Properties of Matter & Energy
Students will understand the structure and properties of matter, the characteristics of energy and the interactions between matter and energy.
8th Grade students should...
1. Know the forms and properties of matter and how matter interacts.
- Know how to use density, boiling point, freezing point, conductivity and color to identify various substances.
- Distinguish between metals and non-metals.
- Understand the differences among elements, compounds and mixtures by: classification of materials as elements, compounds or mixtures, interpretation of chemical formulas, separation of mixtures into compounds by methods including evaporation, filtration, screening and magnetism.
- Identify the protons, neutrons and electrons within an atom and describe their locations (i.e., in the nucleus or in motion outside the nucleus).
- Explain that elements are organized in the periodic table according to their properties.
- Know that compounds are made of two or more elements, but not all sets of elements can combine to form compounds.
- Know that phase changes are physical changes that can be reversed (e.g., evaporation, condensation, melting).
- Describe various familiar physical and chemical changes that occur naturally (e.g., snow melting, photosynthesis, rusting, burning).
- Identify factors that influence the rate at which chemical reactions occur (e.g., temperature, concentration).
- Know that chemical reactions can absorb energy (endothermic reactions) or release energy (exothermic reactions).
2. Explain the physical processes involved in the transfer, change and conservation of energy.
- Know that energy exists in many forms and that, when energy is transformed, some energy is usually converted to heat.
- Know that kinetic energy is a measure of the energy of an object in motion and potential energy is a measure of an object's position or composition, including transformation of gravitational potential energy of position into kinetic energy of motion by a falling object.
- Distinguish between renewable and non-renewable sources of energy.
- Know that electrical energy is the flow of electrons through electrical conductors that connect sources of electrical energy to points of use, including: electrical current paths through parallel and series circuits, production of electricity by fossil-fueled and nuclear power plants, wind generators, geothermal plants and solar cells, use of electricity by appliances and equipment (e.g., calculators, hair dryers, light bulbs, motors).
- Understand how light and radio waves carry energy through vacuum or matter by: straight-line travel unless an object is encountered, reflection by a mirror, refraction by a lens, absorption by a dark object, separation of white light into different wave lengths by prisms, visibility of objects due to light emission or scattering.
- Understand that vibrations of matter (e.g., sound, earthquakes, water waves) carry wave energy, including: sound transmission through solids, liquids and gases; relationship of pitch and loudness of sound to rate and distance (amplitude) of vibration; ripples made by objects dropped in water.
3. Describe and explain the forces that produce motion in objects.
- Know that there are fundamental forces in nature (e.g., gravity, electromagnetic forces, nuclear forces).
- Know that a force has both magnitude and direction.
- Analyze the separate forces acting on an object at rest or in motion (e.g., gravity, elastic forces, friction), including how multiple forces reinforce or cancel one another to result in a net force that acts on an object.
- Know that electric charge produces electrical fields and magnets produce magnetic fields.
- Know how a moving magnetic field can produce an electric current (generator) and how an electric current can produce a magnetic field (electromagnet).
- Know that earth has a magnetic field.
- Know that an object's motion is always described relative to some other object or point (i.e., frame of reference).
- Understand and apply Newton's laws of motion: objects in motion will continue in motion, and objects at rest will remain at rest, unless acted upon by an unbalanced force (inertia). If a greater force is applied to an object, a proportionally greater acceleration will occur; if an object has more mass, the effect of an applied force is proportionally less.
Students will understand the properties, structures and processes of living things and the interdependence of living things and their environments.
8th grade students should...
1. Explain the diverse structures and functions of living things and the complex relationships between living things and their environments.
- Describe how matter moves through ecosystems (e.g., water cycle, carbon cycle).
- Describe how energy flows through ecosystems (e.g., sunlight, green plants, food for animals).
- Explain how a change in the flow of energy can impact an ecosystem (e.g., the amount of sunlight available for plant growth, global climate change).
2. Understand how traits are passed from one generation to the next and how species evolve.
- Understand that living organisms are made mostly of molecules consisting of a limited number of elements (e.g., carbon, hydrogen, nitrogen, oxygen).
- Identify DNA as the chemical compound involved in heredity in living organisms.
- Describe the widespread role of carbon in the chemistry of living systems.
3. Understand the structure of organisms and the function of cells in living systems.
- Describe how cells use chemical energy obtained from food to conduct cellular functions (i.e., respiration).
- Explain that photosynthesis in green plants captures the energy from the sun and stores it chemically.
- Describe how chemical substances can influence cellular activity (e.g., pH).
Earth, Solar System & Universe
Students will understand the structure of earth, the solar system and the universe, the interconnections among them and the processes and interactions of earth's system.
8th Grade Students Should...
1. Describe how the concepts of energy, matter and force can be used to explain the observed behavior of the solar system, the universe and their structures.
- Understand how energy from the sun and other stars, in the form of light, travels long distances to reach earth.
- Explain how the properties of light (e.g., emission, reflection, refraction) emitted from the sun and stars are used to learn about the universe, including: distances in the solar system and the universe, and temperatures of different stars.
- Understand how gravitational force acts on objects in the solar system and the universe, including similar action on masses on earth and on other objects in the solar system; and explain the orbits of the planets around the sun.
2. Describe the structure of earth and its atmosphere, and explain how energy, matter and forces shape earth's systems.
- Describe the role of pressure and heat in the rock cycle.
- Understand the unique role that water plays on earth, including its ability to remain liquid at most earth temperatures, properties of water related to processes in the water cycle (evaporation, condensation, precipitation, surface run-off, percolation, dissolving of minerals and gases and transport to the oceans, fresh and salt water in oceans, rivers, lakes and glaciers, and reactant in photosynthesis).
- Understand the geologic conditions that have resulted in energy resources (e.g., oil, coal, natural gas) available in New Mexico.