identify independent and dependent variables
create appropriate axes with labels and scale
identify graph points clearly
choose appropriate measurement scales and use units in recording
show mathematical work, stating formula and steps for solution
use appropriate equations and significant digits
show uncertainty in measurement by the use of significant figures
identify relationships within variables from data tables
calculate percent error
temperature - Celsius (°C), Kelvin (K)
length - kilometers (km), meters (m), centimeters (cm), millimeters (mm)
mass - grams (g), kilograms (kg)
pressure - kilopascal (kPa), atmosphere (atm)
use knowledge of geometric arrangements to predict particle properties or behavior
identify relationships - direct, inverse
apply data showing trends to predict information
state assumptions which apply to the use of a particular mathematical equation and evaluate these assumptions to see if they have been met
evaluate the appropriateness of an answer, based on given data
use theories and/ or models to represent and explain observations
use theories and/ or principles to make predictions about natural phenomena
develop models to explain observations
locate data from published sources to support/ defend/ explain patterns observed in natural phenomena
evaluate the merits of various scientific theories and indicate why one theory was accepted over another
design and/ or carry out experiments, using scientific methodology to test proposed calculations
use library investigations, retrieved information, and literature reviews to improve the experimental design of an experiment
develop research proposals in the form of "if X is true and a particular test Y is done, then prediction Z will occur"
determine safety procedures to accompany a research plan
organize observations in a data table, analyze the data for trends or patterns, and interpret the trends or patterns, using scientific concepts
Apply statistical analysis techniques when appropriate to test if chance alone explains the result.
evaluate experimental methodology for inherent sources of error and analyze the possible effect on the result
compare the experimental result to the expected result; calculate the percent error as appropriate
Using results of the test and through public discussion, revise the explanation and contemplate additional research.
Develop a written report for public scrutiny that describes the proposed explanation, including a literature review, the research carried out, its results, and suggestions for further research.
Initiate and carry out a thorough investigation of an unfamiliar situation and identify needs and opportunities for technological invention or innovation.
Identify, locate, and use a wide range of information resources, and document through notes and sketches how findings relate to the problem.
Generate creative solutions, break ideas into significant functional elements, and explore possible refinements; predict possible outcomes, using mathematical and functional modeling techniques; choose the optimal solution to the problem, clearly documenting ideas against design criteria and constraints; and explain how human understandings, economics, ergonomics, and environmental considerations have influenced the solution.
Develop work schedules and working plans which include optimal use and cost of materials, processes, time, and expertise; construct a model of the solution, incorporating developmental modifications while working to a high degree of quality (craftsmanship).
Devise a test of the solution according to the design criteria and perform the test; record, portray, and logically evaluate performance test results through quantitative, graphic, and verbal means. Use a variety of creative verbal and graphic techniques effectively and persuasively to present conclusions, predict impact and new problems, and suggest and pursue modifications.
use the Internet as a source to retrieve information for classroom use, e.g., Periodic Table, acid rain
critically assess the value of information with or without benefit of scientific backing and supporting data, and evaluate the effect such information could have on public judgment or opinion, e.g., environmental issues
discuss the use of the peer-review process in the scientific community and explain its value in maintaining the integrity of scientific publication, e.g., "cold fusion"
use the concept of systems and surroundings to describe heat flow in a chemical or physical change, e.g., dissolving process
show how models are revised in response to experimental evidence, e.g., atomic theory, Periodic Table
show how information about a system is used to create a model, e.g., kinetic molecular theory (KMT)
show how mathematical models (equations) describe a process, e.g., combine.g.s law
compare experimental results to a predicted value, e.g., percent error
use graphs to make predictions, e.g., half-life, solubility
use graphs to identify patterns and interpret experimental data, e.g., heating and cooling curves
The modern model of the atom has evolved over a long period of time through the work of many scientists.
Each atom has a nucleus, with an overall positive charge, surrounded by negatively charged electrons.
Subatomic particles contained in the nucleus include protons and neutrons.
The proton is positively charged, and the neutron has no charge. The electron is negatively charged.
Protons and electrons have equal but opposite charges. The number of protons equals the number of electrons in an atom.
The mass of each proton and each neutron is approximately equal to one atomic mass unit. An electron is much less massive than a proton or a neutron.
The number of protons in an atom (atomic number) identifies the element. The sum of the protons and neutrons in an atom (mass number) identifies an isotope. Common notations that represent isotopes include: 14 C, 14 C, carbon-14, C-14. 6
In the wave-mechanical model (electron cloud model) the electrons are in orbitals, which are defined as the regions of the most probable electron location (ground state).
Each electron in an atom has its own distinct amount of energy.
When an electron in an atom gains a specific amount of energy, the electron is at a higher energy state (excited state).
When an electron returns from a higher energy state to a lower energy state, a specific amount of energy is emitted. This emitted energy can be used to identify an element.
The outermost electrons in an atom are called the valence electrons. In general, the number of valence electrons affects the chemical properties of an element.
Atoms of an element that contain the same number of protons but a different number of neutrons are called isotopes of that element.
The average atomic mass of an element is the weighted average of the masses of its naturally occurring isotopes.
Stability of an isotope is based on the ratio of neutrons and protons in its nucleus. Although most nuclei are stable, some are unstable and spontaneously decay, emitting radiation.
Spontaneous decay can involve the release of alpha particles, beta particles, positrons, and/ or gamma radiation from the nucleus of an unstable isotope. These emissions differ in mass, charge, ionizing power, and penetrating power.
Matter is classified as a pure substance or as a mixture of substances.
A pure substance (element or compound) has a constant composition and constant properties throughout a given sample, and from sample to sample.
Mixtures are composed of two or more different substances that can be separated by physical means. When different substances are mixed together, a homogeneous or heterogeneous mixture is formed.
The proportions of components in a mixture can be varied. Each component in a mixture retains its original properties.
Elements are substances that are composed of atoms that have the same atomic number. Elements cannot be broken down by chemical change.
Elements can be classified by their properties and located on the Periodic Table as metals, nonmetals, metalloids (B, Si, Ge, As, Sb, Te), and noble gases.
Elements can be differentiated by physical properties. Physical properties of substances, such as density, conductivity, malleability, solubility, and hardness, differ among elements.
Elements can also be differentiated by chemical properties. Chemical properties describe how an element behaves during a chemical reaction.
The placement or location of an element on the Periodic Table gives an indication of the physical and chemical properties of that element. The elements on the Periodic Table are arranged in order of increasing atomic number.
For Groups 1, 2, and 13-18 on the Periodic Table, elements within the same group have the same number of valence electrons (helium is an exception) and therefore similar chemical properties.
The succession of elements within the same group demonstrates characteristic trends: differences in atomic radius, ionic radius, electronegativity, first ionization energy, metallic/ nonmetallic properties.
The succession of elements across the same period demonstrates characteristic trends: differences in atomic radius, ionic radius, electronegativity, first ionization energy, metallic/ nonmetallic properties.
A compound is a substance composed of two or more different elements that are chemically combined in a fixed proportion. A chemical compound can be broken down by chemical means. A chemical compound can be represented by a specific chemical formula and assigned a name based on the IUPAC system.
Compounds can be differentiated by their physical and chemical properties.
Types of chemical formulas include empirical, molecular, and structural.
Organic compounds contain carbon atoms, which bond to one another in chains, rings, and networks to form a variety of structures. Organic compounds can be named using the IUPAC system.
Hydrocarbons are compounds that contain only carbon and hydrogen. Saturated hydrocarbons contain only single carbon-carbon bonds. Unsaturated hydrocarbons contain at least one multiple carbon-carbon bond.
Organic acids, alcohols, esters, aldehydes, ketones, ethers, halides, amines, amides, and amino acids are categories of organic compounds that differ in their structures. Functional groups impart distinctive physical and chemical properties to organic compounds.
Isomers of organic compounds have the same molecular formula, but different structures and properties.
The structure and arrangement of particles and their interactions determine the physical state of a substance at a given temperature and pressure.
The three phases of matter (solids, liquids, and gases) have different properties.
Entropy is a measure of the randomness or disorder of a system. A system with greater disorder has greater entropy.
Systems in nature tend to undergo changes toward lower energy and higher entropy.
Differences in properties such as density, particle size, molecular polarity, boiling and freezing points, and solubility permit physical separation of the components of the mixture.
A solution is a homogeneous mixture of a solute dissolved in a solvent. The solubility of a solute in a given amount of solvent is dependent on the temperature, the pressure, and the chemical natures of the solute and solvent.
The concentration of a solution may be expressed in molarity (M), percent by volume, percent by mass, or parts per million (ppm).
The addition of a nonvolatile solute to a solvent causes the boiling point of the solvent to increase and the freezing point of the solvent to decrease. The greater the concentration of solute particles, the greater the effect.
An electrolyte is a substance which, when dissolved in water, forms a solution capable of conducting an electric current. The ability of a solution to conduct an electric current depends on the concentration of ions.
The acidity or alkalinity of an aqueous solution can be measured by its pH value. The relative level of acidity or alkalinity of these solutions can be shown by using indicators.
On the pH scale, each decrease of one unit of pH represents a tenfold increase in hydronium ion concentration.
Behavior of many acids and bases can be explained by the Arrhenius theory. Arrhenius acids and bases are electrolytes.
Arrhenius acids yield H + (aq), hydrogen ion as the only positive ion in an aqueous solution. The hydrogen ion may also be written as H 3 O + (aq), hydronium ion.
Arrhenius bases yield OH -(aq), hydroxide ion as the only negative ion in an aqueous solution.
In the process of neutralization, an Arrhenius acid and an Arrhenius base react to form a salt and water.
There are alternate acid-base theories. One theory states that an acid is an H + donor and a base is an H + acceptor.
Titration is a laboratory process in which a volume of a solution of known concentration is used to determine the concentration of another solution.
A physical change results in the rearrangement of existing particles in a substance. A chemical change results in the formation of different substances with changed properties.
Types of chemical reactions include synthesis, decomposition, single replacement, and double replacement.
Types of organic reactions include addition, substitution, polymerization, esterification, fermentation, saponification, and combustion.
An oxidation-reduction (redox) reaction involves the transfer of electrons (e -).
Reduction is the gain of electrons.
A half-reaction can be written to represent reduction.
Oxidation is the loss of electrons.
A half-reaction can be written to represent oxidation.
Oxidation numbers (states) can be assigned to atoms and ions. Changes in oxidation numbers indicate that oxidation and reduction have occurred.
An electrochemical cell can be either voltaic or electrolytic. In an electrochemical cell, oxidation occurs at the anode and reduction at the cathode.
A voltaic cell spontaneously converts chemical energy to electrical energy.
An electrolytic cell requires electrical energy to produce a chemical change. This process is known as electrolysis.
Energy can exist in different forms, such as chemical, electrical, electromagnetic, thermal, mechanical, nuclear.
Chemical and physical changes can be exothermic or endothermic.
Energy released or absorbed during a chemical reaction can be represented by a potential energy diagram.
Energy released or absorbed during a chemical reaction (heat of reaction) is equal to the difference between the potential energy of the products and potential energy of the reactants.
Heat is a transfer of energy (usually thermal energy) from a body of higher temperature to a body of lower temperature. Thermal energy is the energy associated with the random motion of atoms and molecules.
Temperature is a measurement of the average kinetic energy of the particles in a sample of material. Temperature is not a form of energy.
The concepts of kinetic and potential energy can be used to explain physical processes that include: fusion (melting), solidification (freezing), vaporization (boiling, evaporation), condensation, sublimation, and deposition.