Washington Comprehensive Assessment of Science — Grade 5

A student dissolves a spoonful of sugar into a cup of warm water until the sugar can no longer be seen. Which statement best explains what happened to the sugar?

• AThe sugar broke apart into tiny particles that spread out evenly among the water particle…
• BThe sugar changed into water particles and ceased to exist as sugar.
• CThe sugar dissolved by destroying the water particles at the bottom of the cup.
• DThe sugar evaporated out of the cup into the surrounding air.

A student measures the mass of a sealed jar containing 100 grams of ice cubes. After the ice completely melts into liquid water inside the sealed jar, what will the total mass of the water and jar be?

• AThe exact same mass as before the ice melted.
• BLess than before because liquid water is less dense than ice.
• CMore than before because liquid water occupies less volume.
• DZero grams because phase changes destroy mass.

A student drops a tennis ball from a height of two meters. Which statement correctly describes the force acting on the ball as it falls?

• AEarth's gravity exerts a downward force pulling the ball toward Earth's center.
• BAir pressure pushes the ball down toward the ground.
• CMagnetic forces between the ball and the ground pull the ball down.
• DThe ball moves down because it loses all of its internal energy.

A scientist grows a potted plant from a seed in a sealed container with air, light, and water. Over several months, the plant gains 500 grams of mass while the dry soil loses less than 1 gram. Where did the plant get most of the matter for its growth?

• AFrom carbon dioxide in the air and water absorbed by roots.
• BFrom solid soil minerals absorbed directly into leaves.
• CFrom sunlight changing directly into solid matter.
• DFrom fertilizer particles produced inside the plant stem.

Which role in a forest ecosystem food web directly converts light energy from the Sun into chemical energy stored in food?

• AProducers such as evergreen trees and ferns.
• BPrimary consumers such as snowshoe hares.
• CDecomposers such as mushrooms and soil bacteria.
• DApex predators such as cougars and wolves.

The Sun appears much larger and brighter in Earth's sky than distant stars like Rigel or Sirius, even though some distant stars produce much more light. Why does the Sun appear so much brighter?

• AThe Sun is much closer to Earth than any other star.
• BThe Sun is the only star made of glowing hot gases.
• CThe Sun reflects light from Earth's atmosphere back to space.
• DDistant stars only emit light during nighttime hours.

A student measures the shadow of a flagpole at 8:00 AM, 12:00 PM, and 4:00 PM. What causes the length and position of the flagpole's shadow to change throughout the day?

• AEarth rotating on its axis as it orbits the Sun.
• BThe Sun moving closer to and farther from Earth every hour.
• CEarth's distance from the Moon changing throughout the day.
• DCloud cover altering the speed of light hitting the flagpole.

Where is the vast majority of Earth's total water supply stored?

• AIn oceans as salt water.
• BIn freshwater rivers and lakes.
• CIn atmospheric water vapor and clouds.
• DIn underground aquifers as drinkable fresh water.

Rain falls on a rocky mountain slope, soaking into the soil and providing water for pine trees growing there. Which Earth spheres are directly interacting in this example?

• AHydrosphere, geosphere, and biosphere.
• BAtmosphere and exosphere only.
• CCryosphere and magnetosphere only.
• DBiosphere and asthenosphere only.

A student wants to test which shape of paper airplane flies the farthest distance. To make the test fair, which factor should the student change between flights?

• AOnly the fold shape of the paper airplane.
• BThe paper airplane shape and the type of paper used.
• CThe throwing strength, airplane shape, and indoor location.
• DAll features of the airplane and flight conditions simultaneously.

A student mixes vinegar and baking soda in a flask. Gas bubbles rapidly form and the temperature of the liquid drops. Which statement provides the best evidence that a chemical change occurred?

• AA new gas substance was produced that was not present before mixing.
• BThe baking soda dissolved in the liquid without changing identity.
• CThe total mass of the mixture doubled after mixing.
• DThe liquid expanded because the flask shrank in size.

A student puts 15 grams of baking soda and 100 grams of vinegar into a zip-top plastic bag and seals it tightly. The bag inflates with gas as the substances react. What is the total mass of the sealed bag and its contents after the reaction stops?

• A115 grams, plus the mass of the empty plastic bag.
• BLess than 115 grams because gas has negative weight.
• CMore than 115 grams because the bag expanded with air.
• DZero grams because matter was converted entirely into energy.

A student pulls a loaded sled across flat, snowy ground so that it moves in a straight line at a steady speed. What can the student conclude about the forces acting on the sled?

• AThe forward pull and the backward friction are balanced, so the sled's motion does not ch…
• BOnly the forward pull acts on the sled, because friction disappears once the sled is movi…
• CThe backward friction must be larger than the forward pull for the sled to keep moving.
• DNo forces act on the sled at all, which is why its speed stays the same.

Two students standing on opposite sides of Earth (one in Washington State and one in southern Australia) drop apples at the exact same moment. In which direction does gravity pull each apple?

• ABoth apples are pulled downward toward the center of Earth.
• BBoth apples fall toward the South Pole.
• CThe apple in Washington falls down, while the apple in Australia falls up into space.
• DGravity pulls both apples toward the Sun.

A hawk eats a garter snake, which ate a toad, which ate a grasshopper, which ate green grass. Where did the energy stored in the hawk's body originally come from?

• ASunlight captured by the green grass.
• BSoil nutrients absorbed by the toad.
• CThermal heat generated inside the snake.
• DAir pressure absorbed by the hawk during flight.

If all decomposers (fungi and soil bacteria) were completely removed from a forest ecosystem, what would be the most immediate long-term problem for the forest?

• ADead trees and fallen leaves would pile up, and soil would run out of recycled nutrients…
• BHerbivores would multiply rapidly because predators would starve.
• CPlants would produce excess oxygen until the atmosphere caught fire.
• DSunlight would no longer reach the Earth's surface.

A student in Washington notices that the constellation Orion is clearly visible in the winter night sky but cannot be seen at night during the summer. What causes this seasonal change?

• AEarth revolving around the Sun, changing the direction night faces in space.
• BThe constellation Orion orbiting Earth once every six months.
• CEarth's atmosphere becoming opaque during summer months.
• DThe Sun blocking stars by turning off its light in winter.

If all water on Earth were represented by 100 liters, approximately how many liters would be available as liquid fresh water in rivers, lakes, and shallow groundwater for human use?

• ALess than 1 liter.
• B30 liters.
• C70 liters.
• D97 liters.

Excess chemical fertilizer applied to farmland washes into a nearby lake during heavy rain, causing an overgrowth of algae that depletes oxygen and harms fish. This scenario illustrates how human land use affects which Earth spheres?

• AHuman activity on the geosphere negatively impacts the hydrosphere and biosphere.
• BAtmospheric pressure increases the salinity of the exosphere.
• CThe cryosphere converts freshwater lakes into saltwater oceans.
• DEarth's magnetic field stops solar radiation from entering the soil.

Engineers are designing a seawall to protect a coastal Washington town from wave erosion. They create three miniature models using different materials: concrete blocks, wooden pilings, and piled boulders. How should they test the models?

• AExpose all three models to identical wave sizes and frequencies, measuring how much wave…
• BTest the concrete blocks with large waves, the wood with small waves, and the boulders wi…
• CChoose the boulder design immediately based on appearance without conducting physical tes…
• DTest each model in different weather conditions and assume the results are identical.

A student places an ice-cold glass of water on a table in a warm room. After 15 minutes, water droplets cover the outside of the glass. Which statement correctly identifies the source and process of this water?

• AWater vapor in the warm air cooled down and condensed onto the cold glass surface.
• BLiquid water inside the glass leaked through microscopic holes in the glass.
• CThe glass created water out of cold energy generated by the ice.
• DHydrogen and oxygen gases chemically reacted on the glass surface to form new water.

A student measures the mass of an unbent glow stick on a digital scale (42.0 grams). The student bends the glow stick, snapping the internal glass capsule, which causes a chemical reaction that produces bright light. After glowing for two hours, what is the mass of the glow stick?

• AExactly 42.0 grams because chemical reactions in sealed containers conserve matter.
• B40.0 grams because mass was destroyed to create light energy.
• C44.0 grams because light adds extra weight to glowing objects.
• D0.0 grams because chemical reactions consume all initial mass.

Why do oceans on the bottom side of Earth's sphere not spill off into outer space?

• AEarth's gravity pulls water inward toward the center of Earth from all surface points.
• BAtmospheric wind pressure pushes ocean water upward against Earth's crust.
• CEarth's rapid magnetic spin creates centrifugal force holding water to the poles.
• DSpace contains vacuum suction that pushes water against the seabed.

In a Washington forest ecosystem, wolves prey on elk, which eat young willow trees along riverbanks. If a viral disease removes all wolves from the ecosystem, what chain of events is most likely to follow?

• AElk populations will increase, leading to overconsumption of willow trees and soil erosio…
• BWillow trees will multiply uncontrollably because wolves are no longer fertilizing the so…
• CElk will immediately switch to eating meat to replace the wolves' ecological niche.
• DSolar energy reaching the forest floor will drop to zero.

A student measures a stick's shadow at 8:00 AM, 12:00 PM (noon), and 5:00 PM on a clear day in June. Which table accurately predicts the relative length of the shadow at these times?

• A8:00 AM: Long; 12:00 PM: Shortest; 5:00 PM: Long.
• B8:00 AM: Shortest; 12:00 PM: Medium; 5:00 PM: Longest.
• C8:00 AM: Medium; 12:00 PM: Longest; 5:00 PM: Shortest.
• DShadow length remains identical at all times of day.

A student rolls a marble down a ramp so that it strikes a second marble sitting still at the bottom. The rolling marble slows down and the resting marble shoots forward. What best explains this result?

• AEnergy of motion was transferred from the rolling marble to the resting marble during the…
• BThe resting marble created brand-new energy inside itself the moment it was struck.
• CThe rolling marble destroyed its own energy, and the second marble moved because of gravi…
• DThe two marbles traded some of their mass, which made the second marble move.

A student receives a dry mixture of small iron filings, sand, and table salt. Which sequence of physical steps will separate all three substances completely?

• AUse a magnet to pull out iron filings, add water to dissolve salt, filter out the sand, t…
• BHeat the mixture until sand melts, pour off the liquid salt, then pick out iron filings w…
• CAdd vinegar to burn away sand, use a sifter for salt, then freeze the iron filings.
• DDissolve all three materials in water, filter the liquid, then freeze the remaining mixtu…

Which event is an example of a chemical change?

• AAn iron nail rusting after being left in damp soil.
• BA glass marble shattering into small pieces on concrete.
• CLiquid water freezing into ice cubes in a freezer.
• DChopping a wooden log into smaller kindling sticks.

Which plant structure is specialized to absorb light energy from the Sun for producing food?

• AGreen leaves containing chlorophyll.
• BRoot hairs buried deep in soil.
• CWoody bark protecting the stem.
• DPetals attracting insect pollinators.

Mount St. Helens in Washington State erupts, releasing molten lava, rock fragments, and volcanic ash. Which Earth sphere is the source of this lava and rock?

• AThe geosphere.
• BThe hydrosphere.
• CThe atmosphere.
• DThe exosphere.

A student drops pebbles into a tub of water and draws the ripples that spread out. A large pebble makes ripples that rise much higher above the still-water line than the ripples made by a small pebble. Which wave property did the large pebble increase?

• AThe amplitude, which is the height of the wave above the still-water line.
• BThe wavelength, which is the distance from one wave crest to the next crest.
• CThe number of pebbles needed to make the water move at all.
• DThe depth of the tub, which the ripples push downward as they travel.

A student builds an electromagnet by wrapping copper wire around an iron nail and connecting it to a battery. How can the student increase the magnetic attraction force of the nail to lift more paperclips?

• AIncrease the number of wire loops wrapped tightly around the nail.
• BUnwrap half of the wire loops from the nail.
• CDisconnect the battery and replace the iron nail with a plastic straw.
• DCool the nail in water until it turns into ice.

A student wants to keep hot soup warm for lunch. Which material spoon should the student leave inside the soup thermos to slow down heat loss?

• AA wooden or plastic spoon, because wood and plastic are poor conductors of heat.
• BA copper spoon, because copper conducts heat very rapidly.
• CAn aluminum spoon, because metals absorb cold from the surrounding air.
• DA silver spoon, because polished silver reflects all thermal energy back into soup.

A student shines a flashlight beam at three different sheets: clear glass, waxed paper, and thick cardboard. Which sheet will cast the darkest, clearest shadow on the wall behind it?

• AThe thick cardboard, because it is opaque and blocks light from passing through.
• BThe clear glass, because it reflects all light back toward the flashlight.
• CThe waxed paper, because translucent materials absorb all light rays.
• DAll three sheets will cast identical black shadows.

A student connects a battery, copper wire, lightbulb, and switch in a simple series loop. When the switch is opened, the lightbulb turns off immediately. Why does the lightbulb turn off?

• AOpening the switch creates a break in the circuit path, stopping electrical current flow.
• BOpening the switch drains all electrical energy stored in the battery instantaneously.
• COpening the switch reverses gravity inside the copper wire.
• DOpening the switch converts copper metal into rubber insulation.

In a Puget Sound marine ecosystem, phytoplankton are eaten by zooplankton, zooplankton are eaten by herring, and herring are eaten by harbor seals. Which organism functions as the primary producer?

• APhytoplankton.
• BZooplankton.
• CHerring.
• DHarbor seals.

A student covers all the leaves of a healthy houseplant with waterproof petroleum jelly, blocking all microscopic pores (stomata) on the leaves. What will happen to the plant over the next two weeks?

• AThe plant will yellow and stop growing because it cannot take in carbon dioxide gas from…
• BThe plant will grow twice as fast because it traps extra water inside its stems.
• CThe plant will produce double the amount of oxygen gas into the soil.
• DThe roots will immediately start performing photosynthesis underground.

Nutria (large non-native rodents) were introduced into Washington wetlands. Nutria consume large amounts of aquatic vegetation along shorelines, destroying duck nesting habitats. How do nutria affect the wetland ecosystem?

• ANutria compete with native waterfowl for plant resources, reducing native duck population…
• BNutria increase biodiversity by generating solar energy for native plants.
• CNutria convert saltwater wetlands into freshwater mountain rivers.
• DNutria protect native ducks by hunting all local eagles and hawks.

Dandelion seeds have light, feathery structures attached to them. Which natural vector primarily aids dandelion seed dispersal over wide areas?

• AWind currents carrying seeds through air.
• BUnderground river currents pulling seeds into rocks.
• CHeavy snow falling directly on top of flower heads.
• DEarthquakes shaking seeds into volcanic magma.

Which organ system structure enables salmon swimming in Washington rivers to absorb dissolved oxygen gas from water?

• AGills.
• BScales.
• CLungs.
• DFins.

Why is it warmer in Washington State during July than during January?

• AThe Northern Hemisphere is tilted toward the Sun in July, receiving more direct sunlight…
• BEarth is millions of miles closer to the Sun in July than in January.
• CThe Sun burns twice as hot during summer months.
• DEarth stops rotating during July, allowing heat to build up continuously.

What causes the apparent shape of the illuminated Moon to change systematically over a 29-day month?

• AThe Moon revolving around Earth, changing the angle from which we view its sunlit half.
• BEarth's shadow blocking parts of the Moon every single night.
• CClouds in Earth's upper atmosphere covering different fractions of the Moon.
• DThe Moon expanding and shrinking in physical size as it rotates.

Of all the fresh water present on planet Earth, where is the largest percentage frozen and stored?

• AIn glaciers and ice sheets (cryosphere).
• BIn deep freshwater lakes like Lake Washington.
• CIn major river systems like the Columbia River.
• DIn atmospheric rain clouds.

A community notices that rainstorms are washing topsoil off a bare hillside into a river. How can planting native shrubs and grasses on the hillside reduce soil erosion?

• APlant roots anchor soil particles in place and foliage slows down impact speed of raindro…
• BPlants absorb all gravity, stopping rain from falling onto the hillside.
• CPlants convert topsoil into heavy granite bedrock.
• DPlants push rain clouds away from the hillside using oxygen gas.

Washington State generates a large percentage of its electricity using hydroelectric dams on the Columbia River. Which type of natural resource powers hydroelectric turbines?

• AA renewable resource (flowing water).
• BA non-renewable resource (coal).
• CA finite resource (petroleum crude oil).
• DA fossil fuel resource (natural gas).

A student team is challenged to build a bridge out of 50 wooden popsicle sticks and craft glue that can hold a 2-kilogram weight. In this challenge, what is the 50-stick limit called?

• AA constraint (a limitation or rule on the design).
• BA criterion (a success requirement).
• CA hypothesis (an educated guess).
• DA conclusion (a final test result).

A student builds a toy solar car, but during its first test track run, the car moves very slowly and stops. What should the student do next in the engineering design process?

• AIdentify which parts of the car cause friction or receive poor light, modify those specif…
• BThrow the car away and give up on solving the problem.
• CDeclare the test a success without recording speed or distance data.
• DWrite a paper claiming solar energy is impossible to use for vehicle movement.