Scientific Inquiry and Reasoning Skills 1 and 2
The same four skills are weighted identically on all three science sections, and reasoning outweighs knowledge on every one of them.
10 topics · 41 questions
Each topic is a path, not a menu: work down it in order and every question builds on the one above. Click any of them to watch the answer draw itself.
The Four Skills and Their 35/45/10/10 Weights
- How it worksHow do the four scientific inquiry skills divide 35, 45, 10 and 10 percent of every science section?
- Worked exampleFind how many of a 59-question science section are pure recall when Skill 1 accounts for 35 percent of it.
- Common mistakeWhy isn't memorising more content the fastest way to raise a science section score from 125 to 129?
- Going furtherWhat changes about your studying when 45 percent of the questions reward reasoning you cannot flashcard?
Your turneasy1 of 3
A student has 62 hours of study left and divides them in proportion to the SIRS weights, so Skill 1 gets its 35 percent share and Skill 2 its 45 percent. How many more hours does Skill 2 receive than Skill 1?Skill 1: Knowledge of Scientific Concepts and Principles
- How it worksHow does Skill 1 test recognising, identifying, recalling and defining a concept in four different ways?
- Common mistakeWhy doesn't recognising a concept written in words guarantee you will recognise it drawn as a graph?
- Worked exampleWalk me through recognising extinction from a rat that stops pressing a lever once no food ever follows.
- Going furtherWhat changes when a Skill 1 question asks for the relationship between two closely related concepts?
Your turneasy1 of 3
A rat presses a lever that has delivered food on 51 of its first 99 presses. The experimenter disconnects the dispenser. Over the next 99 trials the rate of pressing falls to near zero. Question: which term names what has happened?Written, Symbolic and Graphic Forms of One Concept
- How it worksHow do you move between a sentence, a formula and a curve that all describe the very same relationship?
- Worked exampleWalk me through matching rate doubles when concentration doubles to a straight line through the origin.
- Worked exampleWalk me through turning a titration curve back into the sentence describing what happens inside the flask.
- Common mistakeWhy isn't a graph simply a picture of an equation you have already memorised?
- Going furtherWhat changes when the same measurements are redrawn with a logarithmic axis instead of a linear one?
Your turneasy1 of 3
A reaction is first order in A: the rate doubles when the concentration of A doubles. Plotted as rate against concentration, the line passes through the origin. If the rate is 15 millimolar per second when A is 7 millimolar, what is the slope of that line?Observations That Illustrate a Principle
- How it worksHow do you strip the unfamiliar surface off an observation to see which principle is actually running it?
- Worked exampleWalk me through identifying which principle explains a protein that refolds correctly after urea is washed out.
- Common mistakeWhy doesn't a result that looks like a principle always come from that principle?
Your turneasy1 of 3
A protein is denatured in 7 molar urea and loses all activity. The urea is dialysed away over 18 hours and activity returns to near its original level. Question: which principle does this observation illustrate?Using an Equation the Passage Hands You
- How it worksHow do you read an unfamiliar equation for what each symbol does before you put a single number in?
- Worked exampleFind the flow rate from Q equals delta P over R when delta P is 80 mmHg and R is 20 mmHg per unit flow.
- Worked exampleWalk me through using a supplied equation when one variable doubles and you need only the ratio, not the value.
- Going furtherWhat changes when a supplied equation contains a term the question tells you is negligible?
Your turneasy1 of 3
A passage supplies Q = delta P over R for flow through a vessel. If delta P is 96 mmHg and R is 21 mmHg per unit of flow, what is Q?Skill 2: Scientific Reasoning and Problem-Solving
- How it worksHow does a Skill 2 question take a principle you know and put it to work on a situation you have never met?
- Worked exampleWalk me through predicting what happens to an enzyme's rate when the pH around it drops from 7.4 to 5.0.
- Common mistakeWhy isn't a Skill 2 question answerable by hunting for the matching sentence in the text?
- Going furtherWhat changes when a Skill 2 question gives you a model that conflicts with the one you learned in class?
Your turnhard1 of 3
An enzyme with optimum activity at pH 7.4 is moved into a compartment at pH 5. Its substrate binding depends on a histidine residue with a side-chain pKa near 7. Question: what should happen to the rate?Judging the Credibility of an Explanation
- How it worksHow do you test an explanation against the evidence it rests on rather than against how sensible it sounds?
- Common mistakeWhy doesn't an explanation offered by the researchers themselves get extra credibility on the MCAT?
- Worked exampleWalk me through judging the drug works because patients felt better when there was no comparison group.
- Going furtherWhat changes about an explanation's credibility when it predicts something nobody has measured yet?
Your turneasy1 of 3
A report states that after 151 patients received the drug, 74 percent said they felt better, and concludes that the drug works. No untreated group was followed. Question: what is the central weakness?Evaluating Arguments About Cause and Effect
- How it worksHow do temporality, a plausible mechanism and random assignment each lift a claim from association to cause?
- Worked exampleWalk me through evaluating coffee drinkers live longer, so coffee extends life, from a cohort study.
- Common mistakeWhy doesn't a correlation of 0.9 get you any closer to a causal claim than a correlation of 0.4?
- Going furtherWhat changes about a causal argument when the proposed cause and effect could run in either direction?
- Ties togetherHow does the cause-and-effect test on a science passage connect to spotting a confound in a study design?
Your turnmedium1 of 3
A cohort of 69 thousand adults is followed for 19 years. Those drinking coffee daily die at a lower rate, and the report concludes that coffee extends life. Question: what is the strongest objection?Turning Theory, Model and Observation into a Prediction
- How it worksHow do you combine a theory, a model and a table of observations into one prediction the evidence supports?
- Worked exampleWalk me through predicting the effect on oxygen delivery when a right shift appears in the binding curve.
- Going furtherWhat happens to a prediction when the theory and the observations point in opposite directions?
- Common mistakeWhy isn't the prediction that fits your intuition the one the MCAT wants when a model says otherwise?
Your turnmedium1 of 3
A passage supplies an oxygen binding curve and reports that in exercising muscle the curve shifts right, with the partial pressure at half saturation moving from 27 to 38 mmHg. Question: what is the predicted effect on oxygen delivery to that tissue?Findings That Challenge or Invalidate a Theory
- How it worksHow do you work out what a theory forbids, so you can recognise the observation that would break it?
- Worked exampleWalk me through which result would invalidate the claim that a channel is voltage-gated rather than ligand-gated.
- Common mistakeWhy doesn't a result that a theory failed to predict automatically invalidate that theory?
- Going furtherWhat changes when a finding challenges only one part of a model and leaves the rest of it standing?
Your turnmedium1 of 3
A channel is claimed to be voltage-gated. Recordings show it opens when the membrane is depolarised from -76 to -21 millivolts. Question: which further result would most damage the claim?AP®, SAT® and PSAT/NMSQT® are trademarks registered by the College Board (PSAT/NMSQT® jointly with the National Merit Scholarship Corporation). ACT® is a registered trademark of ACT Education Corp. GRE® is a registered trademark of ETS. LSAT® is a registered trademark of the Law School Admission Council. MCAT® is a registered trademark of the Association of American Medical Colleges. ISEE® and SSAT® are registered trademarks of their owners. None of these organizations is affiliated with, or endorses, Jentoo.