Teaching the 8th grade Physical Standards: CHEMISTRY
(click here for Grade 5 standards)
3. Each of the more than 100 elements of matter has distinct properties and a distinct atomic structure. As a basis for understanding this concept:
Students know the structure of the atom and know it is composed of protons, neutrons, and electrons.
Students know that compounds are formed by combining two or more different elements, and that compounds have properties that are different from their constituent elements.
Students know atoms and molecules form solids by building up repeating patterns, such as the crystal structure of NaCl or long-chain polymers.
Students know the states of matter (solid, liquid, gas) depend on molecular motion.
Students know that in solids the atoms are closely locked in position and can only vibrate; in liquids the atoms and molecules are more loosely connected and can collide with and move past one another; and in gases the atoms and molecules are free to move independently, colliding frequently.
Students know how to use the periodic table to identify elements in simple compounds.
5. Chemical reactions are processes in which atoms are rearranged into different combinations of molecules. As a basis for understanding this concept:
Students know reactant atoms and molecules interact to form products with different chemical properties.
Students know the idea of atoms explains the conservation of matter: In chemical reactions the number of atoms stays the same no matter how they are arranged, so their total mass stays the same.
Students know chemical reactions usually liberate heat or absorb heat.
Students know physical processes include freezing and boiling, in which a material changes form with no chemical reaction.
Students know how to determine whether a solution is acidic, basic, or neutral.
Chemistry of Living Systems (Life Science)
6. Principles of chemistry underlie the functioning of biological systems. As a basis for understanding this concept:
Students know that carbon, because of its ability to combine in many ways with itself and other elements, has a central role in the chemistry of living organisms.
Students know that living organisms are made of molecules consisting largely of carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur.
Students know that living organisms have many different kinds of molecules, including small ones, such as water and salt, and very large ones, such as carbohydrates, fats, proteins, and DNA.
7. The organization of the periodic table is based on the properties of the elements and reflects the structure of atoms. As a basis for understanding this concept:
Students know how to identify regions corresponding to metals, nonmetals, and inert gases.
Students know each element has a specific number of protons in the nucleus (the atomic number) and each isotope of the element has a different but specific number of neutrons in the nucleus..
Students know substances can be classified by their properties, including their melting temperature, density, hardness, and thermal and electrical conductivity.
8. All objects experience a buoyant force when immersed in a fluid. As a basis for understanding this concept:
Students know density is mass per unit volume.
Students know how to calculate the density of substances (regular and irregular solids and liquids) from measurements of mass and volume.
Students know the buoyant force on an object in a fluid is an upward force equal to the weight of the fluid the object has displaced.
Students know how to predict whether an object will float or sink.
9. Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other three strands, students should develop their own questions and perform investigations. Students will:
Plan and conduct a scientific investigation to test a hypothesis.
Evaluate the accuracy and reproducibility of data.
Distinguish between variable and controlled parameters in a test.
Recognize the slope of the linear graph as the constant in the relationship y=kx and apply this principle in interpreting graphs constructed from data.
Construct appropriate graphs from data and develop quantitative statements about the relationships between variables.
Apply simple mathematical relationships to determine a missing quantity in a mathematic expression, given the two remaining terms (including speed = distance/time, density = mass/volume, force = pressure x area, volume=area x height).
Distinguish between linear and non-linear relationships on a graph of data.