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HiSET Science study materials
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HiSET Science practice questions

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Question 1Science as Inquiry

A researcher observes that a certain plant wilts in the afternoon. She proposes that the wilting is caused by decreased water in the soil. This proposed explanation is best described as a:

  1. Hypothesis Correct answer.
  2. Conclusion
  3. Control group
  4. Scientific law

Explanation

A hypothesis is a proposed, testable explanation for an observation, and it must be possible to gather evidence that could support or refute it. Laws describe consistent patterns in nature rather than offering a tentative explanation.

Question 2Science as Inquiry

Which laboratory tool is most appropriate for measuring the volume of a liquid accurately?

  1. Graduated cylinder Correct answer.
  2. Thermometer
  3. Ruler
  4. Balance

Explanation

A graduated cylinder is marked with volume units and is designed to measure the volume of liquids. A balance measures mass, a thermometer measures temperature, and a ruler measures length.

Question 3Science as Inquiry

A student tests how the amount of fertilizer affects the height of tomato plants. The amount of fertilizer is the:

  1. Dependent variable
  2. Control group
  3. Constant
  4. Independent variable Correct answer.

Explanation

The independent variable is the factor the experimenter deliberately changes, which here is the amount of fertilizer. Plant height is the dependent variable because it is measured as a response.

Question 4Science as Inquiry

In an experiment, one group receives no treatment. This group is used to:

  1. Measure the independent variable
  2. Provide a baseline for comparison Correct answer.
  3. Test the dependent variable
  4. Increase the sample size

Explanation

A control group provides a baseline showing what happens without the treatment, so any difference in the experimental group can be attributed to the treatment. It is not designed to increase sample size or to measure variables directly.

Question 5Science as Inquiry

A scientist wants to compare the number of insects captured in four different habitats. Which type of graph is best for displaying these data?

  1. Bar graph Correct answer.
  2. Line graph
  3. Histogram
  4. Scatter plot

Explanation

A bar graph is used to compare counts or amounts across separate categories such as habitats. Line graphs show change over a continuous variable, scatter plots show relationships between two numeric variables, and histograms show the distribution of one continuous variable.

Question 6Science as Inquiry

A student writes, "The liquid in the beaker is blue." This statement is best classified as a(n):

  1. Hypothesis
  2. Prediction
  3. Inference
  4. Observation Correct answer.

Explanation

An observation is information gathered directly through the senses or with instruments, such as seeing that a liquid is blue. An inference is an interpretation or explanation based on observations.

Question 7Science as Inquiry

A student measures the mass of five identical marbles and records 4 g, 6 g, 8 g, 10 g, and 12 g. What is the mean mass?

  1. 8 g Correct answer.
  2. 10 g
  3. 7 g
  4. 6 g

Explanation

The mean is the sum of the values divided by the number of values. The sum is 40 g, and 40 g divided by 5 equals 8 g.

Question 8Science as Inquiry

Which metric unit is used to measure mass?

  1. Meter
  2. Gram Correct answer.
  3. Liter
  4. Second

Explanation

The gram is the base metric unit for mass. The liter measures volume, the meter measures length, and the second measures time.

Question 9Science as Inquiry

In an experiment testing how temperature affects the rate of a chemical reaction, which factor should be kept constant?

  1. The time the reaction takes
  2. The rate of the reaction
  3. The concentration of the reactants Correct answer.
  4. The temperature of the solution

Explanation

Controlled variables are factors held constant so they do not influence the outcome. The concentration of the reactants should stay the same while temperature is deliberately varied.

Question 10Science as Inquiry

A study finds that towns with more ice cream sales also have more drowning incidents. Which conclusion is best supported by this finding?

  1. The data are invalid because the variables are correlated.
  2. The two variables are correlated, but causation is not established. Correct answer.
  3. Eating ice cream causes drowning.
  4. Drowning causes ice cream sales to rise.

Explanation

A correlation shows that two variables change together, but it does not prove that one causes the other. A third factor, such as hot summer weather, could increase both ice cream sales and swimming activity.

Question 11Science as Inquiry

Two groups of students measure the boiling point of water. Group A takes 3 measurements, and Group B takes 30 measurements. Which statement is most accurate?

  1. Group A's average is more reliable because it is quicker.
  2. Group B's average is likely more reliable because of the larger sample size. Correct answer.
  3. Sample size has no effect on reliability.
  4. Both averages are equally reliable.

Explanation

A larger sample size tends to reduce the effect of random variation, making the average a more reliable estimate. Taking more measurements generally increases confidence in the result.

Question 12Science as Inquiry

In a clinical trial testing a new headache medication, one group receives a sugar pill with no active ingredient. This pill is called a:

  1. Bias
  2. Placebo Correct answer.
  3. Hypothesis
  4. Control variable

Explanation

A placebo is an inactive treatment given so that researchers can compare its effects with those of the real medication. Using a placebo helps separate the drug's effect from expectations or other factors.

Question 13Science as Inquiry

A data set contains the values 10, 12, 13, 14, and 51. Which statement best describes the effect of the value 51?

  1. It decreases the median.
  2. It makes the mode equal to 51.
  3. It increases the mean more than the median. Correct answer.
  4. It has no effect on the mean.

Explanation

The mean uses every value in the data set, so an extreme value such as 51 pulls it upward substantially. The median depends on the middle position of the ordered values and is much less affected by an outlier.

Question 14Science as Inquiry

A student's repeated measurements are close to one another but far from the true value. The measurements are:

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

Explanation

Precision refers to how close repeated measurements are to each other, while accuracy refers to how close they are to the true value. Measurements that cluster together but miss the true value are precise but not accurate.

Question 15Science as Inquiry

A line graph shows distance on the vertical axis and time on the horizontal axis. A straight line rising steadily indicates that the object is:

  1. Stationary
  2. Moving backward
  3. Moving at a constant speed Correct answer.
  4. Accelerating

Explanation

On a distance-versus-time graph, the slope represents speed. A straight line has a constant slope, so the object covers equal distances in equal time intervals.

Question 16Science as Inquiry

A student measures the density of a metal as 8.4 g/cm³. The accepted value is 8.0 g/cm³. What is the percent error of the student's measurement?

  1. 0.4%
  2. 5% Correct answer.
  3. 8.4%
  4. 4%

Explanation

Percent error is the absolute difference between the measured and accepted values, divided by the accepted value, then multiplied by 100. The difference is 0.4 g/cm³, and 0.4 divided by 8.0 equals 0.05, or 5%.

Question 17Science as Inquiry

In science, a well-tested explanation that is supported by a large body of evidence is called a:

  1. Scientific law
  2. Guess
  3. Scientific theory Correct answer.
  4. Hypothesis

Explanation

A scientific theory is a broad explanation that has been repeatedly tested and is supported by substantial evidence. A hypothesis is a tentative explanation, and a law describes a consistent pattern rather than explaining it.

Question 18Science as Inquiry

A researcher surveys visitors at a gym about exercise habits to represent the whole city. What is the main problem with this sample?

  1. The sample is biased toward people who exercise. Correct answer.
  2. The survey contains too many questions.
  3. The data are not numerical.
  4. The sample is too large.

Explanation

A sample must represent the larger population to support general conclusions. People at a gym are more likely to exercise than the city population as a whole, so the sample is biased.

Question 19Science as Inquiry

Why do scientists repeat experiments?

  1. To increase confidence in the results Correct answer.
  2. To change the hypothesis
  3. To eliminate the need for a control group
  4. To make the experiment take longer

Explanation

Repeating an experiment checks whether the results are consistent and reduces the chance that they came from random error or a one-time mistake. Consistent results across repetitions increase confidence in the findings.

Question 20Science as Inquiry

A table shows that as the amount of sunlight increases, plant growth increases and then levels off. Which conclusion is best supported by these data?

  1. Sunlight has no effect on plant growth.
  2. Plants grow best in complete darkness.
  3. Plant growth increases with sunlight up to a point, then stops increasing. Correct answer.
  4. More sunlight always produces more growth without limit.

Explanation

The data show growth rising as sunlight increases and then flattening out, which means the benefit of extra sunlight is limited. The conclusion should describe this pattern rather than claim no effect or unlimited growth.

Question 21Science as Inquiry

A student wants to test whether a new fertilizer increases crop yield. He applies fertilizer to a field in full sun and no fertilizer to a field in shade. What is the main flaw in this design?

  1. He did not form a hypothesis.
  2. Two variables differ between the fields, so the cause of any difference cannot be determined. Correct answer.
  3. He used too much fertilizer.
  4. He did not measure crop yield.

Explanation

An experiment should change only one variable at a time so the cause of any difference can be identified. Here sunlight and fertilizer both differ, making it impossible to tell which one affected the yield.

Question 22Science as Inquiry

A graduated cylinder is marked in 1 mL increments. A student records a volume of 24.5 mL. Which statement about this measurement is most accurate?

  1. The measurement is invalid because graduated cylinders measure mass.
  2. The measurement is too precise because the cylinder cannot be read to 0.5 mL.
  3. The measurement should be rounded to 25 mL because the markings are 1 mL.
  4. The measurement has an estimated digit between markings and is reasonable. Correct answer.

Explanation

When reading a scale, scientists typically estimate one digit beyond the smallest marked increment. With 1 mL markings, estimating to 0.1 mL or 0.5 mL is reasonable, so 24.5 mL is an appropriate reading.

Question 23Science as Inquiry

A scientist claims that a new drug lowers blood pressure. The treatment group's average pressure drops by 2 mm Hg, while the control group's average drops by 1.5 mm Hg, with large variability in both groups. What is the best evaluation of the claim?

  1. The difference is small compared with the variability, so more data are needed. Correct answer.
  2. The drug is clearly effective.
  3. The drug caused a large decrease.
  4. The control group should be eliminated.

Explanation

A meaningful effect should be larger than the random variation in the data. Here the 0.5 mm Hg difference is small relative to the large variability, so the evidence is weak and further study is needed.

Question 24Science as Inquiry

A liquid has a density of 2 g/cm³. What is the mass of 5 cm³ of this liquid?

  1. 2.5 g
  2. 0.4 g
  3. 10 g Correct answer.
  4. 20 g

Explanation

Density equals mass divided by volume, so mass equals density multiplied by volume. Multiplying 2 g/cm³ by 5 cm³ gives 10 g.

Question 25Science as Inquiry

Which of these is a testable scientific question?

  1. How does the amount of water affect the growth rate of bean plants? Correct answer.
  2. Is chocolate the best flavor?
  3. Should students be required to study science?
  4. Why is the sky prettier in summer?

Explanation

A testable scientific question involves variables that can be measured and evidence that can be collected. Asking how water amount affects growth rate identifies a cause-and-effect relationship that can be investigated.

Question 26Science as Inquiry

The metric prefix milli- represents which factor?

  1. one-thousandth (0.001) Correct answer.
  2. one million (1,000,000)
  3. one thousand (1,000)
  4. one-hundredth (0.01)

Explanation

The prefix milli- means one-thousandth, or 10^-3, so 1 milliliter is 0.001 liter. Other metric prefixes represent different powers of ten.

Question 27Science as Inquiry

A student needs to heat a liquid in a test tube over a burner. Which practice is safest?

  1. Aim the test tube opening away from people and move it gently through the flame Correct answer.
  2. Point the test tube opening toward a classmate
  3. Fill the test tube to the top before heating
  4. Seal the test tube with a stopper before heating

Explanation

Heating a test tube can make trapped gas or liquid escape suddenly, so the opening should face away from people. Test tubes should be no more than about one-third full and should never be sealed while heated.

Question 28Science as Inquiry

In scientific inquiry, a hypothesis is best described as:

  1. a final conclusion that cannot be changed
  2. a testable proposed explanation for an observation Correct answer.
  3. a random guess made without information
  4. a summary of data already collected

Explanation

A hypothesis is a testable proposed explanation or prediction based on prior knowledge and observations. It must be phrased so that evidence can support or reject it.

Question 29Science as Inquiry

A student notices that a metal spoon left in hot soup becomes warm. Which statement is an inference rather than an observation?

  1. The soup is hot.
  2. The spoon feels warm to the touch.
  3. Heat moved from the soup into the spoon. Correct answer.
  4. The spoon is made of metal.

Explanation

An observation is information gathered directly through the senses or instruments, while an inference is a logical interpretation of those observations. The movement of heat is inferred from the spoon becoming warm.

Question 30Science as Inquiry

A statement that describes a consistent pattern in nature, often expressed as a mathematical relationship, is called a:

  1. control group
  2. scientific law Correct answer.
  3. sample
  4. hypothesis

Explanation

A scientific law summarizes a consistent natural pattern, often as an equation or rule, without necessarily explaining why it happens. A hypothesis is a testable proposed explanation, not a summary law.

Question 31Science as Inquiry

Why do scientists use models such as diagrams or computer simulations?

  1. Models are always exact copies of real objects.
  2. Models help scientists visualize and test ideas that are difficult to observe directly. Correct answer.
  3. Models replace the need for collecting evidence.
  4. Models prove a hypothesis is true before experiments are done.

Explanation

Models simplify or represent complex systems so scientists can visualize, analyze, and make predictions about things that may be too large, small, or dangerous to study directly. Models are tools and must be checked against evidence.

Question 32Science as Inquiry

A student wants to compare the number of students who chose each of four favorite sports. Which graph is most appropriate?

  1. line graph
  2. bar graph Correct answer.
  3. histogram
  4. scatterplot

Explanation

Favorite sports are categorical data, and a bar graph clearly compares counts or amounts among categories. Line graphs and scatterplots are generally used for continuous numerical relationships.

Question 33Science as Inquiry

In an experiment, the independent variable is the factor that is:

  1. kept the same for all groups
  2. changed or manipulated by the researcher Correct answer.
  3. measured as a result of the experiment
  4. used to calculate the average

Explanation

The independent variable is the one the researcher deliberately changes or selects to observe its effect. The dependent variable is what is measured in response.

Question 34Science as Inquiry

A student tests how the amount of water affects the height of bean plants. What is the dependent variable?

  1. type of soil
  2. amount of water
  3. amount of sunlight
  4. height of the bean plants Correct answer.

Explanation

The dependent variable is the outcome measured in the experiment; here it is plant height. The amount of water is the independent variable being changed.

Question 35Science as Inquiry

A student tests whether different colors of light affect the growth of algae. Which factor should be kept the same in all trials?

  1. number of trials
  2. temperature of the water Correct answer.
  3. color of light
  4. growth of algae

Explanation

To isolate the effect of light color, all other conditions that could affect algae growth should be held constant, including water temperature. The color of light is the independent variable and algae growth is the dependent variable.

Question 36Science as Inquiry

A data set contains the values 3, 7, 7, 9, 12, 15. What is the median?

  1. 8 Correct answer.
  2. 7
  3. 7.5
  4. 9

Explanation

For an even number of ordered values, the median is the mean of the two middle values. The middle values are 7 and 9, and their average is 8.

Question 37Science as Inquiry

For the data set 14, 18, 21, 25, 31, what is the range?

  1. 31
  2. 17 Correct answer.
  3. 21
  4. 14

Explanation

The range is the difference between the highest and lowest values. Here, 31 - 14 = 17.

Question 38Science as Inquiry

How many liters are in 2,500 milliliters?

  1. 2.5 L Correct answer.
  2. 250 L
  3. 25 L
  4. 0.25 L

Explanation

There are 1,000 milliliters in 1 liter, so divide the number of milliliters by 1,000. 2,500 mL ÷ 1,000 = 2.5 L.

Question 39Science as Inquiry

How many significant figures are in the measurement 0.00420 g?

  1. 6
  2. 4
  3. 2
  4. 3 Correct answer.

Explanation

Leading zeros before the first nonzero digit are not significant. The digits 4, 2, and the trailing zero after the decimal are significant, giving three significant figures.

Question 40Science as Inquiry

A thermometer consistently reads 2 °C higher than the true temperature for every measurement. This is an example of:

  1. systematic error Correct answer.
  2. a control group
  3. sampling bias
  4. random error

Explanation

A systematic error is a consistent offset in the same direction, often caused by a miscalibrated instrument. Random error would vary unpredictably from measurement to measurement.

Question 41Science as Inquiry

In an experiment testing a new fertilizer, why are plants randomly assigned to treatment and control groups?

  1. to reduce the chance that groups differ in important ways before treatment Correct answer.
  2. to guarantee the fertilizer works
  3. to eliminate the need for a control group
  4. to increase the number of variables

Explanation

Random assignment helps make treatment and control groups similar in both known and unknown factors, so differences in outcome are more likely due to the treatment. It does not guarantee a particular result.

Question 42Science as Inquiry

What is the main purpose of peer review before a scientific paper is published?

  1. to have experts check the study's methods, evidence, and reasoning Correct answer.
  2. to make sure the results agree with popular opinion
  3. to prove the hypothesis is correct
  4. to allow the author to avoid revising the paper

Explanation

Peer review asks independent experts to evaluate whether the methods, evidence, and conclusions are sound before publication. It improves quality but does not prove a hypothesis correct.

Question 43Science as Inquiry

A graph shows a steady increase in plant height from week 1 to week 4. A student predicts the height at week 6 by continuing the trend. This prediction is an example of:

  1. extrapolation Correct answer.
  2. a controlled experiment
  3. interpolation
  4. random sampling

Explanation

Extrapolation is estimating a value outside the range of observed data by extending a trend. Interpolation would estimate a value between known data points.

Question 44Science as Inquiry

Which graph is best for showing how temperature changes continuously over 24 hours?

  1. pie chart
  2. bar graph
  3. Venn diagram
  4. line graph Correct answer.

Explanation

A line graph shows how a continuous variable changes over time by connecting data points. Bar graphs compare categories, pie charts show parts of a whole, and Venn diagrams compare sets.

Question 45Science as Inquiry

A table shows that a plant given 0 hours of light grows 1 cm, 2 hours grows 2 cm, 4 hours grows 4 cm, and 8 hours grows 6 cm. Which conclusion is best supported?

  1. Growth increases with light but then levels off. Correct answer.
  2. Light has no effect on growth.
  3. Darkness produces the tallest plants.
  4. Growth rate stays constant as light increases.

Explanation

Growth rises from 1 cm to 6 cm as light increases, but the gain from 4 to 8 hours is smaller than earlier gains. The data support increasing growth with diminishing returns.

Question 46Science as Inquiry

A researcher finds that students who eat breakfast score higher on a test. Some breakfast eaters also studied more. Why can the researcher not conclude that breakfast causes higher scores?

  1. Studying time is a confounding variable that could affect scores. Correct answer.
  2. The sample size was too large.
  3. Test scores cannot be measured numerically.
  4. Breakfast eaters were randomly assigned.

Explanation

A confounding variable is related to both the proposed cause and the outcome, making the cause-and-effect conclusion uncertain. Since studying more could also raise scores, the effect of breakfast is mixed with studying.

Question 47Science as Inquiry

A website posts an online poll asking visitors whether they support a new park. Which statement best explains why the results may be biased?

  1. The poll uses too many answer choices.
  2. The poll measures opinions instead of facts.
  3. Only people who visit the website and choose to respond are included. Correct answer.
  4. The poll was conducted over the internet rather than by mail.

Explanation

A voluntary online poll samples only people who visit that website and decide to respond, which may not represent the larger population. This self-selection can bias the results.

Question 48Science as Inquiry

A study reports that a new vitamin improves memory in 5 volunteers, with an average improvement of 1 point on a 100-point test. What is the best evaluation of the claim?

  1. The small sample and tiny improvement make the result weak evidence. Correct answer.
  2. The claim is strong because the test was out of 100 points.
  3. The claim is invalid because averages cannot be used.
  4. The claim is proven because improvement was observed.

Explanation

Evidence is judged by sample size, effect size, and study design, among other factors. A 1-point average change in only 5 volunteers is weak evidence and could easily occur by chance.

Question 49Science as Inquiry

A student measures a plant's height as 2 cm at day 1 and 10 cm at day 5. What is the average growth rate over this period?

  1. 0.5 cm per day
  2. 2 cm per day Correct answer.
  3. 1 cm per day
  4. 8 cm per day

Explanation

Average rate is the change in height divided by the change in time. The plant grew 8 cm over 4 days, so 8 ÷ 4 = 2 cm per day.

Question 50Science as Inquiry

A student wants to test how temperature affects enzyme activity. Which design best controls other variables?

  1. Use the same enzyme amount and pH, changing only temperature. Correct answer.
  2. Change temperature and pH together for each trial.
  3. Test only one temperature and repeat it many times.
  4. Use different enzyme amounts for each temperature.

Explanation

To test temperature, all other factors that affect enzyme activity, such as enzyme amount and pH, must be held constant. Changing them along with temperature would confound the results.