color. Compare your strips to the ph key to approximate the ph of your soil solution. Estimating to the nearest decimal, what is the ph? Answers Will Vary 4) Using graph paper, create a data table and record the results of all ph tests. Develop a graph using your data to show the comparison between various soils and their ph levels. Data is dependent upon soil samples 28

29 Name Date Period Post-lab questions: 1) Compare and contrast the ph values of the various samples. Summarize the results. Answers Will Vary 2) Were your hypotheses correct? What is the average ph of the soil around the school? Answer Will Depend on Location No Do all soils have the same ph? 3) What factors can affect the ph of soil? Soil Composition, Acid Rain/Pollution in Area, Fertilizer, Animals in the Area, Vegetation, Soil forming factors, Rainfall and temperature, Extension Guiding Questions: Do you think all plants grow and survive in the same ph level soil? Develop an investigation that tests the growth of a particular plant in soils with varying ph levels to determine which soil is best for that particular plant. 29