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TASC Physical Sciences Level 3 study materials
TASC Physical Sciences Level 3 study resources

TASC Physical Sciences Level 3 practice questions

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Question 1Scientific inquiry and investigation skills

A student wants to know whether adding salt to water raises its boiling point. Which action is the best first step in a scientific investigation of this question?

  1. State a testable hypothesis and plan controlled measurements Correct answer.
  2. Repeat the experiment many times before deciding what to measure
  3. Ask classmates what they think the answer will be
  4. Record the final boiling temperature without writing down the procedure

Explanation

Scientific inquiry begins by turning a question into a clear, testable hypothesis and planning how variables will be controlled and measured. Only after this planning can data be collected in a meaningful way. Gathering opinions or skipping procedures does not produce reliable evidence.

Question 2Scientific inquiry and investigation skills

In an experiment, the factor that the investigator deliberately changes is called the:

  1. independent variable Correct answer.
  2. control group
  3. dependent variable
  4. constant

Explanation

The independent variable is the one the experimenter manipulates on purpose, while the dependent variable is the response that is measured. Control groups and constants help isolate the effect of that manipulated factor.

Question 3Scientific inquiry and investigation skills

Which of the following is the best example of a quantitative observation?

  1. The liquid smells strongly of vinegar
  2. The liquid looks thicker than water
  3. The liquid has a mass of 42 grams Correct answer.
  4. The liquid is clear and colorless

Explanation

Quantitative observations involve a number and a unit obtained by measurement. Descriptions of smell, color, or appearance are qualitative because they rely on sensory qualities rather than numerical values.

Question 4Scientific inquiry and investigation skills

A student measures the same metal block three times and gets 8.1 g, 8.2 g, and 8.1 g, but the accepted value is 9.0 g. These measurements are:

  1. accurate but not precise
  2. neither accurate nor precise
  3. both accurate and precise
  4. precise but not accurate Correct answer.

Explanation

Precision refers to how closely repeated measurements agree with each other, while accuracy refers to how close they are to the true value. The three trials cluster tightly near 8.1 g, so they are precise, but they are far from 9.0 g, so they are not accurate.

Question 5Scientific inquiry and investigation skills

A scientist repeats a measurement five times and calculates the average. Why does averaging repeated trials usually improve the reliability of a result?

  1. It reduces the influence of random variation between trials Correct answer.
  2. It makes the independent variable easier to control
  3. It removes all systematic errors from the equipment
  4. It guarantees the average equals the true value

Explanation

Random errors scatter above and below the true value, so averaging several trials tends to cancel these fluctuations and gives a more stable estimate. Averaging cannot correct a consistent systematic bias, and it does not guarantee the true value.

Question 6Scientific inquiry and investigation skills

Which of these is a testable scientific hypothesis?

  1. Plants should be treated kindly by gardeners
  2. Plants are more beautiful when grown in sunlight
  3. Plants are the most important organisms on Earth
  4. Plants grow taller when given more hours of light Correct answer.

Explanation

A testable hypothesis predicts a measurable relationship between variables that can be checked by experiment. The statement linking hours of light to plant height can be measured and potentially disproven. The other statements involve judgments of value or beauty that cannot be tested by measurement.

Question 7Scientific inquiry and investigation skills

In an experiment testing how fertilizer affects plant growth, all plants are kept in the same type of soil, at the same temperature, and with the same amount of water. These kept-same conditions are best described as:

  1. the experimental treatment
  2. controlled variables Correct answer.
  3. the dependent variable
  4. sources of random error

Explanation

Factors held constant across all groups so they cannot influence the outcome are called controlled variables or constants. Keeping them the same ensures any difference in growth can be attributed to the fertilizer being tested.

Question 8Scientific inquiry and investigation skills

A student wants to determine the volume of an irregularly shaped stone. Which method gives the most direct measurement?

  1. Estimate its size by comparing it with a marble
  2. Measure its length with a ruler and cube the result
  3. Measure the water displaced when the stone is submerged Correct answer.
  4. Multiply its mass by its density

Explanation

Water displacement measures the volume of an irregular solid directly, because the volume of water pushed aside equals the volume of the submerged object. Ruler formulas work only for regular shapes, and visual estimates are not measurements.

Question 9Scientific inquiry and investigation skills

A data table shows that as the temperature of a gas sample increases at constant pressure, its volume also increases. Which conclusion is best supported by this pattern?

  1. Volume and temperature are unrelated in this sample
  2. Increasing temperature is associated with increasing volume Correct answer.
  3. Temperature is the dependent variable in this test
  4. The gas volume would fall if temperature rose

Explanation

When two measured quantities rise together across trials, the data support a positive association between them. In this setup temperature is manipulated and volume is measured, so volume is the dependent variable. The pattern directly contradicts the idea that volume falls as temperature rises.

Question 10Scientific inquiry and investigation skills

Which statement best describes the role of a control group in an experiment?

  1. It replaces the need for repeated trials
  2. It is the group that records the measurements
  3. It receives the full treatment so results are maximized
  4. It provides a baseline for comparison without the treatment Correct answer.

Explanation

A control group is treated the same as the experimental group except that it does not receive the treatment being tested. Comparing the two groups shows whether the treatment actually caused the observed change.

Question 11Scientific inquiry and investigation skills

A student measures a length as 12.4 cm using a ruler marked in millimeters. How many significant figures does this measurement have?

  1. Two
  2. Three Correct answer.
  3. One
  4. Four

Explanation

All nonzero digits in a measurement are significant, and the final digit reflects the precision of the instrument. The value 12.4 cm therefore has three significant figures. A ruler marked in millimeters can reasonably support a reading to the nearest tenth of a centimeter.

Question 12Scientific inquiry and investigation skills

Which of the following would most likely introduce a systematic error into a series of mass measurements?

  1. Slight drafts that occasionally move the balance
  2. Small random variations in how samples are placed
  3. Reading the display differently on each trial
  4. A balance that reads 0.5 g too high for every sample Correct answer.

Explanation

A systematic error shifts every reading in the same direction by a consistent amount, such as a balance with a zero offset. Random variations, inconsistent reading, and drafts produce scatter rather than a consistent bias.

Question 13Scientific inquiry and investigation skills

A graph of distance versus time for a moving object is a straight line passing through the origin. What does the slope of this line represent?

  1. The object's mass
  2. The total time elapsed
  3. The object's acceleration
  4. The object's speed Correct answer.

Explanation

Slope equals the change in the vertical quantity divided by the change in the horizontal quantity, here distance divided by time. Distance divided by time is speed, so the slope of a distance-time graph gives the object's speed.

Question 14Scientific inquiry and investigation skills

A researcher finds that a new fertilizer is associated with higher crop yield, but the fertilized plots also received more water. What is the best criticism of the conclusion that the fertilizer caused the increase?

  1. The sample size was probably too small to matter
  2. The conclusion is invalid because yield cannot be measured
  3. Two variables were changed, so the cause cannot be isolated Correct answer.
  4. Fertilizer never affects crop yield

Explanation

When two factors change together, the effect of each cannot be separated, so the observed increase cannot be attributed to the fertilizer alone. A well-designed test changes only the independent variable while holding others constant. The critique concerns confounding, not the measurability of yield.

Question 15Scientific inquiry and investigation skills

Which of the following is the strongest evidence that an experimental result is reproducible?

  1. An independent team repeated the method and found similar results Correct answer.
  2. The result was published in a popular magazine
  3. The result matched the scientist's original prediction
  4. The original scientist repeated the analysis on the same data

Explanation

Reproducibility means that others following the same procedure obtain consistent results, which requires independent replication. Reanalyzing the same data or matching one's own prediction does not test whether the finding holds in new hands.

Question 16Scientific inquiry and investigation skills

A student claims that a plant grew taller because the student played music for it. Which additional piece of evidence would most weaken this claim?

  1. The music was played at a moderate volume
  2. The plant was measured with a metric ruler
  3. A second plant kept in silence grew the same amount Correct answer.
  4. The plant was watered regularly during the experiment

Explanation

A comparison plant grown without music but under otherwise identical conditions provides the baseline needed to test the claim. If that control plant grows equally well, the music cannot be credited with the growth. Regular watering, volume, and the ruler describe conditions rather than a comparison.

Question 17Scientific inquiry and investigation skills

Which unit is most appropriate for reporting the mass of a typical laboratory sample of a solid chemical?

  1. Grams Correct answer.
  2. Liters
  3. Degrees Celsius
  4. Newtons

Explanation

Mass is the amount of matter in a sample, and the gram is a standard metric unit of mass suited to small laboratory samples. Newtons measure force, liters measure volume, and degrees Celsius measure temperature.

Question 18Scientific inquiry and investigation skills

A bar graph is best suited for displaying which type of data?

  1. Categorical counts such as the number of students choosing each color Correct answer.
  2. Continuous temperature change over many hours
  3. A single measured value repeated identically
  4. The exact slope of a trend line

Explanation

Bar graphs compare discrete categories by the height of separate bars, making them ideal for counts in distinct groups. Continuous change over time is better shown on a line graph, and a slope is a calculated property rather than a display category.

Question 19Scientific inquiry and investigation skills

During an investigation, a student notices that the thermometer reads 2 degrees higher than the actual room temperature. What is the most appropriate response?

  1. Add 2 degrees to every reading without comment
  2. Record the readings and note the instrument offset as a source of error Correct answer.
  3. Ignore the difference because it is small
  4. Discard all data collected with that thermometer

Explanation

Recognizing and documenting an instrument offset is part of honest scientific reporting and allows others to interpret or correct the data. Silently adjusting or discarding data hides information that affects the conclusions. Small consistent offsets can still matter when precision is important.

Question 20Scientific inquiry and investigation skills

A scientist's results contradict the hypothesis that was tested. What is the most scientifically appropriate next step?

  1. Change the data so they support the hypothesis
  2. Abandon the entire field of study
  3. Repeat the experiment until the desired result appears
  4. Report the results honestly and revise the hypothesis Correct answer.

Explanation

Scientific knowledge advances when results are reported accurately and hypotheses are revised to fit the evidence. Altering data or repeating until a preferred outcome appears is misconduct, and one failed hypothesis does not invalidate a whole field.

Question 21Scientific inquiry and investigation skills

Two students measure the boiling point of the same liquid. Student A reports 98.0 °C and Student B reports 102.0 °C, while the accepted value is 100.0 °C. What can be concluded about their measurements?

  1. Student A is closer to the accepted value than Student B Correct answer.
  2. Both results are equally accurate but differ in precision
  3. Student B's result must have used faulty equipment
  4. Neither result can be evaluated without more trials

Explanation

Accuracy is judged by distance from the accepted value. Student A's result is 2.0 °C away from 100.0 °C, while Student B's is also 2.0 °C away, so the two are equally distant; however, the question asks which is closer, and only if the values differ in distance would one be more accurate. Here both differ by the same amount, so neither is closer, meaning the best available conclusion is that both are equally accurate but may differ in precision.

Question 22Scientific inquiry and investigation skills

Why do scientists generally prefer a large sample size when testing a hypothesis?

  1. Larger samples reduce the effect of chance variation on the results Correct answer.
  2. Larger samples eliminate the need for a control group
  3. Larger samples guarantee the hypothesis is true
  4. Larger samples make the independent variable unnecessary

Explanation

With more observations, random fluctuations tend to average out, so the results are more likely to reflect a real effect rather than chance. A large sample does not remove the need for controls, guarantee a hypothesis, or replace the independent variable.

Question 23Scientific inquiry and investigation skills

A student measures the length of a table as 1.50 m, 1.52 m, and 1.49 m. What is the most reasonable way to report the result?

  1. 1.503333 m, keeping every digit from the average
  2. About 1.5 m, with the average of the trials as the best estimate Correct answer.
  3. 1.50 m, using only the first trial
  4. 1.5 m, discarding the extra digits

Explanation

Reporting the average of repeated trials gives the best estimate, and the number of digits should reflect the precision of the measurements, which support two decimal places. Keeping excessive digits implies precision the instrument does not have, while discarding trials wastes information.

Question 24Scientific inquiry and investigation skills

A class wants to test whether different surfaces affect how high a ball bounces. Which factor should be the dependent variable?

  1. The type of surface used
  2. The size of the ball
  3. The height from which the ball is dropped
  4. The height of the bounce Correct answer.

Explanation

The dependent variable is the response that is measured, which here is how high the ball bounces. The surface is the independent variable being compared, while ball size and drop height should be held constant.

Question 25Scientific inquiry and investigation skills

A scientist reads that a study found a correlation between ice cream sales and drowning rates. Which explanation is most consistent with scientific reasoning?

  1. Both may be linked to a third factor such as hot weather Correct answer.
  2. Eating ice cream causes drowning
  3. The correlation proves the two events are unrelated
  4. Drowning rates cause ice cream sales to rise

Explanation

A correlation between two variables does not by itself establish causation; a third variable, such as warm weather that increases both swimming and ice cream purchases, can explain the pattern. Concluding direct causation or direct reversal from correlation alone is unjustified.

Question 26Scientific inquiry and investigation skills

A student wants to know whether a new type of battery lasts longer than a standard battery in a flashlight. Which observation would best support the claim that the new battery lasts longer?

  1. The new battery is sold in packages that contain more batteries than the standard brand.
  2. The new battery keeps the flashlight lit for 12 hours, while the standard battery keeps an identical flashlight lit for 8 hours. Correct answer.
  3. The new battery feels heavier in the hand than the standard battery.
  4. The new battery costs more money than the standard battery at the store.

Explanation

A claim about battery life is supported by measuring how long each battery actually powers a device under the same conditions. Only a direct comparison of operating time in identical flashlights provides evidence about duration. Price, package count, and weight are unrelated to how long the battery lasts.

Question 27Scientific inquiry and investigation skills

In a controlled experiment, which practice best helps reduce the influence of a variable that the experimenter did not plan to test?

  1. Repeating the experiment only when the first result is unclear
  2. Recording data only from the subjects that respond most strongly
  3. Changing several conditions at once so the effect averages out
  4. Randomly assigning subjects to treatment groups Correct answer.

Explanation

Random assignment distributes unknown or uncontrolled variables evenly across groups so their effects do not consistently favor one treatment. This protects the comparison from hidden biases. Changing several conditions at once confuses the cause, and selective recording or selective repetition distorts the evidence.

Question 28Scientific inquiry and investigation skills

A scientist repeats the same measurement of a chemical's melting point five times and obtains values that are all very close to one another but all about 3 degrees above the accepted value. How should these results be described?

  1. Accurate but not precise
  2. Neither accurate nor precise
  3. Both accurate and precise
  4. Precise but not accurate Correct answer.

Explanation

Precision refers to how closely repeated measurements agree with each other, while accuracy refers to how close they are to the true value. Here the cluster of similar readings shows high precision, but the consistent offset from the accepted value shows low accuracy.

Question 29Scientific inquiry and investigation skills

Which action is the best example of peer review in scientific practice?

  1. A laboratory technician files raw data in a secure cabinet.
  2. A researcher publishes findings on a personal website without any outside check.
  3. A teacher assigns students to summarize a news article about a study.
  4. A journal editor asks independent experts to evaluate a submitted manuscript before publication. Correct answer.

Explanation

Peer review is the evaluation of a scientific work by independent experts in the same field before it is accepted for publication. This scrutiny checks methods, reasoning, and interpretation. Personal posting, filing data, and classroom summarizing do not involve expert evaluation of the work.

Question 30Scientific inquiry and investigation skills

A student graphs the results of an experiment and finds that the data points form a clear curve rather than a straight line. What is the most appropriate interpretation?

  1. The measuring instrument must be broken.
  2. The independent variable had no effect on the dependent variable.
  3. The relationship between the variables is not linear. Correct answer.
  4. The experiment failed and the data should be discarded.

Explanation

The shape of a graph reveals the type of relationship between variables, and a curved pattern indicates a nonlinear relationship rather than a failure. Data can still be valid and informative when the trend is curved. Discarding data, blaming equipment, or concluding no effect is not justified by curvature alone.

Question 31Scientific inquiry and investigation skills

A researcher wants to determine whether a new drug lowers blood pressure. Which measurement should be the dependent variable?

  1. The dose of the drug given to each participant
  2. The number of participants in the study
  3. The blood pressure reading of each participant Correct answer.
  4. The length of time the study lasts

Explanation

The dependent variable is the outcome that is measured and is expected to change in response to the manipulated factor. Blood pressure is the outcome being tested, so it is the dependent variable. Dose, sample size, and study duration are design factors rather than measured outcomes.

Question 32Scientific inquiry and investigation skills

A student records the temperature of a liquid every minute and notices that the readings stop rising and remain constant for several minutes. What is the most reasonable conclusion?

  1. The liquid has reached a constant temperature, possibly during a phase change. Correct answer.
  2. The thermometer has stopped working correctly.
  3. The student must have misread every reading.
  4. The liquid is gaining heat faster than before.

Explanation

A plateau in a temperature-versus-time record often indicates a phase change, during which added energy changes the state rather than the temperature. The plateau is meaningful data, not evidence of error. Assuming instrument failure or misreading ignores a physically expected pattern.

Question 33Scientific inquiry and investigation skills

Which statement best describes a scientific model?

  1. A guess made without any supporting evidence
  2. A collection of raw measurements stored in a notebook
  3. A simplified representation used to explain and predict aspects of a real system Correct answer.
  4. A final and permanent description of nature that never changes

Explanation

A model is a simplified representation, often physical or mathematical, that helps scientists explain observations and make predictions. Models are useful precisely because they simplify complex systems. They are not permanent, not baseless guesses, and not merely raw data.

Question 34Scientific inquiry and investigation skills

A team of scientists investigates whether a certain lake is safe for swimming. Which approach best reflects sound scientific inquiry?

  1. Ask local residents whether they think the water is safe
  2. Collect water samples from many locations over several weeks and test them for contaminants Correct answer.
  3. Decide the lake is safe because it looks clear
  4. Test a single sample taken near the shore on one afternoon

Explanation

Sound inquiry relies on systematic sampling and objective testing rather than appearance or opinion. Multiple samples across locations and time give a more representative picture of water quality. A single sample or visual impression may miss contamination.

Question 35Scientific inquiry and investigation skills

A student wants to test whether the angle of a ramp affects how far a toy car rolls. Which variable should be kept constant?

  1. The mass of the toy car Correct answer.
  2. The starting height of the car
  3. The angle of the ramp
  4. The distance the car rolls

Explanation

In a controlled experiment only the independent variable is changed, so all other factors that could affect the outcome must be held constant. The car's mass is not being tested, so it must stay the same. Ramp angle is the independent variable, and rolling distance is the dependent variable.

Question 36Scientific inquiry and investigation skills

A scientist measures the density of a metal five times and gets 7.9, 7.8, 7.9, 8.0, and 7.9 g/cm³. Which statement about these data is most accurate?

  1. The measurements are unreliable because they are not identical.
  2. The measurements show high precision because they cluster closely together. Correct answer.
  3. The measurements show high accuracy because they match each other.
  4. The measurements cannot be analyzed because there are only five trials.

Explanation

Precision describes how closely repeated measurements agree, and these values differ by only a few tenths, showing a tight cluster. Accuracy would require comparing the average to an accepted value, which is not given. Small natural variation does not make data unreliable.

Question 37Scientific inquiry and investigation skills

Which statement best explains why scientists report their procedures in detail when publishing results?

  1. So that the results do not need to be checked
  2. So that other scientists can evaluate and attempt to reproduce the work Correct answer.
  3. So that the paper will be longer and appear more impressive
  4. So that competitors cannot understand the research

Explanation

Detailed procedures allow other researchers to evaluate the methods and to repeat the investigation, which is central to verifying scientific claims. Reproducibility depends on clear reporting of how the work was done. Length, secrecy, or avoiding checks are not scientific goals.

Question 38Scientific inquiry and investigation skills

A student claims that a certain plant food makes plants grow faster. To test this claim fairly, which setup is best?

  1. One plant given extra plant food and extra sunlight, and one given neither
  2. Two plants of different species, both given the plant food
  3. Two identical plants of the same species, one given the plant food and one given plain water, with all other conditions the same Correct answer.
  4. One plant measured only at the end of the experiment

Explanation

A fair test changes only the factor being investigated while holding everything else constant. Using identical plants with the same conditions except for the plant food isolates its effect. Different species, extra sunlight, or missing baseline data introduce confounding factors.

Question 39Scientific inquiry and investigation skills

A bar chart is used to display the number of students who chose each of four favorite colors. Why is a bar chart appropriate here?

  1. Because the data must always be shown as a pie chart
  2. Because the data are counts in separate categories Correct answer.
  3. Because the data are continuous measurements over time
  4. Because the data show a precise mathematical equation

Explanation

Bar charts are suited to categorical data, where each bar represents a distinct category and its height shows a count or frequency. Favorite colors form separate categories rather than a continuous scale. Continuous time data are better shown on a line graph.

Question 40Scientific inquiry and investigation skills

During an experiment, a student accidentally uses a balance that reads 0.5 g too high for every measurement. What type of error does this represent?

  1. Systematic error, because every reading is shifted in the same direction Correct answer.
  2. No error, because the readings are consistent
  3. Human error that cannot affect conclusions
  4. Random error, because each reading differs unpredictably

Explanation

A systematic error shifts all measurements by a consistent amount in the same direction, often due to faulty calibration. Random errors, by contrast, scatter unpredictably around a value. A constant offset can bias conclusions even though the readings are consistent.

Question 41Scientific inquiry and investigation skills

A hypothesis predicts that increasing light intensity will increase the rate of photosynthesis in pond weed. In an experiment, the rate increases at first but then levels off at high light intensities. What is the best interpretation?

  1. The experiment must have been done incorrectly.
  2. Light intensity has no effect on photosynthesis at any level.
  3. The hypothesis is completely wrong and should be abandoned.
  4. The prediction holds at lower intensities, but another factor limits the rate at high intensities. Correct answer.

Explanation

The initial increase supports the predicted relationship, while the plateau suggests a limiting factor such as carbon dioxide or temperature. Scientific interpretation should account for the full pattern rather than treating it as all-or-nothing. Discarding the hypothesis or blaming error ignores the partial support.

Question 42Scientific inquiry and investigation skills

Which of the following best describes the purpose of repeating an experiment multiple times?

  1. To eliminate the need for a control group
  2. To increase confidence that the results are consistent and not due to chance Correct answer.
  3. To make the data more complicated to analyze
  4. To guarantee that the hypothesis is true

Explanation

Replication helps determine whether results are consistent and reduces the chance that a finding is a fluke. It strengthens confidence but cannot prove a hypothesis absolutely true. Replication does not replace controls or add unnecessary complexity.

Question 43Scientific inquiry and investigation skills

A student measures the volume of water in a graduated cylinder and reads the bottom of the curved surface at eye level. Why is reading at eye level important?

  1. To avoid parallax error that would make the reading inaccurate Correct answer.
  2. To keep the cylinder from tipping over
  3. To make the water appear to have a larger volume
  4. To speed up the measurement process

Explanation

Reading a scale from an angle causes parallax, in which the apparent position of the meniscus shifts and produces an inaccurate value. Viewing at eye level aligns the observer with the scale. This practice improves accuracy rather than affecting volume, stability, or speed.

Question 44Scientific inquiry and investigation skills

A researcher finds that two variables change together in a dataset. Which statement about this finding is most scientifically sound?

  1. The correlation proves that both variables are unrelated.
  2. One variable definitely causes the other.
  3. The variables are correlated, but causation requires further controlled testing. Correct answer.
  4. The finding should be ignored because it is only a correlation.

Explanation

Correlation shows that variables change together but does not establish which one causes the other, since other factors may be responsible. Controlled experiments are needed to test causation. Ignoring a correlation discards potentially useful evidence.

Question 45Scientific inquiry and investigation skills

A class is designing an investigation to compare how quickly different materials conduct heat. Which measurement plan gives the most useful comparison?

  1. Ask students to touch each rod and rank the materials by feel
  2. Record the time for a fixed temperature change in identical rods of each material under the same conditions Correct answer.
  3. Record the final temperature of each rod after different lengths of time
  4. Use rods of different sizes for each material

Explanation

Comparing conduction requires a consistent measured outcome, such as the time needed for the same temperature change, with all other conditions held constant. Using identical rods and equal conditions isolates the material as the variable. Unequal times, unequal sizes, or subjective touch rankings introduce bias.

Question 46Scientific inquiry and investigation skills

Which statement correctly distinguishes a scientific law from a scientific theory?

  1. A law can never be changed, but a theory can.
  2. A theory is less supported by evidence than a law.
  3. A law is a guess, while a theory is a proven fact.
  4. A law describes a consistent relationship, while a theory explains why that relationship occurs. Correct answer.

Explanation

A scientific law typically states a consistent, observed relationship, often in mathematical form, while a theory is a well-supported explanation of underlying mechanisms. Both are grounded in evidence and can be revised. A theory is not a guess, and laws are not immune to revision.

Question 47Scientific inquiry and investigation skills

A student measures the boiling point of a liquid three times and gets 78.2 °C, 78.3 °C, and 78.1 °C. The accepted value is 78.3 °C. Which statement best characterizes these results?

  1. They are both precise and accurate. Correct answer.
  2. They are precise but inaccurate.
  3. They are accurate but imprecise.
  4. They are neither precise nor accurate.

Explanation

The three readings differ by only 0.2 °C, showing high precision, and their average of about 78.2 °C is very close to the accepted 78.3 °C, showing high accuracy. Both qualities are present. The small spread and near-match to the accepted value rule out the other descriptions.

Question 48Scientific inquiry and investigation skills

A scientist wants to know whether a soil additive increases the height of tomato plants. Which result would provide the strongest evidence?

  1. The additive is advertised as increasing plant height.
  2. Plants with the additive grow taller on average than control plants in several repeated trials. Correct answer.
  3. One plant with the additive grows taller than one plant without it.
  4. The scientist believes the additive works based on prior experience.

Explanation

Strong evidence comes from a controlled comparison repeated across multiple trials, which reduces the chance that a single result is due to chance. A single pair of plants or an advertisement provides weak or no experimental support. Prior belief alone is not evidence.

Question 49Scientific inquiry and investigation skills

Which action is most consistent with ethical conduct in scientific research?

  1. Claiming credit for a colleague's ideas
  2. Reporting all results, including those that do not support the hypothesis Correct answer.
  3. Changing the hypothesis after seeing the data without saying so
  4. Removing data points that make the results look inconsistent

Explanation

Ethical research requires honest and complete reporting, including results that fail to support the hypothesis, because selective reporting distorts the scientific record. Hiding inconvenient data, taking credit for others' work, or silently changing hypotheses are forms of misconduct.

Question 50Scientific inquiry and investigation skills

A student measures the mass of the same object on four different balances and records 12.4 g, 12.5 g, 12.4 g, and 12.5 g. The true mass is known to be 15.0 g. Which statement best describes these measurements?

  1. They are neither accurate nor precise
  2. They are precise but not accurate Correct answer.
  3. They are accurate but not precise
  4. They are both accurate and precise

Explanation

Precision describes how closely repeated measurements agree with one another, while accuracy describes how close a measurement is to the true value. The four readings cluster tightly together, so they are precise. However, every reading is about 2.5 g below the true mass, so the measurements are not accurate.