***Note*** All numbers in the yellow squares refer to relevant Massachusetts Middle School Science Technology & Engineering Physical Science (MA STE MS-PS) frameworks, unless otherwise stated. For more detail, refer to the STE Frameworks document on the Resources page.

Unit Overview

During Unit 2, students will learn about how interactions on the microscale result in phenomena on the macroscale, whether they be chemical reactions, obtaining energy from food, or accelerated climate change. Over the course of the lessons, students will learn about the Small Particle Model, and use the rules to explain physical phenomena such as energy exchange through conduction, convection, and radiation, phase changes, chemical change, and the interactions between greenhouse gases and light. The overarching principle that unites all of the lessons is that of energy, whose exchange fuels all of the aforementioned changes. Students will carry out experiments, develop models, and engage in argumentation via the Claims, Evidence, Reasoning framework in order to understand essential chemistry on both the macro and micro scales. The unit project will involve using chemical engineering principles to design an incubator that could be used to keep reptile eggs safe while they were bing moved away from their nesting site.. According to NGSS: The performance expectations in PS1: Matter and its Interactions help students to formulate an answer to the question, “How do atomic and molecular interactions explain the properties of matter that we see and feel?” by building understanding of what occurs at the atomic and molecular scale. In middle school, the PS1 Disciplinary Core Idea from the NRC Framework is broken down into two sub-ideas: the structure and properties of matter, and chemical reactions. By the end of middle school, students will be able to apply understanding that pure substances have characteristic physical and chemical properties and are made from a single type of atom or molecule. They will be able to provide molecular level accounts to explain states of matters and changes between states, that chemical reactions involve regrouping of atoms to form new substances, and that atoms rearrange during chemical reactions. Students are also able to apply an understanding of the design and the process of optimization in engineering to chemical reaction systems. The performance expectations in PS3: Energy, help students formulate an answer to the question, “How can energy be transferred from one object or system to another?” At the middle school level, the PS3 Disciplinary Core Idea from the NRC Framework is broken down into four sub-core ideas: Definitions of Energy, Conservation of Energy and Energy Transfer, and Energy in Chemical Process and Everyday Life. Students develop their understanding of important qualitative ideas about energy including that the interactions of objects can be explained and predicted using the concept of transfer of energy from one object or system of objects to another, and the total change of energy in any system is always equal to the total energy transferred into or out of the system. Students understand that objects that are moving have kinetic energy and that objects may also contain stored (potential) energy, depending on their relative positions. Students will also come to know the difference between energy and temperature. The performance expectations in PS3 expect students to demonstrate proficiency in developing and using models, planning investigations, analyzing and interpreting data, and designing solutions, and engaging in argument from evidence; and to use these practices to demonstrate understanding of the core ideas in PS3.

Unit 2 Essential Questions

• How do atomic and molecular interactions account for the properties that we see and feel?
• How do we model the microscopic?
• What data do we use to determine that a chemical change has occurred?
• How can energy be transferred from one system or object to another?
• What microscopic properties determine how well heat is transferred between objects?
• How do we know that thermal energy is due to the motion of molecules?
• What are the consequences of combustion reactions for the world?
• How can technologies mitigate the impact of human-caused climate change?

Lesson Descriptions

Lesson 2.1-Classifying and modeling matter

In this lesson, students will classify substances based upon their properties, and then observe and integrate a microscale model that explains many of these properties.

Lesson 2.2-Evidence for the particulate nature of matter

Students will use the Small Particle Model to explain a series of experiments which are explained by particular properties of atoms and their arrangement.

Lesson 2.3-Energy exchange between liquids

Students will learn the definition of the calorie, perform heat exchange calculations, and then carry out mixing experiments to observe the flow of heat energy causing the thermal energy of samples to change.

Lesson 2.4-Energy exchange between different materials

Students will mix different substances and observe heat exchange in order to learn about specific heat capacity, and the distinctions between heat, temperature, and thermal energy.

Lesson 2.5-Energy exchange causing a phase change

Students will determine the number of calories required in order to cause a sample of solid water to melt, and will investigate the role of temperature in the rate of evaporation.

Lesson 2.6-Energy bar graphs

Students will apply what they have learned about heat flow, thermal energy, temperature change and phase change by completing energy bar graphs for several scenarios in which heat energy is exchanged.

Lesson 2.7-Evidence for chemical change

Students will carry out eight reactions at stations and collectively develop a list of things that we commonly see when a chemical reaction occurs.

Lesson 2.8-Modeling chemical change

Students will observe a combustion reaction and model the breaking of bonds in reactants and formation of bonds in the products with magnets and diagrams.

Lesson 2.9-Energy exchange in chemical reactions

Students will carry out an endothermic and an exothermic chemical reaction and model the behavior based upon bond breaking in reactants and bond formation in products.

Lesson 2.10-Chemical change energy bar charts

Students will model the energy exchanges that occur during endothermic and exothermic chemical reactions with energy bar charts.

Lesson 2.11-Carbon dioxide and the greenhouse effect

Students will use several online computer simulations in order to learn about the interactions between light and carbon dioxide gas that result in our planet's relatively stable average temperature.

Lesson 2.12-The greenhouse effect and climate change

Students will use an online computer model to examine the relationship between atmospheric carbon dioxide concentration and average global temperature, and to predict what will happen if our current CO2 output does not change.

Lesson 2.13-Microscopic properties of water

Students will use magnetic water molecules as a model for how water molecules interact, leading to interesting properties such as surface tension, cohesion, and flow rate.

Lesson 2.14-CO2 dissolving in water

Students will perform experiments to investigate and model which variables affect the solubility of carbon dioxide gas in water as a means to begin to understand the processes that lead to ocean acidification.

Lesson 2.15-Chemical changes with acids and bases

Students will carry out a series of reactions between common household materials and two chemical indicators (cabbage juice and pH paper) in order to observe similarities and differences between the substances, and to examine the relationship between increasing the concentration of the acid/base and the pH.

Lesson 2.16-Chemical reactions between CO2 and water

Students will observe the impact that dissolved carbon dioxide gas has on the pH of water, and will infer how this phenomenon is connected to ocean acidification.

Lesson 2.17-Ocean acidification

Students will read articles summarizing recent climate scientists' studies regarding the impacts of ocean acidification and view the "Acid Test" documentary.

Unit Project-Ridiculous Reptile egg Rescue!

Students will learn about the engineering design process by designing, prototyping, and re-designing small systems that use chemical reactions in order to make a solution with a stable temperature that could be used to incubate reptile eggs during a difficult move.