AP Physics 1 Lab Investigations16 Suggested Inquiry Investigations

The 16 suggested AP Physics 1 lab investigations

1. 1

   Acceleration Due to Gravity and Kinematics

   BI4: Change

   Students design an experiment to measure the acceleration due to gravity using free fall or projectile techniques, often employing a motion sensor, spark timer, or video analysis to collect time and displacement data. The investigation asks students to define the independent and dependent variables explicitly, control for experimental error, and derive g from a linearized graph such as displacement versus time squared. Method overview includes dropping objects, measuring intervals, and constructing a best fit line whose slope yields the acceleration. Key concepts are uniform acceleration, the kinematic equations, graphical linearization, and percent error analysis. Students must also evaluate systematic errors such as air resistance and timing precision, and justify why their measured value differs from the accepted 9.8 meters per second squared. The investigation develops Science Practice 5 (Data Analysis) centrally, with Science Practice 4 (Experimental Methods) governing the procedure design.

   On the exam: Appears in kinematics based Experimental Design FRQs asking students to identify variables, describe a measurement procedure, and sketch a displacement versus time squared graph with labeled axes.

2. 2

   Newton's Second Law (Net Force and Acceleration)

   BI3: Force Interactions

   Students use an Atwood machine, a dynamics cart on a track with a hanging mass, or a force probe to vary net force while holding mass constant (and vice versa), measuring acceleration with a motion detector. The central question is how acceleration depends on net force and on total system mass. Students draw a free body diagram for the system, derive a theoretical prediction for acceleration using Newton's second law, then compare the predicted and measured values. Graphing acceleration versus net force yields a linear relationship whose slope is the inverse of system mass; graphing acceleration versus inverse mass yields a line through the origin. Key concepts are Newton's second law in vector form, internal versus external forces in a system, friction as a systematic error, and the distinction between the force applied to an object and the net force on the system. This investigation is among the highest transfer value labs for the exam.

   On the exam: Directly supports Newton's second law FRQ scenarios asking students to design an experiment to determine how acceleration depends on net force or mass, including predicting the shape and slope of the expected graph.

3. 3

   Forces in Equilibrium and Static Systems

   BI3: Force Interactions

   Students construct a static system such as a hanging sign supported by two cables at different angles, use a force table or spring scales, and verify that the vector sum of all forces equals zero when the object is in equilibrium. The investigation requires resolving forces into horizontal and vertical components, building a free body diagram, and using trigonometry to compute predicted force magnitudes for comparison with measured values. Key concepts are the conditions for translational equilibrium, vector addition of forces, the role of the normal force, and the effect of changing cable angles on tension magnitude. Students must identify why measured and predicted tensions differ (scale calibration, friction at the node, string mass) and evaluate whether discrepancies are within reasonable experimental uncertainty. Science Practice 1 (Modeling) is central because the free body diagram is both the analytical tool and the graded deliverable on related FRQ questions.

   On the exam: Supports FRQ questions that provide a diagram of a hanging or supported object and ask students to draw a correct free body diagram and justify force magnitude relationships.

4. 4

   Projectile Motion

   BI4: Change

   Students launch a projectile horizontally from a known height or at a known angle using a spring loaded launcher, measure the landing position, and compare the measured range to the theoretical prediction derived from kinematics equations applied independently to horizontal and vertical components. The investigation makes the independence of horizontal and vertical motion experimentally concrete: horizontal velocity is constant while vertical acceleration is uniform at g. Students vary launch height or angle, construct a graph of range versus the predicted variable, and assess how well the slope of the best fit line matches the theoretical prediction. Key concepts are the separation of two dimensional motion into perpendicular components, time of flight as the linking variable, and sources of experimental error such as air resistance, launcher inconsistency, and measurement of the landing position. The investigation connects directly to the kinematics unit and extends to circular motion reasoning.

   On the exam: Appears in Quantitative Qualitative Translation FRQs and short answer questions asking students to predict how the landing range changes when launch height or speed is altered, using kinematic reasoning.

5. 5

   Circular Motion and Centripetal Force

   BI3: Force Interactions

   Students whirl a rubber stopper or similar object on a string through a tube, holding radius constant while varying hanging mass (which sets the centripetal force), and measure period by timing multiple revolutions. Alternatively, a centripetal force apparatus on a rotating platform is used. Students graph centripetal force versus the square of the frequency, verify the linear relationship predicted by the equation F equals m times four pi squared times r divided by T squared, and evaluate whether the measured centripetal force matches the weight of the hanging mass. Key concepts are centripetal acceleration as directed toward the center, centripetal force as the net inward force provided by identifiable real forces (tension here, gravity in orbit), the inverse relationship between period and frequency, and the distinction between centripetal force and the centrifugal sensation. The most common misconception addressed is treating centripetal force as a separate applied force rather than the net result of existing forces.

   On the exam: Supports circular motion FRQs asking students to identify the force providing centripetal acceleration in different contexts and to predict how period changes when radius or speed is altered.

6. 6

   Conservation of Energy (Ramp or Spring Systems)

   BI5: Conservation Laws

   Students release a cart down a ramp or a mass on a spring and track how gravitational or elastic potential energy converts to kinetic energy, using motion sensors and force probes to record velocity and position. An energy bar chart is constructed at multiple points to verify conservation of mechanical energy. Students calculate gravitational potential energy from measured height, kinetic energy from measured velocity, and elastic potential energy from spring compression, then account for the energy budget at each position. Key concepts are the work energy theorem, the conditions under which mechanical energy is conserved versus lost to friction, the definition of the system including or excluding the Earth, and power as the rate of energy transfer. The most testable skill is constructing and interpreting an energy bar chart, which the AP Physics 1 exam tests directly as a modeling task requiring Science Practice 1.

   On the exam: Directly supports energy FRQs that provide a scenario and ask students to construct an energy bar chart, apply the work energy theorem, or predict how friction changes the final speed.

7. 7

   Conservation of Momentum (Collision Carts)

   BI5: Conservation Laws

   Students use dynamics carts with magnetic or Velcro bumpers to produce elastic and perfectly inelastic collisions on a low friction track, measuring cart velocities before and after collision with motion detectors. Total momentum and total kinetic energy are calculated before and after each collision type, and the results are compared to verify that momentum is conserved in both cases while kinetic energy is conserved only in the elastic case. Students must justify which quantity is conserved and why: momentum conservation follows from Newton's third law and the absence of external horizontal forces; kinetic energy loss in an inelastic collision converts to internal energy. Key concepts are the definition of a closed system for momentum purposes, the difference between elastic and inelastic collisions, the distinction between momentum and kinetic energy as conserved quantities, and the sources of experimental uncertainty such as track tilt and friction. This investigation is a direct analog of the Quantitative Qualitative Translation FRQ scenario type.

   On the exam: Directly maps to FRQ questions presenting a two cart collision scenario and asking students to apply conservation of momentum, compare kinetic energies, or predict post collision velocities for a modified scenario.

8. 8

   Impulse and the Impulse Momentum Theorem

   BI5: Conservation Laws

   Students use a force probe and motion sensor to measure the force versus time profile of a collision (cart striking a bumper) and verify that the area under the force time curve equals the change in momentum. By changing collision duration using a hard or soft bumper, students observe that a longer collision time reduces peak force for the same impulse, connecting the investigation to airbags and padding. Key concepts are the impulse as the product of average force and time interval, the impulse momentum theorem as a vector equation, the area under a force time graph as the impulse, and the inverse relationship between collision duration and peak force at constant impulse. The graphical integration skill (estimating area under a curve) transfers directly to data analysis FRQ tasks. Students distinguish impulse as a change in momentum from momentum as a quantity of motion.

   On the exam: Supports short answer and Experimental Design FRQ questions asking students to interpret a force time graph, calculate impulse from the area, and predict how changing collision duration affects peak force.

9. 9

   Simple Harmonic Motion (Spring Mass or Pendulum)

   BI4: Change

   Students measure the period of oscillation of a spring mass system and a simple pendulum while systematically varying mass, spring constant, pendulum length, and amplitude to determine which variables affect the period. The investigation makes the contrast between the two systems concrete: for a spring mass system the period depends on mass and spring constant but not amplitude; for a pendulum the period depends on length and gravitational field strength but not mass or amplitude (for small angles). Students use a stopwatch or photogate, average over many oscillations to reduce timing uncertainty, and construct graphs of period squared versus mass (spring) and period squared versus length (pendulum) to derive the proportionality constants. Key concepts are the restoring force condition for SHM, the equations for period of each system, the energy oscillation between kinetic and potential, and the conditions under which the small angle approximation is valid.

   On the exam: Appears in FRQ questions asking students to predict how the period of a spring mass or pendulum system changes when a variable is altered, and to justify the prediction using the relevant period equation.

10. 10

    Torque and Rotational Equilibrium

    BI3: Force Interactions

    Students use a meter stick balanced on a pivot with hanging masses at measured positions to verify the torque condition for rotational equilibrium: the sum of clockwise torques equals the sum of counterclockwise torques. By varying mass and distance, students confirm that torque is the product of force and perpendicular distance from the pivot, not force alone. The investigation builds the rotational free body diagram, which carries the same rubric weight as the translational free body diagram on related FRQs. Key concepts are torque as a quantity requiring both force magnitude and moment arm, the conditions for translational and rotational equilibrium simultaneously, why the choice of pivot point does not change whether equilibrium holds, and the qualitative effect of shifting a mass closer to or farther from the pivot on the balance of the system.

    On the exam: Supports Experimental Design and short answer FRQs presenting a lever or beam scenario and asking students to draw a rotational free body diagram, calculate torques, or predict how balance changes when a mass is repositioned.

11. 11

    Conservation of Angular Momentum (Rotating Platform)

    BI5: Conservation Laws

    Students use a rotating platform or a stool with extendable arms to observe that pulling mass inward increases rotational speed while extending mass outward decreases it, consistent with conservation of angular momentum when no net external torque acts. Quantitatively, students measure moment of inertia configurations and angular velocity to verify that their product is conserved. Key concepts are angular momentum as the product of moment of inertia and angular velocity, the no external torque condition for conservation, the inverse relationship between moment of inertia and angular velocity at constant angular momentum, and real world examples including ice skaters and divers. The Making Connections Science Practice is central: students map the rotational conservation law onto their prior knowledge of linear momentum conservation, identifying the structural parallel between the two conservation principles.

    On the exam: Appears in Quantitative Qualitative Translation FRQs asking students to predict the direction and magnitude of a change in angular velocity when moment of inertia changes, and to justify using conservation of angular momentum.

12. 12

    Coulomb's Law and Electric Force

    BI2: Fields

    Students use charged spheres, a torsion balance, or a Coulomb's Law apparatus to measure the force between two charges at varying distances and with varying charge magnitudes, verifying the inverse square dependence on distance and the linear dependence on each charge. Graphing force versus the inverse square of distance yields a line whose slope estimates Coulomb's constant k. Key concepts are Coulomb's Law as the electrostatic analog of Newton's Law of Universal Gravitation, the superposition principle for multiple charges, the difference between electric force and electric field, and the role of charge sign in determining attraction or repulsion. The practical challenge of preventing charge leakage introduces conductors versus insulators. The connection to Newton's gravitational law reinforces Making Connections and highlights the structural parallel between the two inverse square laws treated in AP Physics 1.

    On the exam: Supports FRQ questions presenting a charged particle scenario and asking students to predict force magnitude or direction when charge or separation changes, using Coulomb's Law and the superposition principle.

13. 13

    DC Circuits and Ohm's Law

    BI5: Conservation Laws

    Students build series and parallel resistor circuits, measure voltage across and current through each element with a multimeter, and verify Ohm's Law (V equals IR) for individual resistors. They then test Kirchhoff's voltage rule (the loop rule, that the sum of potential differences around any closed loop is zero) and Kirchhoff's current rule (the junction rule, that the current entering a junction equals the current leaving). The investigation makes circuit diagrams into predictive tools: students draw the circuit schematic, predict voltages and currents algebraically, then compare predictions to measurements. Key concepts are resistance, voltage, and current as distinct quantities, the rules for combining resistors in series and parallel, power dissipation in each element, and why adding a branch to a parallel circuit decreases total resistance and increases total current drawn from the source. Students also learn to use the multimeter correctly, including understanding that an ammeter must be placed in series and a voltmeter in parallel.

    On the exam: Appears in DC circuits FRQ scenarios asking students to predict how adding or removing a branch changes voltage and current throughout the circuit, and to justify using Kirchhoff's rules or equivalent resistance reasoning.

14. 14

    Kirchhoff's Voltage Rule Verification

    BI5: Conservation Laws

    Students construct a multi loop circuit with known resistors and a battery, measure voltage drops across each element, and verify that the algebraic sum of voltage changes around any closed loop equals zero. The investigation separates Kirchhoff's voltage rule from Ohm's Law: the loop rule holds as a consequence of energy conservation even when individual resistances are unknown. Students identify two or more independent loops, write the loop equations, solve for unknown currents, and compare predictions with measurements. Key concepts are potential difference as energy per charge, the battery as a source that raises potential while resistors dissipate it, the sign convention for voltage changes around a loop, and why the loop rule is a statement of energy conservation. Students also examine internal resistance and how it lowers terminal voltage relative to the battery EMF.

    On the exam: Supports circuit FRQ questions where students must apply Kirchhoff's rules to a multi loop circuit diagram to find current or voltage in a specified branch, and justify why the rule applies using energy conservation reasoning.

15. 15

    Mechanical Waves and Standing Waves on a String

    BI6: Waves

    Students drive a string with a mechanical oscillator at one end, adjust frequency to find resonant standing wave modes, and measure wavelength from the node spacing for each harmonic. By varying string tension using hanging masses and string linear density (different string thicknesses), students derive the wave speed equation: v equals the square root of tension divided by linear density. Students graph wave speed squared versus tension to verify the linear relationship and extract the linear density from the slope. Key concepts are the superposition principle as the origin of standing waves, nodes and antinodes as points of destructive and constructive superposition respectively, the harmonic series (the nth harmonic has n antinodes), the relationship between wave speed, frequency, and wavelength, and how changing tension or linear density changes wave speed without changing frequency (which is set by the oscillator). The investigation builds the quantitative intuition for wave speed that underlies all wave unit exam questions.

    On the exam: Appears in Experimental Design and Quantitative Qualitative Translation FRQs asking students to predict how changing string tension or linear density affects wave speed, wavelength, or the frequency required to produce a specific harmonic.

16. 16

    Sound and Resonance in Air Columns

    BI6: Waves

    Students use a resonance tube (a tube partially submerged in water) and a tuning fork of known frequency to find the column lengths at which resonance occurs, then use the node antinode spacing to determine the wavelength of sound and calculate the speed of sound in air. Testing multiple tuning fork frequencies confirms that wave speed in air is approximately constant while wavelength varies inversely with frequency. A temperature correction is applied to compare the measured speed with the theoretical value (approximately 331 plus 0.6 times the Celsius temperature in meters per second). Key concepts are the resonance conditions for open versus closed tubes, the standing wave pattern in each case (closed end is a displacement node, open end is a displacement antinode), the harmonic series for each tube type, and the Doppler effect as a frequency shift produced by relative motion between source and observer.

    On the exam: Supports wave unit FRQ questions asking students to predict the resonant length for a given frequency in an open or closed tube, explain the Doppler effect qualitatively, or compare wave speeds in different media.

The 16 investigations above are College Board's suggested investigations from the AP Physics 1 Investigative Lab Manual. They are explicit guidance, not a fixed required list. The AP Physics 1 course framework requires that students conduct inquiry based investigations across the course's 10 units that collectively develop all 7 Science Practices. Teachers design or select investigations within this framework; the College Board lab manual provides these 16 as representative examples aligned to the Big Ideas and units.