All objects fall at the same rate on Earth regardless of their mass.

Is it true that all objects fall at the same rate on Earth regardless of their mass?

Partly. Several sources support equal fall rates only in ideal conditions: a small drop experiment found equal acceleration for five objects, a physics derivation gives a = g for all masses absent air resistance, and the MICROSCOPE mission states the weak equivalence principle for two orbiting test masses. One peer-reviewed paper argues the belief that all objects fall at the same rate is a naive bias because air resistance is ignored, so the evidence covers only part of the claim and points both ways.

Verdict: CONTESTED PARTIAL · 4 sources for, 1 against · Last checked 2 Oct 2026

The private library was unavailable for some searches in this check. Missing library results are not evidence against the claim.

Hallur, A., Chan, J., Reznik, M., Zlotnikov, P., & Tiboni, J. (2026). Objects fall with constant acceleration regardless of mass. doi.org. https://doi.org/10.64804/hsepny74

D., O. C., K., M. M., C., M. S., & G., S. T. (2005). The Galileo Bias: A Naive Conceptual Belief That Influences People's Perceptions and Performance in a Ball-Dropping Task. eric.ed.gov. https://eric.ed.gov/?id=EJ734693

Why do two bodies of different masses fall at the same rate.... (n.d.). physics.stackexchange.com. https://physics.stackexchange.com/questions/11321/why-do-two-bodies-of-different-masses-fall-at-the-same-rate-in-the-absence-of-a

Gravity String Theory: A Phenomenological Model of Two-Way Attraction. (2025). doi.org. https://doi.org/10.5281/zenodo.17022135

MICROSCOPE. mission analysis, requirements and expected performance. (n.d.). cir.nii.ac.jp. https://doi.org/10.1088/1361-6382/abebf1