Models: Strengths and Limitations

Question 1

A plant cell model is a stiff cardboard box, lined inside with a water-filled plastic bag, with a plum taped in the center for the nucleus. Which feature of a real plant cell does it show well?

Accepted Answer

A stiff outer wall surrounds a flexible membrane holding watery contents.

Answer

Chloroplasts in the cytoplasm capture light energy to make food.

Answer

Tiny pores through the wall link the cell to its neighbors.

Answer

Ribosomes spread through the cytoplasm build the cell's proteins.

Question 2

A sealed clear box holds warm water, with a tray of ice resting on its lid. Drops form under the lid and fall back. Which part of the real water cycle does this show well?

Accepted Answer

Water evaporates, condenses on a cooler surface, and falls back as liquid.

Answer

Rain soaks into the ground and moves slowly through soil and rock.

Answer

Rivers carry water downhill from mountains to the ocean.

Answer

Winds carry water vapor thousands of kilometers before it falls as rain.

Question 3

Two wooden blocks with sandpaper glued to their touching faces are pushed steadily together until they suddenly jerk past each other. They model a fault. Which feature of real faults does this show well?

Accepted Answer

Stress builds along a rough boundary and is released in a sudden slip.

Answer

Molten rock rises through a crack and builds a volcanic cone.

Answer

Rock layers fold slowly into rounded hills over millions of years.

Answer

Seismic waves travel outward through the whole planet after a quake.

Question 4

Sawdust is stirred into a pan of water heated by a burner under one edge. The sawdust rises above the burner, crosses the top and sinks. Which feature of mantle convection does this show well?

Accepted Answer

Material heated from below rises, moves sideways, cools and sinks in a loop.

Answer

Mantle rock stays solid even while it slowly changes position over long spans of time.

Answer

Heat crosses the mantle as radiation beamed out from the core.

Answer

Plates split apart where new crust forms at a mid-ocean ridge.

Question 5

An atom model has a ping-pong ball glued at the center of a wire cage, with small beads fixed on the wires. Which feature of a real atom does this model show well?

Accepted Answer

Electrons are found in the space outside a central nucleus.

Answer

Each electron sits at one fixed point on its own wire and never moves from it.

Answer

The nucleus fills up most of the volume of the atom.

Answer

An electron has almost the same mass as a proton.

Question 6

An arm model has two cardboard strips joined by a paper fastener, with one rubber band across the joint. Shortening the band raises the lower strip. Which feature of a real arm does this show well?

Accepted Answer

A muscle crossing a hinge joint pulls one bone toward another as it shortens.

Answer

Muscles work in opposing pairs, so another muscle pulls the bone back.

Answer

Nerve signals from the brain trigger the muscle to contract.

Answer

Marrow inside the arm bones produces new blood cells.

Question 7

A hard-boiled egg models Earth's interior: shell for crust, white for mantle, yolk for core. Which feature of Earth's interior does this model fail to show?

Accepted Answer

The mantle slowly flows and churns, while the egg white stays still.

Answer

The crust is thin compared with the much thicker layers that lie beneath it.

Answer

The core lies at the center of the planet.

Answer

The layers form rounded shells one inside another.

Question 8

A food chain model shows four cards in one straight line: grass, grasshopper, frog, hawk, joined by single arrows. Which feature of a real meadow ecosystem does this model fail to show?

Accepted Answer

Most animals eat several kinds of food, so feeding links branch and cross.

Answer

Energy passes along the line from each organism to the one that eats it.

Answer

A producer stands at the start of the feeding sequence.

Answer

A hawk can be the last consumer in a feeding sequence.

Question 9

A DNA model is two pipe cleaners twisted around each other, with colored beads paired between them. Which feature of real DNA does this model fail to show?

Accepted Answer

The two strands separate so each can be copied before a cell divides.

Answer

Two strands wind around each other in a spiral.

Answer

Each base is joined to one matching partner across the strands.

Answer

The two strands stay the same distance apart along their length.

Question 10

A cart is pushed once along a level classroom track; it rolls, slows and stops. It models a spacecraft coasting far from any star. Which feature of the real motion does this model fail to show?

Accepted Answer

With no force acting on it, the spacecraft keeps a steady speed indefinitely.

Answer

A push is needed to change the spacecraft's speed.

Answer

The coasting spacecraft travels along a straight path through empty space.

Answer

The spacecraft's mass stays the same while it coasts.

Question 11

A breathing model is a plastic bottle holding a balloon, with a rubber sheet across its open base; pulling the sheet down inflates the balloon. Which feature of real lungs does it fail to show?

Accepted Answer

Oxygen passes from tiny air sacs into blood vessels wrapped around them.

Answer

Air is drawn in when the space around the lungs gets larger.

Answer

The lungs sit inside a closed space bounded below by the diaphragm.

Answer

Air reaches the lungs through a tube leading in from outside.

Question 12

Colored sand is poured in layers into a jar, with plastic beads dropped in as fossils. It models rock layers. Which feature of real rock layers does this model fail to show?

Accepted Answer

Layers of similar thickness can take very different lengths of time to form.

Answer

Older layers lie beneath younger ones.

Answer

Remains of organisms are buried inside the layers as those layers build up.

Answer

Layers build up one above another over time.

Question 13

A circuit is modeled by water pumped around closed pipes, with a narrow pipe section standing for the bulb. Which feature of a real circuit does this model fail to show?

Accepted Answer

A break in the loop stops the current at once, with nothing spilling out.

Answer

A source drives the flow around a complete loop.

Answer

A part with high resistance reduces the flow everywhere in the loop.

Answer

The flow is the same at every point of a single loop.

Question 14

A teacher wants students to compare the size of the Sun with the size of Earth. Which model serves that purpose best?

Accepted Answer

A one meter exercise ball for the Sun beside a 9 mm bead for Earth

Answer

A 30 cm ball for the Sun beside a 3 cm marble for Earth

Answer

Markers spaced along a hallway by scaled orbital distance

Answer

A lamp with a globe turning beside it in a darkened room

Question 15

A teacher wants students to see how a slowing stream sorts sediment by particle size. Which model serves that purpose best?

Accepted Answer

A clear tube of mixed gravel, sand and silt in water, shaken then left to settle

Answer

A tray of dry sand blown across with a straw

Answer

A photograph of a riverbank showing exposed bands of gravel, sand and silt

Answer

A jar of mixed gravel, sand and silt kept stirred so nothing settles

Question 16

A teacher wants students to see how a color trait becomes more common in a population over several generations. Which model serves that purpose best?

Accepted Answer

Paper dots scattered on patterned cloth, picked up quickly each round, with the survivors doubled

Answer

A photograph of two moths of different colors resting side by side on a dark tree trunk

Answer

Two beakers of colored water poured together and stirred

Answer

A drawn family tree of eye color across three generations

Question 17

A teacher wants students to see why the Moon's lit shape changes through the month. Which model serves that purpose best?

Accepted Answer

A student turning slowly while holding a white ball at arm's length under one bright lamp

Answer

A ball moved between a lamp and a globe until the ball's shadow falls across the globe

Answer

A poster showing the eight phases in a row with their names

Answer

A globe spun beside a lamp to show day turning into night

Question 18

A model of Earth uses a 30 cm globe wrapped in a 5 cm thick foam shell for the atmosphere. The real atmosphere lies within 1 percent of Earth's diameter. What does the scale get wrong?

Accepted Answer

The atmosphere is drawn far thicker than it really is compared with Earth.

Answer

Earth is shown far smaller than its real size.

Answer

The atmosphere is shown surrounding the whole planet rather than sitting over one region

Answer

The atmosphere is placed above the solid surface.

Question 19

A water molecule model has three plastic balls joined by rigid rods at a fixed angle. What do the model's materials get wrong about a real water molecule?

Accepted Answer

Real bonds are not solid bars; the atoms constantly vibrate and the angle flexes.

Answer

Two hydrogen atoms are joined to a single oxygen atom.

Answer

The two hydrogen atoms sit on the same side of the single oxygen atom at the center

Answer

The atoms are held together rather than drifting apart.

Question 20

A bridge truss is built from drinking straws and loaded with weights, to predict how a steel bridge of the same design will behave. What does the model's material get wrong?

Accepted Answer

Straws buckle at loads far below steel's, so the measured load cannot be scaled up.

Answer

The triangles are arranged in the same repeating pattern as those in the real steel truss.

Answer

The supports sit at each end of the span.

Answer

The deck is longer than it is wide.

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Models: Strengths and Limitations

Ways to Play

Device Games: Students play on their phones

Blast Go

Zombie Escape

Avalanche

Maze Blast

Cave Climb

Blast Out

Mystery Auction

Tour Guide

Food Truck Rush

Tug of War

Alien Blast

Glacier Rush

Board Games: Teacher-led, projected to the class

Like what you see?

Bug Blast

BlastRace

BlastQuiz

BlastBoard

Seek & Destroy

Mystery Blast

Checkers

Texas Hold 'Em

Da Bomb

Castle Siege

Hot Potato

Market Mayhem

King of the Hill

Bank Heist

Top Corner

Models: Strengths and Limitations

Ways to Play

Device Games: Students play on their phones

Blast Go

Zombie Escape

Avalanche

Maze Blast

Cave Climb

Blast Out

Mystery Auction

Tour Guide

Food Truck Rush

Tug of War

Alien Blast

Glacier Rush

Board Games: Teacher-led, projected to the class

Like what you see?

More like this

Bug Blast

BlastRace

BlastQuiz

BlastBoard

Seek & Destroy

Mystery Blast

Checkers

Texas Hold 'Em

Da Bomb

Castle Siege

Hot Potato

Market Mayhem

King of the Hill

Bank Heist

Top Corner