Photogates do not determine the sign of velocity, cannot show zero velocity with non-zero acceleration at the turning point, and afford the Δv/Δx rather than the Δv/Δt definition of acceleration¶
Claim · All claims
Evidence · 1 study · qualitativer2·q1
Currency · newest study 2018 · not yet checked against its sources · not reviewed by a person · overdue for a recheck since 2021: tool and model accuracy changes quickly
Subclaims¶
Reading the evidence codes
q is the design tier, i the impact, n the sample, and the kind with its r
the rigour judged within that kind: what each code means.
This claim: no standardized effect is recorded in observations/ for it yet, so no benchmark reading is possible.
q1 i? In the photogate lab, only speed and not the sign of velocity is directly determined, the equipment cannot provide data showing zero velocity but non-zero acceleration at the turning point, and Δv/Δx is afforded while Δv/Δt is not. → Jonte Bernhard 2018
Evidence¶
Jonte Bernhard 2018¶
Jonte Bernhard. (2018). What matters for students' learning in the laboratory? Do not neglect the role of experimental equipment! Instructional Science. https://doi.org/10.1007/s11251-018-9469-x
q1 · i? · qualitative · r2
Affordance analysis of the photogate lab (glider on an air track with two photogates), showing only speed is directly determined so "there is a risk that students make a sign mistake". The article adds that the equipment cannot show zero velocity with non-zero acceleration at the turning point and that the "wrong" definition of acceleration (Δv/Δx) is afforded, but not the "right" one.
"since only speed—and not the sign of the velocity—is directly determined using the experimental equipment, there is a risk that students make a sign mistake when asked to perform this task."
Discussion¶
Related Claims¶
- Students' courses of action differed by instrumentation: photogate and tape-timer groups centred on numbers and dots with motion concepts rare, while probeware groups centred on motion concepts — related
- Probeware affords measurement of acceleration at the cart's highest point after an upward push, permitting the fallacy that acceleration is zero there to be addressed — reports the opposite
- What is possible for students to perceive or discern in a laboratory depends on the measurement technology used, even when the object of learning is the same — a broader claim this one bears on
- The tape timer affords study of downward motion only, so the direction of acceleration and the acceleration at the turning point cannot be addressed — related
Page metadata
| Field | Value |
|---|---|
type |
claim |
id |
photogates-affordance-limits-inclined-plane |
title |
Photogates do not determine the sign of velocity, cannot show zero velocity with non-zero acceleration at the turning point, and afford the Δv/Δx rather than the Δv/Δt definition of acceleration |
description |
Photogates do not determine the sign of velocity, cannot show zero velocity with non-zero acceleration at the turning point, and afford the Δv/Δx rather than the Δv/Δt definition of acceleration |
status |
review |
evidence_strength |
moderate |
newest_evidence |
2018 |
recheck_by |
2021 |
generated |
by process:wiki-ingest on 2026-10-18 |
trust |
unverified — no one has confirmed this page's content |
sources |
1 — jonte-bernhard-2018 |
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