Scientific Method and Concepts Quiz

Historical belief that illness came from bad air.

An ever-changing body of knowledge about nature. A systematic process used to answer questions about the natural world and measurable/observable natural phenomena. NOT the supernatural world. Non-linear, change is slow, skepticism is encouraged, repeatability is a must.

Pure science for knowledge's sake.

Uses basic science to solve specific problems.

Proposed explanation for observations, not a question. They are statements meant to answer specific questions. They are NOT questions. They are NOT "if, then" statements—those are predictions.

Hypotheses cannot be proven true because it is physically impossible to examine all possible cases/scenarios (there is always, a potential alternative hypothesis). Must be testable and falsifiable (able to be proven false).

More specific hypotheses yield clearer experimental results, rules out alternative hypotheses.

Broad explanation supported by multiple hypotheses. Based on many well-supported hypotheses. These hypotheses are supported by data collected by many, independent researchers. As close as we can get to calling something true.

A tool or guide for answering questions/solving problems in science. It is non-linear. You don't have to start in the same place/do all the steps in the same order every time. It is iterative. We repeat it, and sometimes reassess our experimental design. The steps can include: Observing, Questioning, Hypothesizing, Experimenting, Analyzing experimental results, Drawing conclusions.

hypothesis testing. We are usually talking about controlled experiments. They are the best way to test a hypothesis and eliminate alternative hypotheses (controlled experiments can't always be done). They feature independent (manipulated) and dependent (measured) variables, controls (variables kept constant), and methods for minimizing bias.

Manipulated factor in an experiment.

Measured outcome in an experiment.

Group not receiving treatment for comparison/variables kept constants. The more we control, the more potential alternative hypotheses we can eliminate.

When our preconceived notions/preexisting opinions (conscious or unconscious) impact our results; can lead to false conclusions. Minimized through random assignment, single-blind experiments, placebos, and double blind experiments.

Participants randomly assigned to groups, randomly group control and treatment group members.

Patient doesn't know if they are getting memory supplement X or a placebo/sugar pill.

Fake drug that produces no effect given to study participants in the control group instead of the real drug/treatment. To account for the placebo/nocebo effect (you experience symptoms because you think you are going to experience symptoms).

Neither participant nor researcher knows treatment, gold standard in drug studies.

Statistical relationship between two variables, used to predict or describe that there is a relationship. IS NOT CAUSATION.

Determines properties of elements and matter.

Basic building block of matter, consists of protons, neutrons, and electrons

Number of protons in an atom

How much matter there is in an atom and is roughly equal to the number of protons plus the number of neutrons in an atom. Atoms have the same number of protons and electrons

Regions around nucleus where electrons reside. First shell holds 2 electrons, each shell after can hold up to 8

Electrons in the outermost shell of an atom. Atoms with the same number of valence electrons have similar chemical properties.

An atom will strive to achieve a more energetically favorable (stable) state by having 8 electrons in its valence shell.

Atoms will bond with other atoms to share electrons (covalent) or give up or steal electrons (and then form ionic bonds) in order to achieve 8 electrons in their valence shell. In a covalent bond, each atom contributes one electron to a shared electron pair.

Remember that electronegativity is an atom's tendency to attract electrons from another atom and that the most electronegative elements are those which: need only a few electrons to complete their valence (outermost) shells, and have the fewest inner electron shells between the positive nucleus and the valence electrons (in the outermost shell)

Fluorine, Nitrogen, Oxygen, and Chlorine.

Covalent bond in which electrons are shared equally.

Polar bond = covalent bond in which electrons are shared unequally. example is water.

The number of neutrons in an atom can vary. Atoms of an element that differ in the number of neutrons are called isotopes.

Example: Two isotopes of carbon: Carbon-12 (12C) has 6 protons and 6 neutrons Carbon-14 (14C) has 6 protons and 8 neutrons

Number of electrons in the outermost shell. Closer to having 8 valence electrons = higher electronegativity. The size of the atom. The closer the electrons are to the nucleus, the greater the electronegativity. (The fewer electron shells there are between the nucleus and outermost shell) An atom's electronegativity is affected by both its atomic number (how many protons it has) and the size of the atom.

Two or more chemically joined atoms.

Molecule formed by at least two different elements.

Occurs when a highly electronegative atom pulls one or more electrons away from an atom with low electronegatively. Tend to form crystals. Very strong in dry crystal assemblies. Weak in watery environments

Positively charged (+) ions

Negatively charged (-) ions

Ions are atoms that have lost or gained electrons and become charged

Weak interactions between slightly charged atoms. E.g., in a polar covalent bond (like in water) Dipole-dipole interactions important in living systems include: Hydrogen bonds; van der Waals interactions These are weak interactions but, many when many are present the overall effect can be significant. E.g., the structure of the DNA helix is stabilized by hydrogen bonds and van der Waals (and other) forces.

Separation of electrical charges.

A bond between two molecules or two parts of a larger molecule that have specific characteristics. You must have a hydrogen atom bonded to an electronegative atom (N, F, or O) and that bonded pair then interacts with another electronegative atom (N, F, or O).

Are very weak attractions between oppositely charged atoms. The charges on these atoms fleeting. Movement of electrons results in transient, small temporary dipoles. van der Waals are attractions between these dipoles.

Starting Molecules à Ending Molecules. The products are a reconfiguration of the original atoms. First, bonds in the original molecules must be broken. Starting the bond breaking process requires input of energy (called activation energy). Once those original bonds are broken, new bonds form.

Consume water and break complex molecules down into simpler ones: Complex molecule + H2O (reactants) --> simpler molecules (Products) The energy contained in the covalent bonds differs between reactants and products, as does the entropy. No atoms are lost but their arrangement has changed.

Combine simpler molecules together to create a large, more complex molecules and water is released. Simple molecule plus simple molecule (reactants) --> complex molecule and Water (products) Again, the energy contained in the covalent bonds differs between the reactants and the products, as does the entropy. Again, no atoms are lost but their arrangements has changed.

Activation energy (Ea) is the amount of energy needed to get a reaction started. Ea is required because bonds in reactants must first be broken. Molecules are in motion and reactants must be physically close enough to one another to react. Moving reactants in a system collide with one another and these collisions have (kinetic) energy. If the collision has enough energy to overcome the activation energy of a reaction, then those colliding molecules can react with one another.