103+ Free Washington Comprehensive Assessment of Science (WCAS) Grade 8 Practice Questions

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2026 Statistics

Key Facts: Washington Comprehensive Assessment of Science (WCAS) Grade 8 Exam

OSPI

State Agency

Washington Office of Superintendent of Public Instruction

Cambium Assessment, Inc.

Test Provider

OSPI WCAP Portal

40 score points

Total Points

WCAS Grade 8 Test Design and Item Specifications (2026)

Scale score 700 (Level 3)

Meets Standard

OSPI Scale Scores for State Assessments

Untimed (~105 min scheduled)

Testing Time

WCAS Grade 8 Test Design and Item Specifications (2026)

April 6 – June 5, 2026 online

2026 Window

OSPI State Testing Timelines and Calendar

English and full Spanish translation

Languages

OSPI Guidelines on Tools, Supports, and Accommodations

103 practice questions

Practice Bank Size

OpenExamPrep

Prepare for the Washington WCAS Science Grade 8 assessment with 103 practice questions weighted to the official 40-point blueprint (Life 38%, Physical 35%, Earth and Space 27%), each with a full explanation.

Sample Washington Comprehensive Assessment of Science (WCAS) Grade 8 Practice Questions

Try these sample questions to test your Washington Comprehensive Assessment of Science (WCAS) Grade 8 exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 103+ question experience with AI tutoring.

1A student burns a 12-gram piece of magnesium ribbon in a sealed flask containing 8 grams of oxygen gas. A bright white flash occurs, producing magnesium oxide powder. What is the total mass of the contents inside the sealed flask after the reaction?

A.20 grams.

B.12 grams.

C.8 grams.

D.4 grams.

Explanation: According to the law of conservation of mass, atoms are neither created nor destroyed in a chemical reaction. The total number and type of atoms in the reactants must equal the total number and type of atoms in the products.

2A 1,000-kg car accelerates from 10 meters per second to 20 meters per second. How does the car's kinetic energy change when its velocity doubles?

A.The kinetic energy quadruples (increases by 4 times).

B.The kinetic energy doubles (increases by 2 times).

C.The kinetic energy remains unchanged.

D.The kinetic energy drops to zero.

Explanation: Kinetic energy (KE) depends linearly on mass and on the square of velocity (KE = 1/2 m v²). Doubling the speed of an object quadruples its kinetic energy.

3A swimmer pushes backward against the pool wall with her feet with a force of 200 Newtons. According to Newton's Third Law, what force does the pool wall exert on the swimmer's feet?

A.200 Newtons forward in the opposite direction.

B.100 Newtons backward in the same direction.

C.0 Newtons because inanimate walls cannot exert forces.

D.400 Newtons upward toward the sky.

Explanation: Newton's Third Law of Motion states that whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object.

4A student observes microscopic cells under a microscope and identifies chloroplasts and a rigid cell wall. Which type of cell is the student observing?

A.A plant cell.

B.A human cheek animal cell.

C.A mammalian red blood cell.

D.A nerve neuron cell.

Explanation: Plant cells contain chloroplasts (site of photosynthesis) and a rigid cell wall made of cellulose, structures absent in animal cells. Both plant and animal cells contain mitochondria, nuclei, and cell membranes.

5Which statement correctly contrasts the outcome of mitosis with meiosis in multicellular organisms?

A.Mitosis creates 2 genetically identical daughter cells, while meiosis creates 4 genetically diverse gametes.

B.Mitosis creates 4 gametes, while meiosis creates 2 identical body cells.

C.Mitosis doubles chromosome count, while meiosis destroys all DNA.

D.Mitosis occurs only in single-celled viruses.

Explanation: Mitosis produces two genetically identical diploid daughter cells for growth and tissue repair. Meiosis produces four genetically diverse haploid gametes (sperm/egg) for sexual reproduction.

6In a population of peppered moths living near industrial towns, dark-colored moths became more common than light-colored moths over several decades. What drove this evolutionary shift?

A.Soot covered tree trunks, giving dark moths better camouflage against bird predators and higher survival rates.

B.Light moths decided to change their gene sequences intentionally to match dark bark.

C.Dark moths ate soot, which chemically turned their offspring black.

D.Bird predators preferred eating dark moths because dark moths tasted better.

Explanation: Natural selection acts on phenotypic variations within a population. Individuals with advantageous traits adapted to environmental pressures survive and reproduce at higher rates, passing favorable alleles to offspring.

7The Cascade Mountain Range in Washington (including Mount Rainier and Mount St. Helens) was formed by which tectonic plate interaction?

A.Subduction at a convergent plate boundary where an oceanic plate slides beneath a continental plate.

B.Seafloor spreading at a mid-ocean divergent boundary.

C.Transform sliding along the San Andreas fault line.

D.Meteor impact cratering forming volcanic cones.

Explanation: Plate tectonics drives continental drift and seafloor spreading. Divergent boundaries create new oceanic crust; convergent boundaries form mountain ranges and subduction zones; transform boundaries cause strike-slip earthquakes.

8Which celestial alignment produces a total lunar eclipse?

A.Sun – Earth – Moon (Earth is directly between the Sun and Moon).

B.Sun – Moon – Earth (Moon is directly between the Sun and Earth).

C.Earth – Sun – Moon (Sun is directly between Earth and Moon).

D.Moon – Sun – Earth (Sun is between Moon and Earth).

Explanation: Solar and lunar eclipses occur when Earth, Moon, and Sun align in a straight line (syzygy). A lunar eclipse occurs during a full moon when Earth passes directly between the Sun and Moon, casting Earth's shadow onto the Moon.

9A geologist examines five horizontal, undisturbed sedimentary rock layers in a canyon wall. According to the Law of Superposition, where is the oldest rock layer located?

A.At the very bottom of the rock formation.

B.At the top of the canyon wall.

C.In the middle layer containing dinosaur fossils.

D.Age is identical across all five rock layers.

Explanation: Rock strata layers obey the Law of Superposition: in undeformed sedimentary rock layers, older layers are deposited at the bottom and younger layers are deposited at the top.

10A city requests design proposals for a new pedestrian footbridge. The bridge must span 30 meters, support up to 5,000 kg, and cost under $150,000. In this engineering challenge, what is the $150,000 budget limit called?

A.A constraint.

B.A criterion.

C.A hypothesis.

D.A variable.

Explanation: Engineering design problems involve defining performance criteria (desired targets) and constraints (limits like cost, materials, time, and safety).

About the Washington Comprehensive Assessment of Science (WCAS) Grade 8 Exam

The Washington Comprehensive Assessment of Science (WCAS) Grade 8 measures student proficiency on the middle school band of the 2013 Washington K–12 Science Learning Standards (Next Generation Science Standards). It assesses all three dimensions across Physical Sciences (chemistry, forces, energy, waves), Life Sciences (cells, heredity, ecosystems, evolution), and Earth and Space Sciences (astronomy, geology, weather and climate, human impacts), with Engineering Design bundled into at least one item cluster. The 40-point fixed-form test is administered online each spring through the WCAP Portal. This 103-question practice bank provides four-option MCQs with detailed explanations as an English-language study adaptation.

Assessment

Untimed online fixed-form state assessment (about 105 minutes of testing time; roughly 135 minutes total administration including directions), given in one to three sessions. Phenomena-based item clusters and standalone items use multiple choice, multiple select, edit-task inline choice, hot text, grid interaction, table match, table input, simulation, and human-scored short answer. Approximately one third of the points are anchor items carried over from previous years, and a scientific calculator and periodic table are embedded. Delivered through the WCAP Portal (Cambium Assessment, Inc.) and aligned to the middle school band of the 2013 Washington K–12 Science Learning Standards. This local bank contains 103 English four-option practice MCQs.

Time Limit

Untimed (about 105 minutes of testing time; ~135 minutes total administration)

Passing Score

No pass/fail score. Scale score 345–1060 with four levels: Level 1 345–649, Level 2 650–699, Level 3 (meets standard) 700–764, Level 4 765–1060.

Exam Fee

No fee to students (Washington Office of Superintendent of Public Instruction (OSPI))

Washington Comprehensive Assessment of Science (WCAS) Grade 8 Exam Content Outline

38% (13–17 of 40 points)

Life Sciences

Cells and body systems, photosynthesis and respiration, matter and energy in ecosystems, heredity and variation, and natural selection and evidence of common ancestry.

35% (12–16 of 40 points)

Physical Sciences

Atoms and molecules, chemical reactions and conservation of mass, forces and motion, energy transfer, and waves and digital information.

27% (9–13 of 40 points)

Earth and Space Sciences

Earth-sun-moon patterns and the solar system, geologic time and plate tectonics, the water cycle, weather, climate and ocean circulation, and natural resources and human impacts.

Bundled (points not specified)

Engineering, Technology, and Applications of Science

MS-ETS1 criteria and constraints, evaluating competing solutions, and iterative optimization, bundled with a science domain inside at least one item cluster.

How to Pass the Washington Comprehensive Assessment of Science (WCAS) Grade 8 Exam

What You Need to Know

Passing score: No pass/fail score. Scale score 345–1060 with four levels: Level 1 345–649, Level 2 650–699, Level 3 (meets standard) 700–764, Level 4 765–1060.
Assessment: Untimed online fixed-form state assessment (about 105 minutes of testing time; roughly 135 minutes total administration including directions), given in one to three sessions. Phenomena-based item clusters and standalone items use multiple choice, multiple select, edit-task inline choice, hot text, grid interaction, table match, table input, simulation, and human-scored short answer. Approximately one third of the points are anchor items carried over from previous years, and a scientific calculator and periodic table are embedded. Delivered through the WCAP Portal (Cambium Assessment, Inc.) and aligned to the middle school band of the 2013 Washington K–12 Science Learning Standards. This local bank contains 103 English four-option practice MCQs.
Time limit: Untimed (about 105 minutes of testing time; ~135 minutes total administration)
Exam fee: No fee to students

Keys to Passing

Work through all 103 available questions
Review every answer and explanation
Track weak areas and revisit them
Use our AI tutor for tough concepts

Washington Comprehensive Assessment of Science (WCAS) Grade 8 Study Tips from Top Performers

1Review how reactant atoms rearrange into product molecules while total mass stays constant in chemical reactions.

2Understand the difference between mitosis (body cells) and meiosis (gametes and genetic diversity).

3Analyze rock strata and fossil layers to determine relative geologic ages.

4Connect solar heating and Earth's rotation to wind patterns and ocean currents.

5Work through the free OSPI Grade 8 training test on the WCAP Portal so the cluster and technology-enhanced item tools are familiar.

Frequently Asked Questions

What is covered on the WCAS Grade 8 test?

It covers the middle school band of the Washington science standards — physical science, life science, Earth and space science, and engineering design — using performance expectations taught across grades 6, 7, and 8.

What score does a Grade 8 student need to meet standard?

A scale score of 700 or higher places a student at Level 3 (meets standard) or Level 4 (exceeds standard). The WCAS is not pass/fail; scores are reported on a 345–1060 scale with four achievement levels.

How long does the WCAS Grade 8 test take?

It is untimed. OSPI schedules about 105 minutes of testing time — 90 minutes for the operational form plus 15 minutes for embedded field-test items — and the test may be split across one to three sessions.

How many questions are on the Grade 8 WCAS?

OSPI does not publish an item count. The blueprint is 40 score points delivered as five item clusters plus six to twelve standalone items, plus embedded field-test items that do not count toward the score.

Can students use a calculator or periodic table?

Yes. A scientific calculator and a periodic table are embedded in the online platform for all Grade 8 WCAS items, and a printable Spanish periodic table is available for students using Spanish supports.

Is this practice bank official?

No. It is an independent 103-question English-language MCQ bank built from the public Washington science standards and the published WCAS blueprint, not an official OSPI product or a simulation of the real item types.