GIZMOS DIFFUSION STUDENT
EXPLORATION COMPLETE EXAM 151
to 200 2026 2027 CAPSTONE
SYNTHESIS AND ADVANCED
APPLICATIONS A+ VERIFIED
GIZMOS Student Exploration: Diffusion | Practice Exam
Questions [2026/2027]
1. A student opens the Diffusion Gizmo and observes gas particles
moving randomly in two connected chambers separated by a partial wall.
After 60 seconds, the student notices that particles have moved from
Region A (initially 100 particles) to Region B (initially 0 particles).
Which statement BEST explains why this movement occurred without
any external force applied?
A) Particles were actively transported by cellular energy (ATP) from high
to low concentration
B) Particles moved randomly due to kinetic energy, resulting in net
movement down the concentration gradient
C) Gravity pulled particles from Region A to Region B until
concentrations equalized
D) An electrical charge difference attracted particles from Region A to
Region B
Answer: B) Particles moved randomly due to kinetic energy, resulting in
net movement down the concentration gradient
Rationale: Diffusion is a passive process driven by the inherent kinetic
energy of particles. Random motion causes more particles to move from
high to low concentration simply due to probability, creating net
movement without external energy input. Active transport, gravity, and
electrical forces are not required for simple diffusion.
2. In the Diffusion Gizmo, a student sets the temperature to 100 K and
records the time required for the system to reach dynamic equilibrium
(defined as when Region A contains between 45-55 particles out of 100
total). The student then repeats the experiment at 600 K, keeping all
,other variables constant. Based on kinetic molecular theory, what result
should the student expect?
A) Equilibrium will take longer at 600 K because higher temperature
causes particles to clump together
B) Equilibrium will be reached faster at 600 K because particles have
greater kinetic energy and move more rapidly
C) Temperature has no effect on diffusion rate because particle motion is
random at all temperatures
D) Equilibrium time will be identical because the concentration gradient,
not temperature, determines diffusion rate
Answer: B) Equilibrium will be reached faster at 600 K because particles
have greater kinetic energy and move more rapidly
Rationale: Temperature is directly proportional to average kinetic energy
(KE ∝ T). Higher kinetic energy means particles move faster, collide
more frequently, and cover distance more quickly, accelerating the rate
at which concentrations equalize. This is a fundamental principle
demonstrated in the Gizmo.
3. During a controlled experiment in the Diffusion Gizmo, a student
investigates how wall permeability affects diffusion rate. The student sets
up two trials: Trial 1 with the wall at 25% open (75% barrier) and Trial 2
with the wall at 85% open (15% barrier). All other variables
(temperature, particle mass, initial particle distribution) are identical.
Which prediction is scientifically accurate?
A) Trial 1 will reach equilibrium faster because the smaller opening
concentrates particle flow
B) Trial 2 will reach equilibrium faster because more particles can pass
through the larger opening per unit time
C) Wall permeability does not affect diffusion rate because particles will
eventually find any opening
D) Both trials will reach equilibrium at the same rate because
temperature is the only factor that matters
Answer: B) Trial 2 will reach equilibrium faster because more particles
can pass through the larger opening per unit time
,Rationale: The wall acts as a physical barrier to particle movement. A
higher percentage open means less obstruction, allowing more particles
to cross between regions simultaneously. This models how membrane
permeability affects diffusion in biological systems—greater permeability
= faster transport.
4. A student observes that in the Diffusion Gizmo, even after the system
reaches dynamic equilibrium (Region A ≈ 50 particles, Region B ≈ 50
particles), particles continue to move back and forth between regions.
Which statement BEST describes this observation?
A) The system has stopped functioning; particles should remain
stationary at equilibrium
B) Dynamic equilibrium means net movement is zero, but individual
particles continue random motion
C) Particles are actively pumping themselves to maintain equal
concentrations
D) The Gizmo simulation contains an error because equilibrium requires
all motion to cease
Answer: B) Dynamic equilibrium means net movement is zero, but
individual particles continue random motion
Rationale: "Dynamic" equilibrium emphasizes that particles never stop
moving (unless at absolute zero). At equilibrium, particles move equally
in both directions, so concentrations remain stable on average despite
continuous microscopic motion. This concept is critical for
understanding cellular homeostasis.
5. In the Diffusion Gizmo, a student changes the particle mass setting
from "light" to "heavy" while keeping temperature, wall permeability,
and initial concentrations constant. Based on the relationship between
mass, kinetic energy, and velocity (KE = ½mv²), what effect should the
student observe?
A) Heavy particles will diffuse faster because they have more momentum
B) Heavy particles will diffuse slower because, at equal kinetic energy,
velocity decreases as mass increases
C) Particle mass has no effect on diffusion rate because all particles move
at the same speed
D) Heavy particles will clump together, preventing diffusion entirely
, Answer: B) Heavy particles will diffuse slower because, at equal kinetic
energy, velocity decreases as mass increases
Rationale: At a given temperature, all particles have the same average
kinetic energy. Since KE = ½mv², if mass (m) increases, velocity (v)
must decrease to maintain constant KE. Slower-moving heavy particles
take longer to spread, explaining why small molecules (O₂) diffuse faster
than large ones (proteins) in biological systems.
6. A student using the Diffusion Gizmo records the number of particles
in Region A every 10 seconds and plots the data on a graph. The graph
shows a steep downward slope for the first 30 seconds, then gradually
flattens until reaching a horizontal line with small fluctuations. What
does the flattening of the curve indicate?
A) Particles have stopped moving entirely
B) The system is approaching dynamic equilibrium where net movement
approaches zero
C) The Gizmo simulation has crashed and is no longer recording data
D) Temperature has decreased, slowing particle motion
Answer: B) The system is approaching dynamic equilibrium where net
movement approaches zero
Rationale: The steep initial slope reflects rapid diffusion when the
concentration gradient is steepest. As concentrations equalize, the
gradient decreases, reducing net flow. The horizontal line with
fluctuations indicates dynamic equilibrium: particles still move, but no
further NET change occurs in concentration.
7. Which vocabulary term is BEST defined as "the net movement of
particles from an area of higher concentration to an area of lower
concentration due to random molecular motion"?
A) Osmosis
B) Active transport
C) Diffusion
D) Facilitated diffusion
Answer: C) Diffusion
EXPLORATION COMPLETE EXAM 151
to 200 2026 2027 CAPSTONE
SYNTHESIS AND ADVANCED
APPLICATIONS A+ VERIFIED
GIZMOS Student Exploration: Diffusion | Practice Exam
Questions [2026/2027]
1. A student opens the Diffusion Gizmo and observes gas particles
moving randomly in two connected chambers separated by a partial wall.
After 60 seconds, the student notices that particles have moved from
Region A (initially 100 particles) to Region B (initially 0 particles).
Which statement BEST explains why this movement occurred without
any external force applied?
A) Particles were actively transported by cellular energy (ATP) from high
to low concentration
B) Particles moved randomly due to kinetic energy, resulting in net
movement down the concentration gradient
C) Gravity pulled particles from Region A to Region B until
concentrations equalized
D) An electrical charge difference attracted particles from Region A to
Region B
Answer: B) Particles moved randomly due to kinetic energy, resulting in
net movement down the concentration gradient
Rationale: Diffusion is a passive process driven by the inherent kinetic
energy of particles. Random motion causes more particles to move from
high to low concentration simply due to probability, creating net
movement without external energy input. Active transport, gravity, and
electrical forces are not required for simple diffusion.
2. In the Diffusion Gizmo, a student sets the temperature to 100 K and
records the time required for the system to reach dynamic equilibrium
(defined as when Region A contains between 45-55 particles out of 100
total). The student then repeats the experiment at 600 K, keeping all
,other variables constant. Based on kinetic molecular theory, what result
should the student expect?
A) Equilibrium will take longer at 600 K because higher temperature
causes particles to clump together
B) Equilibrium will be reached faster at 600 K because particles have
greater kinetic energy and move more rapidly
C) Temperature has no effect on diffusion rate because particle motion is
random at all temperatures
D) Equilibrium time will be identical because the concentration gradient,
not temperature, determines diffusion rate
Answer: B) Equilibrium will be reached faster at 600 K because particles
have greater kinetic energy and move more rapidly
Rationale: Temperature is directly proportional to average kinetic energy
(KE ∝ T). Higher kinetic energy means particles move faster, collide
more frequently, and cover distance more quickly, accelerating the rate
at which concentrations equalize. This is a fundamental principle
demonstrated in the Gizmo.
3. During a controlled experiment in the Diffusion Gizmo, a student
investigates how wall permeability affects diffusion rate. The student sets
up two trials: Trial 1 with the wall at 25% open (75% barrier) and Trial 2
with the wall at 85% open (15% barrier). All other variables
(temperature, particle mass, initial particle distribution) are identical.
Which prediction is scientifically accurate?
A) Trial 1 will reach equilibrium faster because the smaller opening
concentrates particle flow
B) Trial 2 will reach equilibrium faster because more particles can pass
through the larger opening per unit time
C) Wall permeability does not affect diffusion rate because particles will
eventually find any opening
D) Both trials will reach equilibrium at the same rate because
temperature is the only factor that matters
Answer: B) Trial 2 will reach equilibrium faster because more particles
can pass through the larger opening per unit time
,Rationale: The wall acts as a physical barrier to particle movement. A
higher percentage open means less obstruction, allowing more particles
to cross between regions simultaneously. This models how membrane
permeability affects diffusion in biological systems—greater permeability
= faster transport.
4. A student observes that in the Diffusion Gizmo, even after the system
reaches dynamic equilibrium (Region A ≈ 50 particles, Region B ≈ 50
particles), particles continue to move back and forth between regions.
Which statement BEST describes this observation?
A) The system has stopped functioning; particles should remain
stationary at equilibrium
B) Dynamic equilibrium means net movement is zero, but individual
particles continue random motion
C) Particles are actively pumping themselves to maintain equal
concentrations
D) The Gizmo simulation contains an error because equilibrium requires
all motion to cease
Answer: B) Dynamic equilibrium means net movement is zero, but
individual particles continue random motion
Rationale: "Dynamic" equilibrium emphasizes that particles never stop
moving (unless at absolute zero). At equilibrium, particles move equally
in both directions, so concentrations remain stable on average despite
continuous microscopic motion. This concept is critical for
understanding cellular homeostasis.
5. In the Diffusion Gizmo, a student changes the particle mass setting
from "light" to "heavy" while keeping temperature, wall permeability,
and initial concentrations constant. Based on the relationship between
mass, kinetic energy, and velocity (KE = ½mv²), what effect should the
student observe?
A) Heavy particles will diffuse faster because they have more momentum
B) Heavy particles will diffuse slower because, at equal kinetic energy,
velocity decreases as mass increases
C) Particle mass has no effect on diffusion rate because all particles move
at the same speed
D) Heavy particles will clump together, preventing diffusion entirely
, Answer: B) Heavy particles will diffuse slower because, at equal kinetic
energy, velocity decreases as mass increases
Rationale: At a given temperature, all particles have the same average
kinetic energy. Since KE = ½mv², if mass (m) increases, velocity (v)
must decrease to maintain constant KE. Slower-moving heavy particles
take longer to spread, explaining why small molecules (O₂) diffuse faster
than large ones (proteins) in biological systems.
6. A student using the Diffusion Gizmo records the number of particles
in Region A every 10 seconds and plots the data on a graph. The graph
shows a steep downward slope for the first 30 seconds, then gradually
flattens until reaching a horizontal line with small fluctuations. What
does the flattening of the curve indicate?
A) Particles have stopped moving entirely
B) The system is approaching dynamic equilibrium where net movement
approaches zero
C) The Gizmo simulation has crashed and is no longer recording data
D) Temperature has decreased, slowing particle motion
Answer: B) The system is approaching dynamic equilibrium where net
movement approaches zero
Rationale: The steep initial slope reflects rapid diffusion when the
concentration gradient is steepest. As concentrations equalize, the
gradient decreases, reducing net flow. The horizontal line with
fluctuations indicates dynamic equilibrium: particles still move, but no
further NET change occurs in concentration.
7. Which vocabulary term is BEST defined as "the net movement of
particles from an area of higher concentration to an area of lower
concentration due to random molecular motion"?
A) Osmosis
B) Active transport
C) Diffusion
D) Facilitated diffusion
Answer: C) Diffusion
