Physical Science:Unit 3 – From Alchemy to Reality – How Can We Create New Substances: Introduction

Essential Question: How can we explain the surprising reaction between iron and sulfur?

Unit Storyline Synopsis: This unit focuses on chemical reactions, emphasizing both the changes in properties that can be detected before and after a reaction, and the law of conservation of mass. A surprising reaction between iron and sulfur is a jumping-off point. This unit also further explores the concept of energy in chemical reactions that will be highlighted in later studies of thermodynamics. By the end of this unit, chemistry is taken out of the lab and into the world, where scholars will learn more about the real-life applications of a substance’s chemical properties.

Why This Unit? After so many years of invention by scientists and engineers, how is it that new medications, fabrics, and other materials are still being created today? How is it possible that two substances, sitting calmly, can suddenly explode into a cascade of foam or burst into glowing flames when they come into contact? What are scientists really doing, at the molecular level, when they combine substances, and how do they classify the reactions they observe? Building upon their knowledge of elements, mixtures, compounds, and physical and chemical changes, scholars will solidify foundational understandings in chemistry and feel prepared to take on higher-level material in future units and physical science classes. By the end of this unit, chemistry is taken out of the lab and into the world, where scholars will learn more about the creation of new materials and the real-life applications of understanding a substance’s chemical properties.

Big Idea 1: Substances have unique physical and chemical properties.

• Substances react chemically in characteristic ways. In a chemical reaction, the atoms in the reactant(s) are rearranged into different molecules. The new product(s) created have different properties from those of the original substances.

Big Idea 2: Chemical reactions can be represented with chemical equations.

• In chemical equations, each atom is conserved, so mass is the same before and after the reaction.

How do Next Generation Science Standards practices and crosscutting concepts support mastery of the Big Ideas? Science and Engineering Practices highlighted in this unit:

• Analyzing and Interpreting Data
  • Analyze and interpret data to provide evidence for phenomena.
  • Consider limitations of data analysis (e.g., measurement error), and/or seek to improve precision and accuracy of data with better technological tools and methods (e.g., multiple trials).
• Constructing Explanations
  • Construct a scientific explanation based on valid and reliable evidence obtained from sources (including the students’ own experiments) and the assumption that theories and laws that describe the natural world operate today as they did in the past and will continue to do so in the future.
  • Apply scientific ideas, principles, and/or evidence to construct, revise, and/or use an explanation for real-world phenomena, examples, or events.

Crosscutting Concepts highlighted in this unit:

• Energy and Matter
  • Matter is conserved because atoms are conserved in physical and chemical processes.
  • Within a natural system, the transfer of energy drives the motion and/or cycling of matter.
• Systems and Systems Models
  • Models can be used to represent systems and their interactions such as inputs, processes, and outputs and energy and matter flows within systems.

Plan carefully for safety in all lessons. The top safety risks in this unit include:

• Lesson 2 uses detergent (dish soap). Review all safety information and the Safety Data Sheet for detergent to ensure proper safety precautions are taken before conducting this lesson. Ensure that scholars wear proper personal protective equipment (PPE) indicated for this lesson.
• Lessons 2, 4, 7, and 8 use baking soda. Review all safety information and the Safety Data Sheet for baking soda to ensure proper safety precautions are taken before conducting this lesson. Ensure that scholars wear proper PPE indicated for this lesson.
• Lessons 2, 7, and 8 use Review all safety information and the Safety Data Sheet for vinegar to ensure proper safety precautions are taken before conducting this lesson. Ensure that scholars wear proper PPE indicated for this lesson.
• Lessons 4 and 8 use calcium chloride. Review all safety information and the Safety Data Sheet for calcium chloride to ensure proper safety precautions are taken before conducting this lesson. Ensure that scholars wear proper PPE indicated for this lesson.
• Lesson 4 uses sodium carbonate. Review all safety information and the Safety Data Sheet for sodium carbonate to ensure proper safety precautions are taken before conducting this lesson. Ensure that scholars wear proper PPE indicated for this lesson.
• Lesson 4 uses magnesium sulfate (epsom salt). Review all safety information and the Safety Data Sheet for magnesium sulfate to ensure proper safety precautions are taken before conducting this lesson. Ensure that scholars wear proper PPE indicated for this lesson).
• Lesson 5 uses antacid tablets. Review all safety information and the Safety Data Sheet for ALKA-SELTZER to ensure proper safety precautions are taken before conducting this lesson. Ensure that scholars wear proper PPE indicated for this lesson).
• Lesson 7 uses iodine solution. Review all safety information and the Safety Data Sheet for iodine solution to ensure proper safety precautions are taken before conducting this lesson. Ensure that scholars wear proper PPE indicated for this lesson.
• Lesson 7 uses universal indicator solution. Review all safety information and the Safety Data Sheet for universal indicator solution to ensure proper safety precautions are taken before conducting this lesson. Ensure that scholars wear proper PPE indicated for this lesson.
• Lesson 7 uses baking powder. Review all safety information and the Safety Data Sheet for baking powder to ensure proper safety precautions are taken before conducting this lesson. Ensure that scholars wear proper PPE indicated for this lesson.
• Lesson 7 uses cornstarch. Review all safety information and the Safety Data Sheet for cornstarch to ensure proper safety precautions are taken before conducting this lesson. Ensure that scholars wear proper PPE indicated for this lesson.
• Lesson 7 uses potassium bitartrate (cream of tartar). Review all safety information and the Safety Data Sheet for potassium bitartrate to ensure proper safety precautions are taken before conducting this lesson. Ensure that scholars wear proper PPE indicated for this lesson.

Important Note: These lesson plans highlight some of the safety risks you should be aware of while teaching these lessons. These safety suggestions are not meant to take the place of a formal science safety training. Please be sure to follow all safety rules from your district, as well as all local, state, and federal science safety guidelines.

Engage: The unit begins with a fiery reaction: two molecules are heated, creating a spectacle. Scholars consider their prior knowledge of physical and chemical changes and begin a unit-long investigation to learn more about how and why substances react to one another.

• Lesson 1: Changes. Scholars begin the unit by observing a surprising reaction between two substances. To learn what caused it to occur, scholars will need to uncover lots of new information about chemical properties and changes. In this lesson, they begin by contrasting physical and chemical changes.

Explore: Before digging deeper, scholars need to understand the basics! Through experimentation and exploration, scholars learn more about how the atoms rearrange to form new products in a chemical reaction.

• Lesson 2: Reactants and Products. Scholars dive into the study of chemical reactions through an engaging challenge: to combine ingredients in such a way that the foam they produce reaches an exact, prescribed volume, without overflowing the container! In order to succeed, scholars must begin to conceptualize the relationship between the amounts of the reactants and products in a chemical reaction.
• Lesson 3: Chemical Equations Revealed. Building upon their understanding from the last lesson, scholars will uncover the basic mathematics of chemistry as they are exposed to their first balanced equations of the unit! Using a provided model, scholars will physically rearrange particles to form products from reactants.
• Lesson 4: Forming a Precipitate. Scholars may picture explosions, bubbling, and fizzing when they think of chemical reactions. In this lesson, they will be exposed to a new indicator of chemical changes the formation of a precipitate!

Explain: In a series of exciting labs, scholars uncover how to classify chemical reactions. Each day, they will unveil a new piece of information that helps them to better explain the fiery reaction they observed in Lesson 1.

• Lesson 5: The Law of Conservation of Mass. Scholars apply their conceptual understanding of chemical reactions from the previous lessons as they discover that mass is conserved in a chemical reaction.
• Lesson 6: Balancing Equations. Scholars will apply their understanding of the law of conservation of mass as they learn to balance chemical equations!
• Lesson 7: Mystery Powder. Scholars now know how to write a balanced chemical equation for known reactants and products. But what does one do if the identity of a substance is unknown? Scholars learn how to apply their understanding of chemical properties to identify a mystery substance given four options.
• Lesson 8: Energy Changes in Chemical Reactions. In the last unit, scholars were introduced to the terms endothermic and exothermic. Now, they will learn to apply these terms to chemical reactions, bringing them one step closer to a robust description to answer the unit’s Essential Question!
• Lesson 9: Types of Chemical Reactions. Scholars acquire additional information that will help them correctly classify the reaction they observed at the beginning of the unit. They learn that there are several types of chemical reactions, each with their own unique characteristics.

Elaborate: In this lesson, scholars “zoom out” from the Essential Question and focus on chemical reactions in the world around us. Scholars investigate how scientists apply their knowledge of chemical reactions to change our everyday lives.

• Lesson 10: Natural Resources and Synthetic Materials. Scholars learn that engineers and scientists have created a slew of new products and substances that play roles in our everyday lives using their knowledge of chemical reactions.

Evaluate: Scholars have studied hard and now have the opportunity to revisit the formerly unexplainable phenomenon at the center of the unit’s Essential Question. To prove their mastery of unit concepts, scholars are challenged to identify and describe that reaction and several others!

• Lesson 11: Identifying and Describing Chemical Reactions. The final challenge has arrived! Scholars finally have the opportunity to apply everything they have learned to explain the mysterious reaction from Lesson 1 and answer the unit’s Essential Question!

• Printable Exit Tickets
• Printable Lab Notebook