Surface Reflectivity

Plan an investigation to determine the relationships among the energy transferred, the type of matter, the mass, and the change in the average kinetic energy of the particles as measured by the temperature of the sample.

Develop and use a model to describe that waves are reflected, absorbed, or transmitted through various materials.

• Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.
• Each pure substance has characteristic physical and chemical properties (for any bulk quantity under given conditions) that can be used to identify it.
• Gases and liquids are made of molecules or inert atoms that are moving about relative to each other.
• In a liquid, the molecules are constantly in contact with others; in a gas, they are widely spaced except when they happen to collide. In a solid, atoms are closely spaced and may vibrate in position but do not change relative locations.
• Solids may be formed from molecules, or they may be extended structures with repeating subunits (e.g., crystals).
• The changes of state that occur with variations in temperature or pressure can be described and predicted using these models of matter.

• The term “heat” as used in everyday language refers both to thermal energy (the motion of atoms or molecules within a substance) and the transfer of that thermal energy from one object to another. In science, heat is used only for this second meaning; it refers to the energy transferred due to the temperature difference between two objects.
• The temperature of a system is proportional to the average internal kinetic energy and potential energy per atom or molecule (whichever is the appropriate building block for the system’s material). The details of that relationship depend on the type of atom or molecule and the interactions among the atoms in the material. Temperature is not a direct measure of a system's total thermal energy. The total thermal energy (sometimes called the total internal energy) of a system depends jointly on the temperature, the total number of atoms in the system, and the state of the material.
• Motion energy is properly called kinetic energy; it is proportional to the mass of the moving object and grows with the square of its speed.
• A system of objects may also contain stored (potential) energy, depending on their relative positions.
• Temperature is a measure of the average kinetic energy of particles of matter. The relationship between the temperature and the total energy of a system depends on the types, states, and amounts of matter present.

• When the motion energy of an object changes, there is inevitably some other change in energy at the same time.
• The amount of energy transfer needed to change the temperature of a matter sample by a given amount depends on the nature of the matter, the size of the sample, and the environment.
• Energy is spontaneously transferred out of hotter regions or objects and into colder ones.

• When light shines on an object, it is reflected, absorbed, or transmitted through the object, depending on the object’s material and the frequency (color) of the light.
• The path that light travels can be traced as straight lines, except at surfaces between different transparent materials (e.g., air and water, air and glass) where the light path bends.
• A wave model of light is useful for explaining brightness, color, and the frequency-dependent bending of light at a surface between media.
• However, because light can travel through space, it cannot be a matter wave, like sound or water waves.

• Develop and use a model to describe phenomena.
• Develop a model to describe unobservable mechanisms.
• Develop a model to generate data to test ideas about designed systems, including those representing inputs and outputs.
• Develop a model to predict and/or describe phenomena.

• Collect data to produce data to serve as the basis for evidence to answer scientific questions or test design solutions under a range of conditions.
• Plan an investigation individually and collaboratively, and in the design: identify independent and dependent variables and controls, what tools are needed to do the gathering, how measurements will be recorded, and how many data are needed to support a claim.
• Conduct an investigation and evaluate the experimental design to produce data to serve as the basis for evidence that can meet the goals of the investigation.

• Analyze and interpret data to determine similarities and differences in findings.
• Analyze and interpret data to provide evidence for phenomena.
• Analyze displays of data to identify linear and nonlinear relationships.
• Construct and interpret graphical displays of data to identify linear and nonlinear relationships.

• Cause and effect relationships may be used to predict phenomena in natural or designed systems.
• Relationships can be classified as causal or correlational, and correlation does not necessarily imply causation.
• Phenomena may have more than one cause, and some cause and effect relationships in systems can only be described using probability.

• Within a natural or designed system, the transfer of energy drives the motion and/or cycling of matter.
• Matter is conserved because atoms are conserved in physical and chemical processes.
• The transfer of energy can be tracked as energy flows through a designed or natural system.
• Energy may take different forms (e.g. energy in fields, thermal energy, energy of motion).

• Complex and microscopic structures and systems can be visualized, modeled, and used to describe how their function depends on the shapes, composition, and relationships among its parts, therefore complex natural structures/systems can be analyzed to determine how they function.
• Structures can be designed to serve particular functions by taking into account properties of different materials, and how materials can be shaped and used.

• Each atom has a charged substructure consisting of a nucleus, which is made of protons and neutrons, surrounded by electrons.
• The periodic table orders elements horizontally by the number of protons in the atom’s nucleus and places those with similar chemical properties in columns. The repeating patterns of this table reflect patterns of outer electron states.
• The structure and interactions of matter at the bulk scale are determined by electrical forces within and between atoms.
• A stable molecule has less energy than the same set of atoms separated; one must provide at least this energy in order to take the molecule apart.

• “Electrical energy” may mean energy stored in a battery or energy transmitted by electric currents.
• Energy is a quantitative property of a system that depends on the motion and interactions of matter and radiation within that system. That there is a single quantity called energy is due to the fact that a system’s total energy is conserved, even as, within the system, energy is continually transferred from one object to another and between its various possible forms.
• At the macroscopic scale, energy manifests itself in multiple ways, such as in motion, sound, light, and thermal energy.
• These relationships are better understood at the microscopic scale, at which all of the different manifestations of energy can be modeled as a combination of energy associated with the motion of particles and energy associated with the configuration (relative position of the particles). In some cases the relative position energy can be thought of as stored in fields (which mediate interactions between particles). This last concept includes radiation, a phenomenon in which energy stored in fields moves across space.

• Conservation of energy means that the total change of energy in any system is always equal to the total energy transferred into or out of the system.
• Energy cannot be created or destroyed, but it can be transported from one place to another and transferred between systems.
• Mathematical expressions, which quantify how the stored energy in a system depends on its configuration (e.g. relative positions of charged particles, compression of a spring) and how kinetic energy depends on mass and speed, allow the concept of conservation of energy to be used to predict and describe system behavior.
• The availability of energy limits what can occur in any system.
• Uncontrolled systems always evolve toward more stable states—that is, toward more uniform energy distribution (e.g., water flows downhill, objects hotter than their surrounding environment cool down).

• Atoms of each element emit and absorb characteristic frequencies of light. These characteristics allow identification of the presence of an element, even in microscopic quantities.
• Electromagnetic radiation (e.g., radio, microwaves, light) can be modeled as a wave of changing electric and magnetic fields or as particles called photons. The wave model is useful for explaining many features of electromagnetic radiation, and the particle model explains other features.
• When light or longer wavelength electromagnetic radiation is absorbed in matter, it is generally converted into thermal energy (heat). Shorter wavelength electromagnetic radiation (ultraviolet, X-rays, gamma rays) can ionize atoms and cause damage to living cells.
• Photoelectric materials emit electrons when they absorb light of a high-enough frequency.

• Use a model to provide mechanistic accounts of phenomena.
• Develop and use a model based on evidence to illustrate the relationships between systems or between components of a system.
• Use a model to predict the relationships between systems or between components of a system.

• Plan and conduct an investigation individually and collaboratively to produce data to serve as the basis for evidence, and in the design: decide on types, how much, and accuracy of data needed to produce reliable measurements and consider limitations on the precision of the data (e.g., number of trials, cost, risk, time), and refine the design accordingly.
• Science investigations use diverse methods and do not always use the same set of procedures to obtain data.
• New technologies advance scientific knowledge.
• Scientific inquiry is characterized by a common set of values that include: logical thinking, precision, open-mindedness, objectivity, skepticism, replicability of results, and honest and ethical reporting of findings.

• Analyze data using tools, technologies, and/or models (e.g., computational, mathematical) in order to make valid and reliable scientific claims or determine an optimal design solution.
• Apply concepts of statistics and probability (including determining function fits to data, slope, intercept, and correlation coefficient for linear fits) to scientific and engineering questions and problems, using digital tools when feasible.

• Empirical evidence is required to differentiate between cause and correlation and make claims about specific causes and effects.
• Systems can be designed to cause a desired effect.
• Cause and effect relationships can be suggested and predicted for complex natural and human designed systems by examining what is known about smaller scale mechanisms within the system.

• Energy cannot be created or destroyed–only moved between one place and another place, between objects and/or fields, or between systems.
• In nuclear processes, atoms are not conserved, but the total number of protons plus neutrons is conserved.
• The total amount of energy and matter in closed systems is conserved.
• Energy drives the cycling of matter within and between systems.
• Changes of energy and matter in a system can be described in terms of energy and matter flows into, out of, and within that system.
• Energy cannot be created or destroyed—it only moves between one place and another place, between objects and/or fields, or between systems.

• The functions and properties of natural and designed objects and systems can be inferred from their overall structure, the way their components are shaped and used, and the molecular substructures of its various materials.
• Investigating or designing new systems or structures requires a detailed examination of the properties of different materials, the structures of different components, and connections of components to reveal its function and/or solve a problem.