But Why Would Light 'Slow Down'? Visualizing Feynman's Lecture on the Refractive Index
Published 30 Nov 2023 · 25 daily observations recorded · last updated 2026-09-29
Recent growth
Performance history
Every observation TubeSum recorded, plotted as measured.
Based on 25 observations · last observed Sep 29, 2026 · straight lines connect consecutive observations — TubeSum does not measure the days between them.
All observations
The same points the chart plots, as exact numbers. Gaps mean no observation was taken that day.
| Date | Views | Avg views / hour | Channel median |
|---|---|---|---|
| 2026-09-29 | 2,864,688 | 115.5 | — |
| 2026-09-28 | 2,863,595 | 115.6 | — |
| 2026-09-27 | 2,862,640 | 115.6 | — |
| 2026-09-26 | 2,861,365 | 115.7 | — |
| 2026-09-25 | 2,860,085 | 115.8 | — |
| 2026-09-24 | 2,859,123 | 115.8 | — |
| 2026-09-23 | 2,858,192 | 115.9 | — |
| 2026-09-22 | 2,857,369 | 116.0 | — |
| 2026-09-21 | 2,856,786 | 116.0 | — |
| 2026-09-20 | 2,855,971 | 116.2 | — |
| 2026-09-19 | 2,855,259 | 116.2 | — |
| 2026-09-18 | 2,854,743 | 116.3 | — |
| 2026-09-17 | 2,853,964 | 116.4 | — |
| 2026-09-16 | 2,852,709 | 116.5 | — |
| 2026-09-15 | 2,852,074 | 116.6 | — |
| 2026-09-14 | 2,851,245 | 116.6 | — |
| 2026-09-13 | 2,850,389 | 116.7 | — |
| 2026-09-12 | 2,849,840 | 116.8 | — |
| 2026-09-11 | 2,849,003 | 116.9 | — |
| 2026-09-07 | 2,845,818 | 117.2 | — |
| 2026-09-04 | 2,843,346 | 117.5 | — |
| 2026-09-01 | 2,840,800 | 117.7 | — |
| 2026-08-27 | 2,836,770 | 118.1 | — |
| 2026-08-17 | 2,832,919 | 119.2 | 1,262,848 |
| 2026-08-10 | 2,830,364 | 119.9 | 1,262,848 |
Content analysis
Transcript, chapters and structure for this video live on its analysis page — performance and content are separate documents on TubeSum.
Read transcript & analysis →