I85PREP
⌘ K
PSSA Grade 8 Science study materials
PSSA Grade 8 Science study resources

PSSA Grade 8 Science practice questions

One question at a time. Build your PSSA Grade 8 Science understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1The Nature of Science

Which statement best describes a scientific hypothesis?

  1. A testable prediction based on prior knowledge Correct answer.
  2. A final conclusion that has been proven true
  3. A broad explanation supported by much evidence
  4. A summary of data collected during an experiment

Explanation

A hypothesis is a proposed, testable explanation or prediction formed before the main investigation, based on observations and prior knowledge. It must be worded so that evidence could support or reject it.

Question 2The Nature of Science

A student sees that a puddle on the sidewalk is smaller than it was in the morning and says the water evaporated. Which statement is an inference?

  1. The sidewalk is wet around the puddle.
  2. The puddle was larger at 8 a.m.
  3. The water evaporated into the air. Correct answer.
  4. The puddle is smaller than it was this morning.

Explanation

Observations are gathered directly through the senses or with instruments, while inferences are explanations or interpretations built from those observations. Saying the water evaporated explains why the puddle shrank and is not something the student directly saw.

Question 3The Nature of Science

Which observation is a quantitative observation?

  1. The leaf is 6 centimeters long. Correct answer.
  2. The powder is white and shiny.
  3. The rock feels rough and gritty.
  4. The liquid smells like vinegar.

Explanation

Quantitative observations involve numbers and measurements, while qualitative observations describe qualities such as color, texture, or odor. A length given in centimeters is a measurement, so it is quantitative.

Question 4The Nature of Science

A student tests how the amount of sunlight affects the growth of bean plants. Which factor is the independent variable?

  1. The number of leaves per plant
  2. The final height of the plants
  3. The daily sunlight exposure Correct answer.
  4. The type of soil in the pots

Explanation

The independent variable is the factor the experimenter deliberately changes, and the dependent variable is what is measured in response. Sunlight is the factor the student chooses to vary, so it is the independent variable.

Question 5The Nature of Science

In an experiment on how fertilizer affects tomato plant height, which is the dependent variable?

  1. Height of the tomato plants Correct answer.
  2. Number of plants in each group
  3. Amount of water each plant receives
  4. Amount of fertilizer added

Explanation

The dependent variable is the outcome measured to see whether the independent variable had an effect. Plant height is what is measured, so it responds to the fertilizer amounts that were changed.

Question 6The Nature of Science

A scientist tests a new fertilizer by giving it to 10 plants and giving no fertilizer to 10 other plants. Why is the group with no fertilizer included?

  1. To test two fertilizers at once
  2. To make the experiment finish faster
  3. To grow more plants in the experiment
  4. To provide a standard for comparison Correct answer.

Explanation

A control group receives no treatment so the results of the treated group can be compared against a baseline. Without that comparison, the scientist could not tell whether the fertilizer caused any change.

Question 7The Nature of Science

In an experiment on how temperature affects seed germination, all seeds must be the same type and receive the same amount of water. These unchanged factors are called:

  1. experimental errors
  2. independent variables
  3. dependent variables
  4. controlled variables Correct answer.

Explanation

Controlled variables are the factors deliberately kept constant so they cannot influence the outcome. Keeping seed type and water the same ensures any difference in germination can be credited to temperature.

Question 8The Nature of Science

Which metric unit would a student use to measure the mass of a small rock?

  1. newton
  2. liter
  3. degree Celsius
  4. gram Correct answer.

Explanation

Mass in the metric system is measured in grams and kilograms. Liters measure volume, newtons measure force, and degrees Celsius measure temperature.

Question 9The Nature of Science

Where should a student look to correctly read the volume of water in a graduated cylinder?

  1. At the bottom of the meniscus at eye level Correct answer.
  2. At the top of the meniscus from above
  3. At the water line on the outside of the glass
  4. At the tallest mark on the cylinder

Explanation

Water curves upward at the edges of a cylinder, forming a meniscus, and the correct volume is read at the lowest point of that curve. The eye must be level with the meniscus to avoid a parallax error.

Question 10The Nature of Science

A balance gives the readings 5.42 g, 5.41 g, and 5.43 g for a sample whose true mass is 5.00 g. How should these readings be described?

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

Explanation

Precision describes how closely repeated measurements agree with each other, while accuracy describes how close they are to the true value. These readings cluster tightly together but all sit well above 5.00 g, so they are precise but not accurate.

Question 11The Nature of Science

Which statement correctly describes the relationship between a scientific theory and a scientific law?

  1. A law explains observations, and a theory only describes a repeating pattern.
  2. Laws are permanently replaced by theories whenever new evidence is gathered.
  3. Theories are educated guesses that always become laws once they are proven correct.
  4. A theory explains observations; a law describes a pattern. Correct answer.

Explanation

A scientific law states a consistent, describable pattern in nature, while a theory is a well-tested explanation for why that pattern occurs. Neither one is a guess, and neither automatically turns into the other.

Question 12The Nature of Science

Why do scientists use models such as a diagram of an atom?

  1. Models show every detail of the real object.
  2. Models are exact copies of the objects studied.
  3. Models prove a hypothesis without any data.
  4. Models show things too small to observe directly. Correct answer.

Explanation

Models are simplified representations used to study objects or processes that are too small, too large, or too complex to examine directly. Because they are simplified, a model always leaves out some details of the real thing.

Question 13The Nature of Science

Before publishing results, scientists send their work to other experts to be reviewed. What is the main purpose of this step?

  1. To give credit to scientists who did not take part
  2. To decide whether the results will be popular
  3. To check whether the methods and conclusions are sound Correct answer.
  4. To make sure the paper is written in an interesting style

Explanation

Peer review asks independent experts to examine the design, data, and reasoning of a study before it is published. This screening helps catch errors and unsupported claims so that weak work is less likely to enter the scientific record.

Question 14The Nature of Science

A student measures the boiling point of a liquid three times instead of once. What is the main reason for repeating the measurement?

  1. To prove the hypothesis is already correct
  2. To make the experiment take longer
  3. To reduce the effect of random errors Correct answer.
  4. To change the independent variable

Explanation

Repeated trials help average out small random variations such as timing slips or slight misreadings. Averaging several trials gives a result that is more reliable than a single measurement.

Question 15The Nature of Science

Two students test how light affects plant growth. Student A uses 2 plants per group, while Student B uses 30 plants per group and keeps everything else the same. Why are Student B's results more dependable?

  1. B's plants grew taller than the plants in A's groups.
  2. B gave the plants a greater amount of light.
  3. B's larger groups average out odd individual plants. Correct answer.
  4. B changed more variables at the same time than A did.

Explanation

A larger sample size makes results less sensitive to unusual individuals, so the average better reflects the typical response. With only two plants per group, one unusually healthy or unhealthy plant can strongly shift the outcome.

Question 16The Nature of Science

A company that sells a study app pays for a study showing the app raises test scores. What is the best reason to be cautious about these results?

  1. The study used a very large number of students.
  2. The researchers may profit from the results. Correct answer.
  3. The study did not include any actual test scores.
  4. The study was published in a scientific journal.

Explanation

A conflict of interest exists when the people running or funding a study stand to gain from a particular result, which can bias how data are collected or reported. Independent replication is needed before such findings are trusted.

Question 17The Nature of Science

A student records a plant's height each week: week 1, 3 cm; week 2, 6 cm; week 3, 9 cm; week 4, 12 cm. Which statement describes the pattern in these data?

  1. The plant grew 3 cm each week. Correct answer.
  2. The plant's growth slowed each week.
  3. The plant grew 6 cm each week.
  4. The plant grew 2 cm each week.

Explanation

Subtracting each week's height from the next gives a constant increase of 3 cm, which is a steady linear pattern. A constant gain per week means growth did not speed up or slow down.

Question 18The Nature of Science

Group A's paper planes use wide wings and average 12 m per flight. Group B's planes use narrow wings and average 8 m per flight. All other features are identical. Which conclusion is best supported by these results?

  1. Wide wings make the planes heavier than narrow wings do.
  2. Narrow wings are better for all paper planes.
  3. Wide-wing planes flew farther in this test. Correct answer.
  4. Wing width has no effect on flight distance.

Explanation

A conclusion must stay within what the data show, so it should describe the measured difference between the two wing designs without overgeneralizing. Since only wing width varied, the 4 m difference supports the narrower claim that wide wings flew farther here.

Question 19The Nature of Science

Which tool should a student use to find the temperature of a liquid?

  1. a metric ruler
  2. a graduated cylinder
  3. a triple-beam balance
  4. a thermometer Correct answer.

Explanation

Each measuring tool is designed for a specific quantity, and temperature is measured with a thermometer. Choosing the wrong instrument would give a number that does not describe heat energy.

Question 20The Nature of Science

Before heating a liquid in a laboratory, a student should:

  1. wear safety goggles Correct answer.
  2. point the test tube toward a partner
  3. fill the container to the top
  4. taste the liquid to identify it

Explanation

Safety goggles protect the eyes from splashes, fumes, and broken glass whenever chemicals are heated or handled. Standard lab rules also require never tasting materials and always aiming containers away from people.

Question 21The Nature of Science

Which statement is a prediction rather than an observation?

  1. The ice will melt faster in warm water. Correct answer.
  2. The cup has a small crack near the top edge.
  3. The water in the cup is clear.
  4. The ice cube feels cold.

Explanation

An observation describes what is noticed now, while a prediction states what is expected to happen next based on prior knowledge. Saying the ice will melt faster in warm water describes a future result that has not yet been seen.

Question 22The Nature of Science

Which statement best describes the process of scientific inquiry?

  1. It ends as soon as one experiment gives a result.
  2. It always starts with a well-known theory to prove.
  3. It may repeat or revise steps as evidence changes. Correct answer.
  4. It follows one fixed order of steps that never changes.

Explanation

Scientific inquiry is flexible rather than a rigid checklist, so investigators often go back to revise questions, methods, or explanations when new evidence appears. Conclusions are always open to further testing.

Question 23The Nature of Science

Several independent research teams repeat another team's experiment and obtain the same results. What do these findings most strongly support?

  1. The original team's data should now be discarded.
  2. The hypothesis is now a proven fact that cannot change.
  3. The original experiment contained no errors of any kind.
  4. The findings are likely to be valid and dependable. Correct answer.

Explanation

When independent teams using their own equipment and procedures reach the same result, the chance that the finding came from one team's mistake drops. This replication increases confidence in the results without making them permanent or error-free.

Question 24The Nature of Science

Which example best shows how scientific knowledge can lead to new technology?

  1. Knowledge of cell structure led to new medicines. Correct answer.
  2. A scientist classifies a newly discovered insect.
  3. A museum displays a model of a dinosaur skeleton.
  4. A student writes a report about the life cycle of a frog.

Explanation

Technology is the application of scientific understanding to design useful products or processes. Using knowledge of cells to develop medicines turns an explanation of nature into a practical tool.

Question 25The Nature of Science

A student wants to show how a plant's height changed continuously over 10 weeks. Which way of displaying the data is most appropriate?

  1. a circle graph
  2. a bar graph
  3. a data table
  4. a line graph Correct answer.

Explanation

A line graph plots a variable measured continuously over time and makes trends easy to see. Circle graphs show parts of a whole, and bar graphs compare separate categories rather than a continuous change.

Question 26The Nature of Science

A student dissolves different amounts of sugar in equal volumes of water and records the boiling point of each solution. What is the independent variable in this investigation?

  1. the amount of sugar dissolved Correct answer.
  2. the boiling point of each solution
  3. the type of container used
  4. the volume of water used

Explanation

The independent variable is the factor the experimenter deliberately changes from trial to trial. Here the sugar amount is changed on purpose, while the boiling point is what is measured in response and the water volume and container are kept the same.

Question 27The Nature of Science

In science, which term describes a possible explanation for an observation that can be tested by an experiment?

  1. a variable
  2. a law
  3. a conclusion
  4. a hypothesis Correct answer.

Explanation

A hypothesis is a testable proposed explanation made before the main investigation. It is supported or rejected by the evidence the experiment produces.

Question 28The Nature of Science

Which metric unit is most appropriate for recording the length of a classroom desk?

  1. degrees Celsius
  2. milliliters
  3. meters Correct answer.
  4. grams

Explanation

Length is measured in metric units based on the meter, and a desk is a convenient size to record in meters. Milliliters, grams, and degrees Celsius measure other quantities.

Question 29The Nature of Science

A student records that a liquid is clear and has no odor. These notes are best described as which kind of observation?

  1. a prediction
  2. a qualitative observation Correct answer.
  3. a measurement
  4. an inference

Explanation

Qualitative observations describe qualities such as color, texture, or smell without using numbers. Quantitative observations, by contrast, involve measurements and counts.

Question 30The Nature of Science

What is the safest way for a student to detect the odor of a chemical in the laboratory?

  1. Waft the vapor toward the nose with a hand Correct answer.
  2. Pour a sample of the chemical onto the bench top
  3. Place the nose directly over the container and sniff
  4. Heat the chemical until the odor is strong

Explanation

Wafting brings a small amount of vapor to the nose and limits exposure to fumes. Chemicals should never be smelled directly, heated to release fumes, or spilled on purpose.

Question 31The Nature of Science

When a student graphs the results of an experiment, the variable that was deliberately changed should be placed where?

  1. on the y-axis, labeled with units
  2. nowhere, because only the outcome is graphed
  3. on the x-axis, labeled with units Correct answer.
  4. in the title of the graph

Explanation

The independent variable is plotted on the horizontal x-axis, and the dependent variable is plotted on the vertical y-axis. Both axes should carry labels and units.

Question 32The Nature of Science

Which instrument would a student use to measure the force needed to pull a wooden block across a table?

  1. a thermometer
  2. a spring scale Correct answer.
  3. a metric ruler
  4. a graduated cylinder

Explanation

A spring scale measures force, usually reported in newtons, by how far the spring stretches under a pull. The other instruments measure volume, length, and temperature.

Question 33The Nature of Science

Which statement is an opinion rather than a claim that can be supported by scientific evidence?

  1. The plant in the window grew 4 cm during one week.
  2. Water boils at 100 degrees Celsius at sea level.
  3. This rock sample contains three different minerals.
  4. The science museum is the most interesting place. Correct answer.

Explanation

A scientific claim can be checked against observations or measurements that others can repeat. Statements about personal preferences, such as which place is most interesting, cannot be tested this way.

Question 34The Nature of Science

A student tests how the type of soil affects how fast water drains through it. The student uses the same amount of water, the same container, and the same volume of soil in every trial. What is the role of these repeated conditions?

  1. They are controlled variables held constant in every trial Correct answer.
  2. They are the dependent variable that is being measured
  3. They are the conclusions drawn from the results
  4. They are the independent variable that the student is testing

Explanation

Controlled variables are factors kept identical across trials so they cannot explain differences in the outcome. Only the soil type should vary, and drainage time is what gets measured.

Question 35The Nature of Science

A class measures how quickly sugar dissolves in water at four different temperatures. What is the dependent variable?

  1. the amount of sugar in each cup
  2. the type of cup used
  3. the four temperatures used
  4. the time it takes the sugar to dissolve Correct answer.

Explanation

The dependent variable is the response that is measured, which here is the dissolving time. Temperature is the independent variable, and the sugar amount and cup type are held constant.

Question 36The Nature of Science

A student has a small, irregularly shaped stone and needs its volume. Which method is most appropriate?

  1. Place the stone on a balance and read its mass in grams
  2. Heat the stone and record how much its temperature changes
  3. Submerge the stone in water and measure the rise in the water level Correct answer.
  4. Measure its edges with a ruler and multiply length by width by height

Explanation

Water displacement works for irregular objects because the volume of water pushed aside equals the volume of the object. The length-times-width-times-height formula applies only to rectangular solids.

Question 37The Nature of Science

A student surveyed classmates about their favorite of four sports. Which display best compares the numbers choosing each sport?

  1. a table of temperatures
  2. a diagram of a sports field
  3. a bar graph with one bar for each sport Correct answer.
  4. a line graph of the survey responses

Explanation

A bar graph is used to compare counts among separate categories, because the height of each bar shows the number in that category. Line graphs are reserved for showing change in a continuous measurement over time.

Question 38The Nature of Science

Why do scientists publish their procedures and results in journals that other scientists can read?

  1. so others can evaluate, repeat, and build on the work Correct answer.
  2. so the data can be kept secret from competitors
  3. so the results can never be questioned again
  4. so the scientists can avoid repeating any trials

Explanation

Publication lets the scientific community check methods, repeat the investigation, and extend the findings. It is a form of open communication, not a way to end questioning or hide information.

Question 39The Nature of Science

A researcher wants to estimate the average height of trees in a large forest. Which plan gives the most representative sample?

  1. Measure the ten tallest trees near the parking lot
  2. Measure the trees the researcher thinks look healthiest
  3. Measure only the trees that are easy to reach from the road
  4. Measure trees chosen at random from many parts of the forest Correct answer.

Explanation

A random sample drawn from across the whole area is most likely to reflect the true variety in the forest. Choosing trees by size, access, or appearance introduces bias.

Question 40The Nature of Science

A student's measurements do not support the hypothesis that was tested. What is the most scientific response?

  1. Change the measurements so they fit the hypothesis
  2. Repeat the experiment until the data agree
  3. Report the results honestly and revise the hypothesis Correct answer.
  4. Ignore the data and keep the hypothesis as it is

Explanation

In science the evidence takes priority, so results are reported as recorded and the explanation is adjusted to fit them. Altering or discarding data would make the findings unreliable.

Question 41The Nature of Science

Which of these would most likely lead scientists to revise an accepted scientific explanation?

  1. a vote taken at a science meeting
  2. a scientist who disagrees but has no data
  3. a popular book that repeats the explanation
  4. new evidence that the explanation cannot account for Correct answer.

Explanation

Scientific explanations are revised when repeated observations or new data conflict with them. Authority, popularity, or unsupported disagreement is not sufficient to change an explanation.

Question 42The Nature of Science

A student wants to know whether light color affects plant growth but gives one group blue light with extra water and the other group white light with less water. What is the main problem with this design?

  1. The experiment used too many trials
  2. Two variables change at once, so the cause cannot be identified Correct answer.
  3. No light was given to either group
  4. The plants were not measured at all

Explanation

A valid experiment changes only one independent variable so that any difference in the outcome can be traced to it. Because light color and water amount both differ, the results cannot show which one caused the change.

Question 43The Nature of Science

Why can a model of a cell never show everything about a real cell?

  1. Models are always built from living materials
  2. Models are only used when experiments are impossible
  3. A model is a simplified version that leaves out some details Correct answer.
  4. Models cannot be drawn to scale

Explanation

Models are representations that highlight key features while simplifying or omitting others so they are easier to study. Their usefulness comes with limits, because the real system is more complex.

Question 44The Nature of Science

A chemical splashes into a student's eye during a lab. What should the student do first?

  1. Use the eyewash station and tell the teacher Correct answer.
  2. Rub the eye with a paper towel
  3. Put on safety goggles over the eye
  4. Wait until the end of class to report it

Explanation

Immediate flushing at the eyewash station dilutes and removes the chemical, and the teacher must be told so proper follow-up can occur. Delaying or rubbing the eye can worsen the injury.

Question 45The Nature of Science

A hallway is 12.5 meters long. How many centimeters is that?

  1. 0.125 cm
  2. 125 cm
  3. 1,250 cm Correct answer.
  4. 1.25 cm

Explanation

One meter equals 100 centimeters, so multiplying 12.5 by 100 gives 1,250 centimeters. Moving from a larger metric unit to a smaller one increases the number.

Question 46The Nature of Science

Which question could be answered by a scientific investigation?

  1. Does the amount of water affect how tall a bean plant grows? Correct answer.
  2. Should students be required to study science in every grade of school?
  3. Which of the local musicians is the most talented?
  4. Is the color blue more beautiful than the color green?

Explanation

A question is scientific when it can be answered by collecting measurable evidence, such as comparing plant heights at different watering levels. Questions about beauty, policy, or talent rest on personal or social judgments that data cannot settle.

Question 47The Nature of Science

A balance reads 0.4 g too high every time it is used because it was not zeroed before weighing. Which statement best describes the effect on the measurements?

  1. The readings are accurate because the error is small
  2. The readings are valid because the same balance was used each time
  3. The readings are consistently off, which is a systematic error Correct answer.
  4. The readings are imprecise because each one differs by a random amount

Explanation

A systematic error shifts every reading in the same direction by a similar amount, usually because of a faulty or misadjusted instrument. Precision may remain high, but accuracy is reduced until the instrument is corrected.

Question 48The Nature of Science

Ice cream sales and swimming pool visits both rise in July. Which conclusion is best supported?

  1. Swimming causes people to buy ice cream
  2. There is no relationship between the two measurements
  3. Eating ice cream causes people to swim
  4. Both may be influenced by a third factor, such as warmer weather Correct answer.

Explanation

Two quantities that rise and fall together are correlated, but correlation alone does not show that one causes the other. A third factor such as warm summer weather can drive both patterns.

Question 49The Nature of Science

Three groups of identical seedlings receive 2, 4, and 6 hours of light per day. After two weeks their average heights are 5 cm, 9 cm, and 12 cm. Which conclusion is best supported by these results?

  1. Six hours of light is the best amount for every kind of plant
  2. The seedlings grew taller because they were watered more often
  3. Greater average height is linked to more hours of light Correct answer.
  4. Light has no effect on seedling height

Explanation

The data show a consistent increase in average height as daily light increases, which supports a link within this experiment. The results cannot be generalized to all plants or to factors that were not tested.

Question 50The Nature of Science

A student measures the length of a pencil three times with a ruler marked in millimeters and gets 17.4 cm, 17.5 cm, and 17.4 cm. Which reported average is most appropriate?

  1. 17.433333 cm
  2. 17.43 cm
  3. 17.4 cm Correct answer.
  4. 17 cm

Explanation

A calculated result should be reported with no more precision than the measurements allow, and this ruler supports readings to a tenth of a centimeter. Adding extra decimal places suggests precision the instrument cannot provide.