It becomes half as large

It doubles

It quadruples

It remains unchanged

Molar mass

Density

Electrical permittivity (polarizability)

Thermal conductivity

Chemical energy is converted to mass energy

Electric potential energy is converted into thermal, light, and sound energy as charges move

Nuclear energy in air molecules is released as current flows

Magnetic energy becomes potential energy stored in the ground

It equals the external field

It is zero

It varies linearly with radius

It points opposite to the external field

Sudden fusion of air molecules into plasma due to high temperature and ionization

Slow rearrangement of neutral atoms aligning their magnetic moments

Movement of neutrons across the cloud–ground gap

Gradual diffusion of charged dust particles

They neutralize charges and reduce field strength

Collisions transfer charge, helping segregate positive and negative regions

Collisions create nuclear reactions that produce photons

They create sound waves that drive convection only

Both hold charge only at discrete points

Charge on the metal rod resides on the outer surface; charge on the insulator remains localized where placed

Both have uniform surface charge regardless of shape

Charge on the insulator sinks to its center while on the metal it is at the surface

Specific heat capacity

Electrical resistivity

Index of refraction

Malleability

Magnetic field lines force current to split

Air breakdown initiates along multiple weak points where local field exceeds breakdown threshold

Charge conservation requires branching to preserve total current

Branching indicates fusion events along the path

Low structures attract positive charges only

Buildings provide conductive paths and grounding, redistributing current away from occupants

Isolated structures prevent charge buildup so lightning prefers them

Inside a building, electrostatic forces are doubled

Magnetic flux density in tesla

Electric field magnitude in newtons per coulomb (or volts per meter)

Thermal gradient in °C/m

Optical brightness in lumens

Chemical → kinetic → nuclear

Electric potential → thermal → sound and light

Kinetic → electric potential → gravitational

Nuclear → thermal → electric potential

Thin wire (higher resistance per length)

Thick wire (lower resistance)

Both heat equally

Temperature rise depends only on current direction

Uniform charge distribution independent of cloud microphysics

Correlation between regions of strong updrafts, mixed-phase particles, and charge separation measurements

No relationship between particle collisions and measured electric fields

Constant cloud temperature despite charge separation

They remain fixed at their original locations

Charges redistribute until conductor is at uniform potential

All charge disappears into the conductor bulk

Only positive charges move while negatives stay

Induced opposite surface charge forms and some charge may flow to ground; internal field remains zero

Sphere’s net charge becomes equal to the cloud’s charge

Sphere’s internal field becomes nonzero and oscillatory

No change until a lightning strike occurs

Air composition, pressure, temperature, and gap distance (Paschen-like behavior)

Only its humidity

The color of the sky

Earth’s magnetic field strength

They are repelled due to induction of like charges

They are attracted because the induced opposite charges are closer than like charges, creating net attraction

They remain unaffected because they are neutral

They explode due to dielectric failure

Electrons accelerated in strong fields collide with atoms producing high-energy bremsstrahlung and photon emissions

Lightning converts protons into photons directly

Thermal emission at 300 K produces gamma rays

Magnetic reconnection in clouds releases gamma rays

Atomic number only

First ionization energy and electron configuration (valence electrons)

Atomic mass density

Noble gas affinity

They concentrate electric field lines producing higher local field strengths that ionize air

Sharps cool the air and prevent ionization

Rounded surfaces have higher field concentration

Corona occurs only at flat surfaces

Positive cloud-to-ground bolt originating from cloud top positive region

Negative cloud-to-ground bolt initiated from the negative region to ground

Intra-cloud lightning only between identical-charge regions

No lightning possible with opposite charges

Total measured positive charge plus negative charge remains constant before and after rubbing two objects

Only positive charge appears after rubbing

Net charge doubles spontaneously

Charge disappears into air

Leader is a cold neutral wind current

Leader advances in steps from cloud or ground, ionizing air and creating preferred path for return stroke

Leader forms due to gravitational attraction alone

Leader causes permanent magnetization along its path

Lightning only occurs above oceans

Leaders can propagate horizontally above cloud tops and then connect to ground far from rain, producing remote strikes

Thunderstorms project magnetic beams that attract lightning

Bolts from the blue are caused by auroras

Induced currents (electromagnetic induction) that can cause secondary damage or surges

Permanent magnetization of concrete

Complete shielding against subsequent strikes

Increased photosynthesis in plants

It will always go from ground to cloud

It will favor the path between regions of greatest potential difference, possibly producing complex multi-stroke strokes between cloud and ground

It will avoid the ground entirely

It always follows the shortest geometric route

Electric potential energy decreases; its sum is converted into thermal, light, and acoustic energy while satisfying conservation laws

Energy is created by the lightning channel

Energy disappears because of charge neutralization

Kinetic energy is the only product

Paint buildings white to reflect charge

Install a proper lightning protection system that provides a low-resistance path to ground and prevents side-flashes

Ensure all windows remain open during storms

Place isolated metal rods only at rooftop corners without grounding

Slow temperature rise over minutes

Bright optical emission, rapid expansion producing thunder (pressure wave)

Only ultraviolet light with no sound

Cooling of surrounding air

Creation of free electrons and ions (ionization) that carry current

Alignment of atomic nuclei to form chains

Increase in neutral particle density

Decrease of electron charge

Allow students to discharge capacitors into each other without supervision

Require signed safety contracts and ensure equipment and procedures minimize risk of sparks and burns

Use open flames to demonstrate ionization routinely

Encourage students to test conductive objects outdoors during storms

Only mass of larger object and temperature

Product of the two masses and inversely on the square of their separation distance

Sum of masses divided by distance

Only separation distance squared

A (more massive)

B (less massive)

Both have the same orbital period because period depends on central mass and radius, not the orbiting mass

Period depends on albedo, so indeterminate

$$T \propto r$$

$$T^2 \propto r^3$$

$$T \propto r^3$$

$$T^2 \propto r$$

Orbits are perfectly stable and never change

Perturbations from other bodies, collisions, and changes in eccentricity can alter orbits so paths cross Earth’s orbit at the same time and place

Gravity actively seeks collisions to equalize mass distribution

Orbits randomly teleport objects into Earth

Conservation of angular momentum only

Conversion between gravitational potential energy and kinetic energy: closer approach lowers potential energy, increasing kinetic energy

Gravitational energy is created at perihelion

Tidal heating increases speed

$$p = mv$$

$$E_k = \tfrac{1}{2} m v^2$$

$$E = mv$$

$$E_k = \tfrac{2m}{v}$$

Kepler’s laws assume no forces at all

Kepler’s laws assume a dominant central mass and neglect significant perturbations from other bodies (multi-body interactions)

They require objects to be charged

They only apply at quantum scales

It burned equally at all altitudes

It produced a bright bolide with high mass, survived fragmentation to ground as meteorites, and lacked strong volatile-driven outgassing signatures

It produced a persistent ion tail like a comet near perihelion

It moved in a straight line across the sky unaffected by gravity

Count and date crater populations on lunar surfaces of different ages and infer rates

Measure current lunar magnetic field only

Observe lunar weather patterns

Survey present lunar atmosphere composition

Kinetic impactor alters velocity by momentum transfer in a short impulsive event; gravity tractor slowly changes orbit using mutual gravitational attraction over time

Both rely on nuclear detonation to vaporize the asteroid

Gravity tractor collides physically and bounces off the asteroid

Kinetic impactor uses magnetic fields only

Color of asteroid

Kinetic energy (roughly proportional to and angle of impact and target properties)

Asteroid’s electric charge alone

Time of day of impact

Earth’s atmosphere permanently protects it from all impacts

Geological processes (erosion, plate tectonics, volcanism) and sedimentation erase or obscure craters over time

Earth never experienced heavy bombardment

Moon’s craters are formed by erosion only

It will immediately fall into the central body

It will move to a higher-energy elliptical orbit with greater apocenter, possibly escape if speed exceeds escape velocity

It will stop moving

It will transmute into plasma

Localized crater with no global deposits

Global layer enriched in iridium and shocked minerals, climatic proxies indicating abrupt changes in sunlight and temperature aligning with extinction events

Increase in lunar craters at same time

No change in fossil records

$$F = G\frac{M+m}{r}$$

$$F = G\frac{Mm}{r^2}$$

$$F = G\frac{M - m}{r^3}$$

$$F = \frac{GM}{r}$$

Sign and magnitude of total orbital energy (kinetic + potential); negative total energy indicates a bound orbit (elliptical), zero parabolic, positive hyperbolic (unbound)

Color of the object

The number of moons the object has

The object’s density only

Steeper angles increase atmospheric deceleration and heating efficiency, making ground impact more likely for larger objects; shallow angles increase path length and can cause the object to skip or fragment

Angle has no effect; only mass matters

Shallow angles always guarantee ground impact

Angle determines only the color of the meteor

Fragmentation increases surface area; increased atmospheric drag and ablation reduce terminal mass reaching the surface

Fragmentation creates more focused energy at ground

Fragmentation increases gravitational pull toward Earth

Fragmentation generates vacuum pockets that amplify impact

Speed is constant around the ellipse

Speed varies: fastest at periapsis (closest point), slowest at apoapsis (furthest point)

Speed depends only on mass of the orbiting body

Elliptical orbits violate energy conservation

Its spectral color only

Its orbit parameters (semi-major axis, eccentricity, inclination), size estimate (mass), and current position/velocity to project future close approaches

The brightness of its reflected radio signals

The local weather where discovered

It halves the force

It reduces the force to one-fourth

It leaves the force unchanged

It increases the force fourfold

Abundant fresh large craters everywhere on Earth

Observations of meteor showers, recovered micrometeorites, and statistical frequency showing most small-mass objects ablate in the atmosphere

Complete lack of meteorites in museum collections

Constant mass gain of Earth's atmosphere each year

Spacecraft gains kinetic energy relative to the Sun by exchanging momentum with the planet (planet loses an imperceptible amount)

Spacecraft’s mass increases to conserve energy

Planet gains significant velocity and moves noticeably

Gravity assist violates conservation of energy

Continuous solar radiation pressure only

Close gravitational encounters with planets or collisions with other bodies that perturb orbital shape

Its color and reflectivity only

Internal heating alone

Numerical rounding only

Small perturbations from many bodies, non-gravitational forces (e.g., outgassing), and sensitivity to initial conditions (chaotic behavior)

The phase of the Moon only

Earth’s magnetic field variations

Total mechanical energy and angular momentum (each conserved)

Temperature only

Chemical composition only

Orbital eccentricity always remains fixed

Rapid volatile heating and mechanical failure caused fragmentation and sudden energy release

It passed untouched through the atmosphere

It gained mass mid-flight

It transformed into liquid water

T halves

T decreases by a factor of $$\sqrt{2}$$

T doubles

T is unchanged

Cometary debris (dust and small particles) left along the comet’s orbit intersects Earth’s path and ablates in the atmosphere producing visible meteors

Comets emit sound that creates meteors

Meteor showers are only caused by asteroids

Meteor showers occur due to volcanic ash in the atmosphere

Single small ground telescope

Systematic sky surveys combining wide-field optical and infrared telescopes, repeated observations, and orbit determination to accumulate long observation arcs

Waiting for accidental sightings by the public

Only using radio waves pointed at the Sun

It is gravitationally bound and will return periodically

It is unbound and will escape the solar system after close approach (positive total energy)

It will settle into a circular orbit soon

It must be man-made

Increased sunlight reaching the surface immediately

Short-term cooling (reduced solar insolation), disruptions to photosynthesis, and longer-term ecological impacts depending on magnitude and duration

Immediate warming only

No climatic effect

Cellular respiration

Photosynthesis

Combustion

Weathering

Drought decreases solar radiation

Drought dries vegetation, increasing fuel flammability and likelihood of ignition and rapid spread

Drought increases soil oxygen content preventing fires

Drought causes plants to produce fireproof chemicals

Peat contains stored carbon and can burn slowly at low oxygen and low temperatures, insulated by snow and organic layers

Ice chemically ignites peat making it hotter

Snow provides extra oxygen to fuel combustion

Zombie fires are a myth with no physical basis

Photosynthesis releases carbon dioxide; respiration stores it

Photosynthesis converts CO₂ and water into organic carbon and stores energy; respiration breaks down organics releasing CO₂ and energy

Both are identical processes with different names

Only respiration requires sunlight

Permafrost decomposition is faster due to higher temperatures

Permafrost decomposition is slower because cold temperatures and low oxygen slow microbial activity, trapping carbon longer

Permafrost decomposes only via fire

Permafrost decomposition produces only methane, never CO₂

Negative feedback that stabilizes climate

Positive feedback: CO₂ causes warming, droughts increase, fires become more frequent/intense, releasing more CO₂

No feedback exists between CO₂ and fires

CO₂ directly decreases fire likelihood

Vary projectile color while holding mass and speed constant

Vary impact speed while keeping mass constant to observe relationship between speed and crater diameter

Change flour brand only

Vary room humidity only

Reforestation programs

Burning fossil fuels and deforestation that release geologic and biomass carbon reservoirs

Planting cover crops

Reducing livestock numbers

More species always reduce photosynthesis

Diverse species provide functional redundancy and resilience, aiding recovery of matter and energy flows

Biodiversity prevents any regrowth

Biodiversity increases soil temperatures to harmful levels

Rapid aerobic decomposition

Slow accumulation under waterlogged, low-oxygen conditions that inhibit decomposition, preserving organic carbon for long periods

Peat converts carbon into inert noble gases

Peat reflects sunlight preventing photosynthesis