TEAS scientific reasoning: the 4 skills, with 15 practice questions
Scientific reasoning is one of the four content areas in the TEAS 7 science section, and it has 9 of the section's 44 scored questions. It doesn't ask you to remember facts. It asks you to read a short description of an experiment, a data table or a graph, and decide what it shows: which variable was changed, what the control is, what the data support, which unit fits, and what happens next.
That makes it the most learnable part of TEAS science. This page covers the four skills ATI lists for it, each with a worked example on a small data table, then 15 practice questions with answers and reasons, the mistakes that cost points, and a 10-day plan. Test facts come from ATI's TEAS 7 outline as schools publish it; the examples and questions are ours.
What is scientific reasoning on the TEAS 7?
The TEAS 7 science section has 50 questions in 60 minutes. 44 are scored and 6 are unscored pretest questions you can't tell apart from the rest. The scored questions split like this:
| Science content area | Scored questions | Share of scored science |
|---|---|---|
| Human anatomy and physiology | 18 | 41% |
| Biology | 9 | 20% |
| Scientific reasoning | 9 | 20% |
| Chemistry | 8 | 18% |
Scientific reasoning ties with biology as the second-largest block. Since it needs reading and logic more than memorizing, it's often the quickest place to gain science points when your time is short. If your weak spot is the content itself, start with the TEAS anatomy and physiology topics, which carry twice as many questions.
Not sure which science area is costing you points? Our free TEAS practice test scores each section against your program's minimum, so you can see whether science is the gap before you plan your weeks.
The four scientific reasoning skills ATI tests
ATI's TEAS 7 content outline lists four objectives under scientific reasoning. In plain words:
| Skill (ATI outline) | What the question asks you to do | Typical question |
|---|---|---|
| Use basic scientific measurements and measurement tools | Pick the right tool or unit, convert metric units, read a scale | "Which tool measures 25 mL of liquid most accurately?" |
| Apply logic and evidence to a scientific explanation | Decide which conclusion the data support, spot a claim that goes too far | "Which statement is supported by the results?" |
| Predict relationships among events, objects and processes | Follow cause and effect: if one thing changes, what happens to another | "If the rabbit population drops, what happens to the foxes?" |
| Apply the scientific method to interpret a scientific investigation | Name the hypothesis, the independent and dependent variables, the control; judge the design | "What is the dependent variable in this experiment?" |
The rest of this page takes them in the order that's easiest to learn: the method and its variables first, since every other skill leans on them.
The scientific method, step by step
TEAS questions use the standard steps. You don't need to recite them, but you need to recognize which step a sentence describes.
- Observation: something is noticed. "Seedlings by the window grow taller."
- Question: "Does the amount of light change how tall seedlings grow?"
- Hypothesis: a testable prediction, often "if… then…". "If seedlings get more hours of light, then they will grow taller."
- Experiment: change one thing on purpose, keep everything else the same, measure the result.
- Data and analysis: record the measurements, look for a pattern.
- Conclusion: say whether the data support the hypothesis.
- Repeat or share: others repeat the experiment to check it.
Three words get mixed up on the test:
- A hypothesis is a testable guess about one situation. It can be supported or not supported by data. It's never "proven" by one experiment.
- A theory is a broad explanation backed by many tested results, such as cell theory.
- A law describes what always happens, often as an equation, without saying why (the law of conservation of mass).
A hypothesis must be testable. "Plants prefer classical music" is hard to test as written; "Plants exposed to music for 3 hours a day will grow more in height over 4 weeks than plants kept in silence" can be measured.
Independent, dependent and controlled variables
Most scientific reasoning questions come back to variables. Learn these three until you can name them in a few seconds.
| Variable | What it is | Ask yourself | Where it goes on a graph |
|---|---|---|---|
| Independent | The one thing the researcher changes on purpose | "What did they change?" | x-axis (horizontal) |
| Dependent | What is measured as a result | "What did they measure?" | y-axis (vertical) |
| Controlled (constants) | Everything kept the same so the test is fair | "What stayed the same?" | Not graphed |
A control group is different from a controlled variable. The control group gets no treatment (or the standard one), so you have something to compare against. A confounding variable is something that wasn't kept the same and could explain the result instead.
Worked example: water temperature and dissolving time
A student drops one sugar cube into 200 mL of water at four temperatures and times how long it takes to dissolve. Same cup, same stirring, same cube size.
| Water temperature (°C) | Time to dissolve (seconds) |
|---|---|
| 10 | 210 |
| 30 | 140 |
| 50 | 85 |
| 70 | 50 |
- Independent variable: water temperature (the student set it).
- Dependent variable: time to dissolve (the student measured it).
- Controlled variables: volume of water, cube size, cup, stirring.
- The trend: as temperature rises, dissolving time falls. That's an inverse relationship.
- A supported conclusion: in this test, sugar dissolved faster in warmer water. Not supported: "heat always speeds up every reaction", which goes beyond the data.
If the student had stirred the warm cups and not the cold ones, stirring would be a confounding variable: you couldn't tell whether temperature or stirring made the difference.
What makes an experiment fair: controls, sample size and repeats
"Which change would improve this experiment?" is a common question. The answer is nearly always one of these:
- Change one variable at a time. If two things change together, you can't say which caused the result.
- Add a control group. A drug trial with no placebo group can't show the drug did better than nothing.
- Use a bigger sample. Three plants can differ by chance; thirty are less likely to mislead.
- Repeat the trials. Repeating and averaging reduces the effect of one odd result.
- Randomize and blind. Randomly assigning subjects avoids picking healthier people for the treatment group; blinding stops expectations from changing results.
Two more pairs show up often:
| Term | Meaning | Example |
|---|---|---|
| Accurate | Close to the true value | A scale reads 100.1 g for a 100 g weight |
| Precise | Repeated readings close to each other | Readings of 92.4, 92.5, 92.4 g (precise, but not accurate if the true value is 100 g) |
| Reliable | Gives the same result when repeated | Three trials give nearly the same time |
| Valid | Measures what it claims to measure | Measuring plant height to judge growth, not leaf color |
Measurements, units and tools
The TEAS uses the metric system (SI) in science. You need the base units, the common prefixes, and which tool measures what.
| Quantity | Base unit | Tool |
|---|---|---|
| Length | meter (m) | ruler, meter stick |
| Mass | gram (g); SI base is the kilogram | balance (triple beam or electronic) |
| Volume of a liquid | liter (L) | graduated cylinder, pipette, buret |
| Temperature | degrees Celsius (°C); SI base is the kelvin | thermometer |
| Time | second (s) | stopwatch |
| Prefix | Symbol | Factor | Example |
|---|---|---|---|
| kilo- | k | 1,000 | 1 km = 1,000 m |
| (base) | 1 | 1 m, 1 g, 1 L | |
| deci- | d | 0.1 | 1 dL = 0.1 L |
| centi- | c | 0.01 | 1 cm = 0.01 m |
| milli- | m | 0.001 | 1 mL = 0.001 L |
| micro- | µ | 0.000001 | 1 µg = 0.000001 g |
Converting: moving to a smaller unit, multiply (the number gets bigger); moving to a larger unit, divide. 2.5 L to mL: 2.5 × 1,000 = 2,500 mL. 450 mg to g: 450 ÷ 1,000 = 0.45 g. One milliliter equals one cubic centimeter (1 mL = 1 cm³).
Temperature: K = °C + 273 (273.15 exactly). °F = (°C × 9/5) + 32, so 37 °C is 98.6 °F. Water freezes at 0 °C and boils at 100 °C at sea level.
Reading a graduated cylinder: read at eye level from the bottom of the curved surface (the meniscus). Pick the smallest tool that holds the amount: 8 mL is measured more precisely in a 10 mL cylinder than a 100 mL one.
Choosing a sensible unit: report a pill's mass in milligrams, a person's in kilograms, a cell's width in micrometers. A question that offers "an apple weighs about 150 kg" wants you to notice the unit is wrong.
For the conversion facts in one place, the TEAS math formulas and conversion chart has the full table; the math and science sections use the same metric rules.
Reading data tables and graphs
Several scientific reasoning questions give you data and ask what it shows. Read the title, the axis labels and the units before the numbers.
| Graph type | Best for |
|---|---|
| Line graph | A change over time or across a range (temperature over a day) |
| Bar graph | Comparing separate groups (heart rate in four age groups) |
| Pie chart | Parts of one whole that add to 100% (blood types in a sample) |
| Scatter plot | Whether two measured things move together (height and shoe size) |
Worked example: exercise and heart rate
| Minutes of brisk walking | Average heart rate (beats per minute) |
|---|---|
| 0 | 70 |
| 5 | 95 |
| 10 | 110 |
| 15 | 118 |
| 20 | 120 |
What it shows: heart rate rises with walking time, fast at first (25 beats in the first 5 minutes) then slowly (2 beats from 15 to 20). It levels off, so predicting about 120 to 122 at 25 minutes fits the data; predicting 145 does not. This is reading a trend and extending it carefully, which ATI calls predicting relationships.
Note what the data can't tell you: the table doesn't show why heart rate rises, or what happens to people of other fitness levels, unless the description says who was tested.
Logic and evidence: correlation, causation and supported conclusions
"Which conclusion is best supported?" questions reward caution. The right answer says what the data show, about the group tested, and no more.
- Correlation is not causation. Ice cream sales and sunburns rise together, but ice cream doesn't cause sunburn; hot sunny weather drives both. Only a controlled experiment, where one variable is changed and others held steady, can point to cause.
- Watch absolute words. Answers with "always", "never", "proves" or "all" are usually wrong; one experiment supports or fails to support.
- Stay inside the sample. A study of 20 adults doesn't tell you about children.
- Deductive reasoning goes from a general rule to a specific case: all mammals have hair; a whale is a mammal; so a whale has hair. Inductive reasoning goes from observations to a general rule: every swan I've seen is white, so swans are white. Induction can be overturned by one new observation.
- Evidence vs. opinion. Measured results are evidence. "Most people believe" is not.
Predicting relationships among events and processes
These questions ask what happens to one thing when another changes. They draw on everyday biology, chemistry and physics, so a little content helps:
- Food chains: grass → rabbits → foxes. If rabbits decline, foxes have less food and decline later; grass may grow more.
- Direct relationship: both rise together (more light, more photosynthesis, up to a limit).
- Inverse relationship: one rises as the other falls (higher altitude, lower air pressure).
- Feedback in the body: blood sugar rises after a meal, insulin is released, blood sugar falls. The anatomy and physiology guide covers these systems.
- Chemistry: raising temperature usually speeds up a reaction; the TEAS chemistry review covers reaction rates and solutions.
TEAS scientific reasoning practice questions
15 questions. Give yourself about 18 minutes, the science section's pace of 72 seconds a question. Answers and reasons follow.
- A researcher gives three groups of mice 0, 5 and 10 mg of a vitamin daily and measures their weight after 4 weeks. What is the independent variable?
A. Mouse weight B. Number of mice C. Vitamin dose D. Length of the study - In question 1, what is the dependent variable?
A. Mouse weight B. Type of food C. Vitamin dose D. Cage size - Which group in question 1 is the control group?
A. 10 mg B. 5 mg C. 0 mg D. There is none - Which tool should be used to measure 18 mL of saline most precisely?
A. 250 mL beaker B. 25 mL graduated cylinder C. 100 mL graduated cylinder D. 1 L flask - Convert 0.75 L to milliliters.
A. 7.5 mL B. 75 mL C. 750 mL D. 7,500 mL - Which hypothesis can be tested?
A. Cats are better pets than dogs. B. Plants given fertilizer weekly will grow taller in 6 weeks than plants given none. C. Music makes plants happy. D. Science is the most important subject. - A student tests whether salt changes the boiling point of water but uses a different pot and burner for each sample. What is the main problem?
A. Too many samples B. Uncontrolled variables C. No hypothesis D. The wrong units - A survey finds that people who drink more coffee report fewer headaches. Which conclusion is supported?
A. Coffee prevents headaches. B. Headaches cause less coffee drinking. C. Coffee drinking and fewer reported headaches are linked in this group. D. Everyone should drink coffee. - A balance reads 49.1 g, 49.2 g and 49.1 g for an object that truly weighs 52.0 g. The readings are:
A. Accurate and precise B. Precise but not accurate C. Accurate but not precise D. Neither - Body temperature is 37 °C. What is it in kelvin, to the nearest whole number?
A. 236 B. 273 C. 310 D. 337 - Which graph best shows how a patient's temperature changed over 24 hours?
A. Pie chart B. Line graph C. Bar graph of blood types D. Venn diagram - In a pond, algae are eaten by small fish, which are eaten by herons. A chemical kills most of the algae. What is the most likely first effect?
A. Herons increase B. Small fish decrease C. Algae increase D. Nothing changes - A drug trial gives the new drug to 15 volunteers who choose to join. Which change would most improve it?
A. Fewer volunteers B. A randomly assigned placebo group and more volunteers C. Telling everyone which pill they get D. Ending the trial early - Every metal a student tests conducts electricity, so she concludes all metals conduct electricity. This is:
A. Deductive reasoning B. Inductive reasoning C. A controlled variable D. A law - Gas volume is measured at 1, 2 and 4 atmospheres of pressure: 12 L, 6 L, 3 L, temperature held steady. What relationship does this show?
A. Direct B. Inverse C. No relationship D. Random
Answers and reasons
| # | Answer | Why |
|---|---|---|
| 1 | C | The dose is what the researcher sets on purpose. |
| 2 | A | Weight is what's measured as the result. |
| 3 | C | The 0 mg group gets no treatment, the baseline for comparison. |
| 4 | B | Use the smallest tool that holds the amount; beakers and flasks aren't for precise volumes. |
| 5 | C | L to mL is × 1,000: 0.75 × 1,000 = 750. |
| 6 | B | It names a change, a measure and a time frame, so data can support it or not. |
| 7 | B | Pot and burner change along with salt, so they could explain the result. |
| 8 | C | A survey shows a link, not a cause, and only for the people asked. |
| 9 | B | The readings agree with each other (precise) but are about 3 g off the true value (not accurate). |
| 10 | C | 37 + 273 = 310. |
| 11 | B | A line graph shows change over time. |
| 12 | B | The small fish lose their food first; the herons feel it later. |
| 13 | B | Random assignment, a placebo comparison and a bigger sample remove the main biases. |
| 14 | B | She moved from specific observations to a general rule. |
| 15 | B | Pressure doubles, volume halves: as one rises the other falls. |
13 or more right: this area is likely a strength; spend your science time on anatomy and physiology. 9 to 12: drill variables and conclusions for a few days. Under 9: work through the plan below. For mixed science practice in the test's spread, try the TEAS science practice test with 20 free questions.
Common scientific reasoning mistakes
- Swapping the variables. Fix it with one question each time: "What did they change?" That's independent.
- Calling constants "the control". Controlled variables are kept the same; the control group is the untreated group.
- Picking the boldest conclusion. The best-supported answer is usually the most modest one.
- Skipping the units. Read axis labels first. A graph in mg and an answer in g can trap you.
- Converting the wrong way. Smaller unit, bigger number. Check that the size of your answer makes sense.
- Using outside knowledge over the data. If the question says "based on the results", answer from the table, even if you know a different fact.
- Spending too long. At 72 seconds a question, a data question you can't crack in 90 seconds gets a best guess and a flag. Unanswered questions count as wrong, so never leave one blank.
A 10-day scientific reasoning study plan
About 20 to 30 minutes a day. Fit it beside your anatomy work, since anatomy carries more questions.
| Day | Focus | Do this |
|---|---|---|
| 1 | Scientific method | Write the 7 steps from memory; label 5 sentences by step. |
| 2 | Variables | For 10 short experiments, name independent, dependent and 2 constants. |
| 3 | Controls and fair tests | For 5 flawed experiments, write the one change that fixes each. |
| 4 | Metric prefixes | Learn the prefix table; do 20 conversions, checking each answer's size. |
| 5 | Tools and temperature | Match 10 quantities to tools; convert 5 temperatures to K and °F. |
| 6 | Tables and graphs | Describe the trend in 5 data tables in one sentence each. |
| 7 | Conclusions | For each table, write one supported and one unsupported conclusion. |
| 8 | Relationships | Food chains, direct and inverse pairs, body feedback loops. |
| 9 | Timed practice | Redo the 15 questions above cold, timed at 18 minutes. |
| 10 | Mixed science | A full timed science set; review every miss and name the skill it tested. |
For the order across all four science areas, see how to study for the TEAS science section, which puts scientific reasoning in its two-week plan, and the TEAS biology review for the other 9-question block.
TEAS scientific reasoning FAQ
How many scientific reasoning questions are on the TEAS 7?
9 scored questions, out of 44 scored in science. Some of the section's 6 unscored pretest questions may also be on scientific reasoning, but you can't tell which.
Is scientific reasoning hard on the TEAS?
It's mostly careful reading, not memorizing. Once you can name variables and controls quickly and read a table's units, most questions take under a minute.
Do I need to memorize formulas for scientific reasoning?
Not many. Know the metric prefixes, K = °C + 273, and the °C to °F conversion. Calculations are short enough to work on scratch paper.
Is physics part of scientific reasoning?
Under TEAS 7, the four scored areas are anatomy and physiology, biology, chemistry and scientific reasoning. Simple physics ideas such as pressure, force or motion can appear inside a reasoning question as the experiment being described.
What is the best way to practice TEAS scientific reasoning questions?
Timed sets of short experiments and data tables, with the reason for each miss written down. Name the skill each missed question tested, then drill that skill.
Sources
- ATI, ATI TEAS exam details (science: 50 questions, 60 minutes, content areas for Version 7).
- Western Technical College library, ATI TEAS Version 7 test structure (science: 18 anatomy and physiology, 9 biology, 8 chemistry, 9 scientific reasoning, 6 unscored pretest).
- Bucks County Community College, ATI TEAS content outline (the scientific reasoning objectives).
- ATI, ATI TEAS sections and going back to a question (unanswered questions scored as wrong).
- NIST, Metric (SI) prefixes.
Next, see where science sits against your other sections with our free TEAS practice test, or browse all TEAS guides.