8.2: Elements have distinct macroscopic properties and atomic structures. As a basis for understanding this concept, students:

8.2.1: Explain that all matter is made up of atoms that are far too small to see directly through an optical microscope.

Element Builder

8.2.2: Construct a model of an atom and know the atom is composed of protons, neutrons, and electrons.

Bohr Model of Hydrogen
Bohr Model: Introduction
Electron Configuration
Element Builder
Nuclear Decay

8.2.4: Diagram and describe how atoms may combine (bond) into molecules or into large crystalline arrays.

Covalent Bonds
Limiting Reactants

8.2.6: Describe how elements can be classified, based on similar properties, into categories, including highly reactive metals, less reactive metals, highly reactive non-metals, less reactive non-metals, and some almost completely non-reactive (noble) gases.

Electron Configuration
Element Builder
Ionic Bonds

8.2.7: Understand how an ion is an atom or group of atoms (molecule) that has acquired an electric charge by losing or gaining one or more electrons.

Dehydration Synthesis
Ionic Bonds

8.2.8: Describe how the atoms, molecules, or ions comprising an object are in constant individual motion, and explain how their average motional (kinetic) energy determines the temperature of the object and how the strength of the forces between them determines the state of matter at that temperature.

Collision Theory
Dehydration Synthesis
Phase Changes
Temperature and Particle Motion

8.2.9: Explain that the melting and/or boiling temperature of a substance (element or compound) depend on pressure and are independent of the amount of the sample. (Some materials don't melt and others don't boil because they decompose as the temperature is raised; other materials don't have a sharp melting point because they are not homogeneous.)

Colligative Properties
Freezing Point of Salt Water
Phase Changes

8.2.10: Describe the contributions of the scientists involved with the development of current atomic theory, including John Dalton, Marie and Pierre Curie, Joseph John Thomson, Albert Einstein, Max Planck, Ernest Rutherford, Niels Bohr, and Erwin Schroedinger.

Bohr Model of Hydrogen
Bohr Model: Introduction

8.3: Chemical reactions are processes in which atoms are rearranged into different combinations of molecules. As a basis for understanding this concept, students:

8.3.1: Discover and explain how elements and compounds (reactants) react with each other to form products with different properties.

Limiting Reactants

8.3.2: Describe Antoine Lavoisier's work, including the idea that when materials react with each other, many changes can take place, but that in every case the total amount of matter afterward is the same as before (Law of Conservation of Matter).

Balancing Chemical Equations
Chemical Equation Balancing
Limiting Reactants
Stoichiometry

8.3.3: Explain how the idea of atoms, as proposed by John Dalton, explains the conservation of matter: In chemical reactions, the number of atoms stays the same no matter how they are arranged, and the mass of atoms does not change significantly in chemical reactions, so their total mass stays the same.

Balancing Chemical Equations
Chemical Equation Balancing
Covalent Bonds
Electron Configuration
Limiting Reactants
Nuclear Decay
Stoichiometry

8.3.5: Investigate and explain that reactions occur at different rates, slow to fast, and that reaction rates can be changed by changing the concentration of reactants, the temperature, the surface areas of solids and by using a catalyst.

Collision Theory

8.3.7: Recognize that indicators of chemical changes include temperature change, the production of a gas, the production of a precipitate, or a color change.

Temperature and Particle Motion

8.4: All objects experience a buoyant force when immersed in a fluid. As a basis for understanding this concept, students:

8.4.1: Demonstrate that the mass of an object is a measure of the quantity of matter it contains (measured in kg or g), and its weight (measured in N) is the magnitude of the gravitational force exerted by the Earth on that much mass.

Beam to Moon (Ratios and Proportions)

8.4.2: Know density is mass per unit volume.

Density Experiment: Slice and Dice
Density Laboratory
Density via Comparison
Determining Density via Water Displacement

8.4.3: Investigate and explain that equal volumes of different substances usually have different masses and, therefore, different densities.

Density Experiment: Slice and Dice
Density Laboratory
Density via Comparison
Determining Density via Water Displacement

8.4.4: Determine and explain that the buoyant force on an object in a fluid is an upward force equal to the weight of the fluid the object has displaced; this principle can be used to predict whether an object will float or sink in a given fluid.

Density Laboratory
Density via Comparison

8.4.5: Determine the density of substances (regular and irregular solids, and liquids) from direct measurements of mass and volume, or of volume by water displacement.

Density Experiment: Slice and Dice
Density Laboratory
Density via Comparison
Determining Density via Water Displacement

8.5: Energy and matter have multiple forms and can be changed from one form to another. As a basis for understanding this concept, students:

8.5.1: Explain how energy is the ability to do work and is measured in joules (J)..

Inclined Plane - Simple Machine
Pulley Lab

8.5.2: Describe kinetic energy as the energy of motion (e.g., a rolling ball), and potential energy as the energy of position or configuration (e.g., a raised object or a compressed spring).

Air Track
Energy of a Pendulum
Inclined Plane - Rolling Objects
Inclined Plane - Simple Machine
Inclined Plane - Sliding Objects
Period of a Pendulum
Potential Energy on Shelves
Roller Coaster Physics
Simple Harmonic Motion

8.5.3: Investigate and explain how kinetic energy can be transformed into potential energy, and vice versa (e.g., in a bouncing ball).

Energy Conversion in a System
Energy of a Pendulum
Inclined Plane - Rolling Objects
Inclined Plane - Simple Machine
Inclined Plane - Sliding Objects
Period of a Pendulum
Roller Coaster Physics
Simple Harmonic Motion

8.5.4: Recognize and describe that energy is a property of many systems and can take the forms of mechanical motion, gravitational energy, the energy of electrostatic and magnetostatic fields, sound, heat, light (electromagnetic field energy)..

Calorimetry Lab
Energy Conversion in a System
Energy of a Pendulum
Inclined Plane - Simple Machine
Inclined Plane - Sliding Objects
Roller Coaster Physics

8.5.5: Describe that energy may be stored as potential energy in many ways, including chemical bonds and in the nucleus of atoms.

Covalent Bonds
Element Builder

8.5.6: Explain that the sun emits energy in the form of light and other radiation, and only a tiny fraction of that energy is intercepted by the Earth.

Herschel Experiment

8.5.7: Know the sun's radiation consists of a wide range of wavelengths, mainly visible light and infrared and ultraviolet radiation.

Herschel Experiment

8.5.8: Investigate and explain that heat energy is a common product of an energy transformation, for example, in biological growth, the operation of machines, the operation of a light bulb, and the motion of people.

Calorimetry Lab
Phase Changes
Photoelectric Effect

8.5.9: Explain how electrical energy can be generated using a variety of energy sources and can be transformed into almost any other form of energy, such as mechanical motion, light, sound, or heat.

Advanced Circuits
Photoelectric Effect

8.5.10: Investigate and explain that in processes at the scale of atomic size or greater, energy cannot be created or destroyed but only changed from one form into another.

Energy Conversion in a System
Energy of a Pendulum
Inclined Plane - Sliding Objects
Period of a Pendulum
Roller Coaster Physics
Simple Harmonic Motion

8.5.11: Compare and contrast how heat energy can be transferred through radiation, convection, or conduction.

Heat Transfer by Conduction

8.6: Electricity and magnetism are related phenomena that have many useful applications in everyday life. As a basis for understanding this concept, students:

8.6.1: Investigate and explain that an object can be electrically charged either positively or negatively; objects with like charges repel each other and objects with unlike charges attract each other.

Coulomb Force (Static)
Element Builder
Pith Ball Lab

8.6.4: Explain that electrical circuits provide a means of transferring electrical energy from sources such as generators to devices in which heat, light, sound, and chemical changes are produced.

Advanced Circuits
Circuits

8.6.5: Know power is energy per unit time, expressed in watts, W, and 1 W = 1 J/s. Explain that devices are rated according to their power capacity or consumption.

Household Energy Usage

8.7: When an object is subject to two or more forces at once, the effective force is the cumulative effect of all the forces. As a basis for understanding this concept, students:

8.7.1: Recognize that a force has both magnitude and direction.

Gravitational Force
Uniform Circular Motion

8.7.2: Observe and explain that when the forces on an object are balanced (equal and opposite forces that add up to zero), the motion of the object does not change.

Atwood Machine
Fan Cart Physics
Pith Ball Lab
Uniform Circular Motion

8.7.3: Explain why an unbalanced force acting on an object changes the object's speed or direction of motion or both.

Atwood Machine
Fan Cart Physics
Inclined Plane - Simple Machine
Roller Coaster Physics
Uniform Circular Motion

8.7.4: Explain that every object exerts an attractive gravitational force on every other object.

Gravitational Force

8.7.5: Know the greater the mass of an object, the more force is needed to change its motion.

Uniform Circular Motion

8.7.6: Explain that the if the net force acting on an object always acts toward the same center as the object moves, the object's path is a curve about the force center. (Motion in a circular orbit is the simplest case of this situation.)

Atwood Machine
Inclined Plane - Simple Machine
Orbital Motion - Kepler's Laws
Pith Ball Lab
Uniform Circular Motion

8.7.7: Graph and interpret distance vs. time graphs for constant speed.

Distance-Time Graphs
Distance-Time and Velocity-Time Graphs

8.8: Waves have characteristic properties that are common to all types of wave. As a basis for understanding this concept, students:

8.8.1: Observe and explain how waves carry energy from one place to another.

Bohr Model of Hydrogen
Bohr Model: Introduction
Photoelectric Effect

8.8.2: Explain how a mechanical wave is a disturbance that propagates through a medium.

Earthquake - Determination of Epicenter
Earthquake - Recording Station

8.8.3: Explain how electromagnetic waves differ from mechanical waves in that they do not need a medium for propagation; nevertheless, they can be described by many of the same quantities: amplitude, wavelength, frequency (or period), and wave speed.

Earthquake - Recording Station

8.8.6: Demonstrate that vibrations in materials set up wave disturbances, such as sound and earthquake waves, that spread away from the source.

Sound Beats and Sine Waves

8.8.7: Recognize that human eyes respond to a narrow range of wavelengths of the electromagnetic spectrum (red through violet) called visible light.

Herschel Experiment
Photoelectric Effect

8.8.8: Summarize how something can be "seen" when light waves emitted or reflected by an object enter the eye just as something can be "heard" when sound waves from it enter the ear.

Laser Reflection

8.8.9: Explain that waves obey the superposition principle: Many waves can pass through the same point at once, and the wave amplitude at that point is the sum of the amplitudes of the individual waves.

Sound Beats and Sine Waves