GRADE 8

STRAND 8.1: MATTER AND ENERGY INTERACT IN THE PHYSICAL WORLD 

The physical world is made of atoms and molecules. Even large objects can be viewed as a combination of small particles. Energy causes particles to move and interact physically or chemically. Those interactions create a variety of substances. As molecules undergo a chemical or physical change, the number of atoms in that system remains constant. Humans use energy to refine natural resources into synthetic materials.

Standard 8.1.1 - Develop a model to describe the scale and proportion of atoms and molecules. Emphasize developing atomic models of elements and their numbers of protons, neutrons, and electrons, as well as models of simple molecules. Topics like valence electrons, bond energy, ionic complexes, ions, and isotopes will be introduced at the high school level. (PS1.A)

Standard 8.1.2 - Obtain information about various properties of matter, evaluate how different materials’ properties allow them to be used for particular functions in society and communicate your findings. Emphasize general properties of matter. Examples could include color, density, flammability, hardness, malleability, odor, ability to rust, solubility, state, or the ability to react with water. (PS1.A)

Standard 8.1.3 - Plan and conduct an investigation and then analyze and interpret the data to identify patterns in changes in a substance's properties to determine if a chemical reaction has occurred. Examples could include changes in properties such as color, density, flammability, odor, solubility, or state. (PS1.A, PS1.B)

Standard 8.1.4 - Obtain and evaluate information to describe how synthetic materials come from natural resources, what their functions are, and how society uses these new materials. Examples of new materials could include medicine, foods, building materials, plastics, and alternative fuels. (PS1.A, PS1.B, ESS3.A)

Standard 8.1.5 - Develop a model that uses computational thinking to illustrate the cause and effect relationships in particle motion, temperature, density, and state of a pure substance when heat energy is added or removed. Emphasize molecular-level models of solids, liquids, and gases to show how adding or removing heat energy can result in phase changes and on calculating density of a substance’s state. (PS3.A)

Standard 8.1.6 - Develop a model to describe how the total number of atoms does not change in a chemical reaction, indicating that matter is conserved. Emphasize demonstrations of an understanding of the law of conservation of matter. Balancing equations and stoichiometry will be learned at the high school level. (PS1.B)

Standard 8.1.7 - Design, construct, and test a device that can affect the rate of a phase change. Compare and identify the best characteristics of competing devices, based on data analysis, and modify them to improve the device to better meet the criteria for success. (PS1.B, PS3.A, ETS1.A, ETS1.B, ETS1.C ).

STRAND 8.2: ENERGY IS STORED AND TRANSFERRED IN PHYSICAL SYSTEMS 

Objects can store and transfer energy within systems. Energy can be transferred between objects, which involves changes in the object’s energy. There is a direct relationship between an object’s energy, mass, and velocity. Energy can travel in waves and may be harnessed to transmit information.

Standard 8.2.1 - Use computational thinking to analyze data about the relationship between the mass and speed of objects to the relative amount of kinetic energy of the objects. Emphasis should be on the quantity of mass and relative speed to the observable effects of the kinetic energy. Examples could include a full cart vs. an empty cart or rolling spheres with different masses down a ramp to measure the effects on stationary masses. Calculations of kinetic and potential energy will be learned at the high school level. (PS3.A , PS3.C )

Standard 8.2.2 - Ask questions about how the amount of potential energy varies as distance within the system changes. Plan and conduct an investigation to answer a question about potential energy. Emphasize comparing relative amounts of energy. Examples could include a cart at varying positions on a hill or an object being dropped from different heights. Calculations of kinetic and potential energy will be learned at the high school level. (PS3.A , PS3.B )

Standard 8.2.3 - Engage in argument to identify the strongest evidence that supports the claim that the kinetic energy of an object changes as energy is transferred to or from the object. Examples could include observing temperature changes as a result of friction, applying force to an object, or releasing potential energy from an object. (PS4.A)

Standard 8.2.4 - Use computational thinking to describe a simple model for waves that shows the pattern of wave amplitude being related to wave energy. Emphasize describing waves with both quantitative and qualitative thinking. Examples could include using graphs, charts, computer simulations, or physical models to demonstrate amplitude and energy correlation. (PS4.A)

Standard 8.2.5 - Develop and use a model to describe the structure of waves and how they are reflected, absorbed, or transmitted through various materials. Emphasize both light and mechanical waves. Examples could include drawings, simulations, and written descriptions of light waves through a prism, mechanical waves through gas vs. liquids vs. solids, or sound waves through different mediums. (PS4.A, PS4.B)

Standard 8.2.6 - Obtain and evaluate information to communicate the claim that the structure of digital signals are a more reliable way to store or transmit information than analog signals. Emphasize the basic understanding that waves can be used for communication purposes. Examples could include using vinyl record vs. digital song files, film cameras vs. digital cameras, or alcohol thermometers vs. digital thermometers. (PS4.C)

STRAND 8.3: LIFE SYSTEMS STORE AND TRANSFER MATTER AND ENERGY 

Living things use energy from their environment to rearrange matter to sustain life. Photosynthetic organisms are able to transfer light energy to chemical energy. Consumers can break down complex food molecules to utilize the stored energy and use the particles to form new, life-sustaining molecules. Ecosystems are examples of how energy can flow while matter cycles through the living and nonliving components of systems.

Standard 8.3.1 - Plan and conduct an investigation and use the evidence to construct an explanation of how photosynthetic organisms use energy to transform matter. Emphasize molecular and energy transformations during photosynthesis. (PS3.D, LS1.C)

Standard 8.3.2 - Develop a model to describe how food is changed through chemical reactions to form new molecules that support growth and/or release energy as matter cycles through an organism. Emphasis is on describing that during cellular respiration molecules are broken apart and rearranged into new molecules, and that this process releases energy. (PS3.D, LS1.C)

Standard 8.3.3 - Ask questions to obtain, evaluate, and communicate information about how changes to an ecosystem affect the stability of cycling matter and the flow of energy among living and nonliving parts of an ecosystem. Emphasize describing the cycling of matter and flow of energy through the carbon cycle. (LS2.B, LS2.C)