WY-TOPP Summative Science — Grade 8

A student places 10 g of baking soda and 20 g of vinegar into a sealed plastic bottle on a digital balance. A chemical reaction occurs, forming carbon dioxide gas and a liquid solution. What will the digital balance read after the reaction is complete?

• ALess than 30 g because gas escaped
• BExactly 30 g because mass is conserved in a closed container
• CMore than 30 g because new gas was created
• D10 g because vinegar was consumed

Which statement best describes the particle motion and arrangement in a solid ice cube compared to liquid water?

• AParticles in ice move freely in all directions with high kinetic energy.
• BParticles in ice are locked in fixed, rigid positions and vibrate in place.
• CParticles in ice are farther apart and slide past one another easily.
• DParticles in ice have broken apart into individual hydrogen and oxygen atoms.

Which of the following observations provides the clearest evidence that a chemical reaction has occurred rather than a physical change?

• AAn iron nail left outside turns reddish-brown and forms rust.
• BAn ice cube melts into a puddle of liquid water on a warm desktop.
• CA piece of paper is shredded into small confetti strips.
• DTable salt dissolves completely in a glass of warm water.

An atom of carbon has 6 protons, 6 neutrons, and 6 electrons. Which subatomic particles are located inside the nucleus and determine the atom's mass number?

• AProtons and electrons
• BProtons and neutrons
• CNeutrons and electrons
• DElectrons only

A wooden box rests on a flat floor. Student A pushes the box to the right with a force of 10 N, while Student B pushes the box to the left with a force of 4 N. What is the net force acting on the box?

• A14 N to the right
• B6 N to the right
• C6 N to the left
• D0 N (forces are balanced)

Two toy cars, Car X (mass = 1 kg) and Car Y (mass = 2 kg), roll across a smooth track at the exact same speed of 3 m/s. Which car possesses greater kinetic energy?

• ACar X, because lighter objects move with greater kinetic energy.
• BCar Y, because kinetic energy increases with greater mass at a given speed.
• CBoth cars have equal kinetic energy because their speeds are identical.
• DNeither car has kinetic energy because they are moving on a flat track.

A student places a metal spoon and a plastic spoon into a bowl of hot soup ($85^\circ\text{C}$). After 3 minutes, the handle of the metal spoon feels hot, while the handle of the plastic spoon remains cool. Why does this occur?

• AMetal is a good thermal conductor that rapidly transfers thermal energy, while plastic is…
• BMetal creates its own heat energy when placed in liquid, while plastic absorbs cold air.
• CPlastic repels heat molecules, while metal attracts them.
• DThermal energy flows from the cool room air into the metal spoon.

A sound technician increases the amplitude of a sound wave playing through a speaker. How does this change affect the sound heard by the audience?

• AThe pitch of the sound becomes higher.
• BThe loudness of the sound increases.
• CThe speed of the sound wave doubles.
• DThe wavelength of the sound wave becomes shorter.

When a beam of light passes from air into a glass of water, the light beam bends at the boundary between the two materials. What is this phenomenon called?

• AReflection
• BRefraction
• CDiffraction
• DAbsorption

A solid rectangular block has a mass of 120 g and a volume of 40 $\text{cm}^3$. What is the density of the block?

• A0.33 g/$ ext{cm}^3$
• B3.0 g/$ ext{cm}^3$
• C80 g/$ ext{cm}^3$
• D4,800 g/$ ext{cm}^3$

Which cell organelle is known as the 'powerhouse of the cell' because it carries out cellular respiration to convert food energy into usable ATP energy?

• AChloroplast
• BMitochondrion
• CNucleus
• DRibosome

A plant cell contains green organelles called chloroplasts. What primary life process occurs inside the chloroplasts?

• ACellular respiration
• BPhotosynthesis
• CProtein synthesis
• DCell division

What are the primary starting materials (reactants) required for green plants to perform photosynthesis?

• AGlucose and oxygen
• BCarbon dioxide and water
• COxygen and water
• DNitrogen and glucose

In a forest ecosystem web, grass plants absorb sunlight to produce sugar, grasshoppers eat the grass, and meadow larks eat the grasshoppers. What role do the grass plants play?

• APrimary consumer
• BProducer
• CSecondary consumer
• DDecomposer

In a food chain diagram (Plant $\rightarrow$ Rabbit $\rightarrow$ Fox), what do the arrows represent?

• AThe physical direction animals walk to find food
• BThe flow of energy and nutrients from one organism to another
• CThe relative size of each organism
• DThe evolutionary history of the species

Honeybees collect nectar from apple blossoms for food. As they move between flowers, pollen sticks to their bodies and pollinates other blossoms, allowing apple trees to produce seeds. What type of symbiotic relationship is this?

• AParasitism
• BMutualism
• CCommensalism
• DPredation

A hydra reproduces by budding, creating a small outgrowth that breaks off to become an independent organism. How does the genetic makeup of the new hydra compare to the parent?

• AIt has double the genetic material of the parent.
• BIt is genetically identical to the parent.
• CIt contains a combination of genes from two parents.
• DIt has half the chromosomes of the parent.

In pea plants, tall height ($T$) is dominant over short height ($t$). If a heterozygous tall plant ($Tt$) is crossed with a short plant ($tt$), what percentage of the offspring are expected to be short?

• A0%
• B25%
• C50%
• D100%

A geologist analyzes sedimentary rock layers in a canyon wall. According to the Law of Superposition, where would you expect to find the oldest fossils?

• AIn the top rock layer
• BIn the bottom rock layer
• CIn the middle rock layer
• DFossils are evenly aged throughout all layers

A population of beetles lives in a dark forest. A mutation causes some beetles to be dark brown while others are bright yellow. Birds easily spot and eat the yellow beetles. Over several generations, what will likely happen to the beetle population?

• AThe yellow beetles will become more common.
• BThe dark brown beetles will become more common because they survive and reproduce.
• CThe beetles will stop reproducing entirely.
• DThe yellow beetles will mutate back into plants.

Which fundamental force keeps Earth and other planets in predictable orbits around the Sun?

• AFrictional force
• BGravitational force
• CMagnetic force
• DNuclear force

What is the primary cause of Earth's changing seasons throughout the year?

• AEarth's distance from the Sun changes dramatically every month.
• BEarth's axis is tilted at $23.5^\circ$ as it revolves around the Sun.
• CThe Sun turns off its heat during the winter season.
• DOcean currents reverse direction every six months.

During which moon phase is the Moon positioned directly between Earth and the Sun, causing its lit hemisphere to face completely away from Earth?

• AFull Moon
• BNew Moon
• CFirst Quarter
• DWaxing Gibbous

Which water cycle process occurs when liquid water on Earth's surface absorbs thermal energy from the Sun and transforms into water vapor in the atmosphere?

• ACondensation
• BEvaporation
• CPrecipitation
• DRunoff

Layered rocks containing visible shell fragments, sand grains, and mud settled at the bottom of an ancient lake are classified as which rock type?

• AIgneous rock
• BSedimentary rock
• CMetamorphic rock
• DVolcanic rock

At the Mid-Atlantic Ridge, tectonic plates move apart from one another, allowing magma to rise from the mantle and cool into fresh oceanic crust. What type of plate boundary is this?

• AConvergent boundary
• BDivergent boundary
• CTransform boundary
• DSubduction zone

Which meteorological instrument is specifically used by scientists to measure atmospheric air pressure?

• AThermometer
• BBarometer
• CAnemometer
• DHygrometer

Which set of energy resources consists entirely of renewable resources that naturally replenish on short human timescales?

• ACoal, natural gas, and petroleum
• BSolar, wind, and hydroelectric energy
• CNuclear power, coal, and solar energy
• DPetroleum, wind, and geothermal energy

What specific celestial alignment occurs during a total solar eclipse?

• AEarth passes directly between the Sun and the Moon.
• BThe Moon passes directly between the Sun and Earth, casting a shadow on Earth.
• CThe Sun passes between Earth and the Moon.
• DJupiter blocks the Sun from Earth.

How does large-scale deforestation (clearing trees) impact Earth's atmospheric carbon dioxide levels?

• AIt decreases atmospheric carbon dioxide because dead trees stop producing gas.
• BIt increases atmospheric carbon dioxide because fewer trees are available to absorb $ ext…
• CIt has zero impact because carbon dioxide is only affected by volcanoes.
• DIt converts all carbon dioxide into atmospheric oxygen.

A student mixes 50 mL of solution A ($22^\circ\text{C}$) with 50 mL of solution B ($22^\circ\text{C}$) in an insulated beaker. Within 30 seconds, bubbles form, a white precipitate settles at the bottom, and the temperature drops to $14^\circ\text{C}$. How should this reaction be classified?

• AAn exothermic physical change
• BAn endothermic chemical reaction
• CAn exothermic chemical reaction
• DAn endothermic physical change

Consider the balanced chemical equation for the combustion of methane: $\text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O}$. How many total oxygen atoms are present in the reactants, and how many are in the products?

• A2 reactant oxygen atoms; 2 product oxygen atoms
• B4 reactant oxygen atoms; 4 product oxygen atoms
• C4 reactant oxygen atoms; 2 product oxygen atoms
• D8 reactant oxygen atoms; 8 product oxygen atoms

Synthetic polymers, such as polyethylene plastic bottles, are manufactured from natural petroleum crude oil. Which comparison between natural crude oil and synthetic plastic is accurate?

• ACrude oil and plastic have identical chemical structures and physical properties.
• BSynthetic plastic is synthesized through chemical processing of petroleum hydrocarbons, g…
• CSynthetic plastic forms naturally underground without human processing.
• DCrude oil is a synthetic material created in laboratories, while plastic is a natural min…

A 4 kg shopping cart is pushed across a smooth level floor with a constant net force of 12 N. Using Newton's Second Law ($F_{net} = ma$), what is the resulting acceleration of the shopping cart?

• A0.33 m/$ ext{s}^2$
• B3.0 m/$ ext{s}^2$
• C8.0 m/$ ext{s}^2$
• D48.0 m/$ ext{s}^2$

A swimmer stands on the edge of a boat and leaps forward into the water. According to Newton's Third Law of Motion, what happens to the boat?

• AThe boat moves forward in the same direction as the swimmer with equal speed.
• BThe boat pushes backward against the water, moving backward with an equal and opposite fo…
• CThe boat remains completely stationary because the swimmer's feet leave the deck.
• DThe boat sinks vertically downward beneath the water level.

The gravitational attraction between two asteroids separated by a distance $d$ is measured as $F$. If the distance between the two asteroids is doubled to $2d$, how does the gravitational force between them change?

• AThe gravitational force doubles ($2F$).
• BThe gravitational force is reduced to one-half ($0.5F$).
• CThe gravitational force is reduced to one-fourth ($0.25F$).
• DThe gravitational force remains unchanged.

A student places two bar magnets on a smooth surface. When the North pole of Magnet 1 is brought near the South pole of Magnet 2, what magnetic interaction occurs?

• AThe poles repel each other and push apart.
• BThe poles attract each other and pull together.
• CThe magnetic field lines disappear entirely.
• DThe magnets rotate until both North poles touch.

Calculate and compare the kinetic energy of Object A (mass = 2 kg, velocity = 4 m/s) and Object B (mass = 4 kg, velocity = 2 m/s). Which statement is correct?

• AObject A has $KE = 16\text{ J}$; Object B has $KE = 8\text{ J}$; Object A has greater kin…
• BObject A has $KE = 8\text{ J}$; Object B has $KE = 16\text{ J}$; Object B has greater kin…
• CBoth objects have identical kinetic energy ($KE = 16\text{ J}$).
• DBoth objects have identical kinetic energy ($KE = 8\text{ J}$).

A roller coaster cart starts from rest at the top of Hill 1 (height = 30 m), rolls down to the lowest point of the track (height = 0 m), and climbs Hill 2. Ignoring friction, how do the cart's potential energy (PE) and kinetic energy (KE) change as it rolls from the top of Hill 1 to the bottom?

• APE decreases while KE increases, keeping total mechanical energy constant.
• BPE increases while KE decreases, keeping total mechanical energy constant.
• CBoth PE and KE increase simultaneously as speed increases.
• DBoth PE and KE drop to zero at the bottom of the hill.

A pot of water is heated on an electric stove. As water near the bottom of the pot warms up, it expands, becomes less dense, and rises. Cooler, denser water at the top sinks to replace it. What method of heat transfer is creating this circulating current?

• AConduction
• BConvection
• CRadiation
• DInsulation

A water wave travels across a pond at a speed of 6 m/s. If the frequency of the wave is 2 Hz (2 waves per second), what is the wavelength of the water wave? (Use wave speed equation: $v = f \times \lambda$)

• A0.33 m
• B3.0 m
• C8.0 m
• D12.0 m

Modern telecommunication systems transmit information using digital signals (0s and 1s) rather than continuous analog signals. What is a primary advantage of digital signals for transmitting data over long distances?

• ADigital signals travel faster than the speed of light.
• BDigital signals can be easily filtered to remove noise and distortion because distinct hi…
• CDigital signals do not require any energy to transmit.
• DDigital signals can only be sent through copper wires, avoiding wireless interference.

The electromagnetic spectrum includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. Which statement correctly compares radio waves and X-rays?

• ARadio waves have shorter wavelengths and higher frequencies than X-rays.
• BX-rays have higher frequencies, shorter wavelengths, and carry significantly higher energ…
• CRadio waves and X-rays carry identical energy because both are electromagnetic waves.
• DX-rays travel much faster through a vacuum than radio waves.

A student consults a solubility curve graph. At $20^\circ\text{C}$, a maximum of 36 g of Salt X dissolves in 100 g of water. If the student adds 45 g of Salt X to 100 g of water at $20^\circ\text{C}$ and stirs thoroughly, what will be observed?

• AAll 45 g will dissolve, forming an unsaturated solution.
• B36 g will dissolve, and 9 g of undissolved Salt X will settle at the bottom of the beaker…
• CThe water will freeze solid instantly.
• DThe salt will react with water to form hydrogen gas.

In a simple electric circuit powered by a 9 V battery, a light bulb has a resistance of 3 $\Omega$. According to Ohm's Law ($V = I \times R$), what electrical current flows through the circuit?

• A0.33 A
• B3.0 A
• C6.0 A
• D27.0 A

A pendulum swings back and forth. At its highest point on the left, it pauses for an instant before swinging downward. Over 20 swings, the maximum height of the pendulum gradually decreases until it stops. What happened to the mechanical energy of the pendulum?

• AMechanical energy was completely destroyed in violation of conservation laws.
• BFriction and air resistance transformed mechanical energy into thermal energy in the air…
• CThe kinetic energy converted into gravitational potential energy that disappeared.
• DThe mass of the pendulum bob decreased with every swing.

Which table correctly matches the relative mass and electric charge of the three primary subatomic particles?

• AProton (+1 charge, ~1 amu); Neutron (0 charge, ~1 amu); Electron (-1 charge, ~0 amu)
• BProton (0 charge, ~1 amu); Neutron (+1 charge, ~1 amu); Electron (-1 charge, ~1 amu)
• CProton (-1 charge, ~0 amu); Neutron (0 charge, ~1 amu); Electron (+1 charge, ~1 amu)
• DProton (+1 charge, ~0 amu); Neutron (-1 charge, ~1 amu); Electron (0 charge, ~1 amu)

A red blood cell (water concentration = 99%) is placed into a beaker containing a concentrated 10% saltwater solution (water concentration = 90%). What will happen to the cell due to osmosis across the semi-permeable cell membrane?

• AWater will move out of the cell into the beaker, causing the cell to shrink.
• BWater will move into the cell from the beaker, causing the cell to swell and burst.
• CSalt molecules will rapidly enter the cell until it doubles in size.
• DNo water movement will occur because cell membranes block water.