explainer · HACKER NEWS RECOMMENDATION
Why does light slow down in water?
Fermilab · 3 HN recommenders · 3 recommendation months
Recommended by 3 Hacker News commenters across 3 months (2020–2023).
SignalTube analysis
Among 81 other explainer videos tagged Fundamental physics, the mean is 2.7 distinct HN recommenders. This video has 3 distinct HN recommenders, close to that mean. Recommendations span 3 distinct months; the peer average is 2.4 months. This is a data-derived comparison, not a human review or quality rating.
75% of its 4 labeled comments are marked as recommendations or strong recommendations. HN mention years are 2020–2023; those years describe discussion history, not upload date. Its verified runtime is 10 minutes 24 seconds. YouTube lists its publication date as 2019-02-20.
- Channel / speaker
- Fermilab
- Verified runtime
- 10m 24s
- YouTube upload date
- 2019-02-20
- Hacker News mention years
- 2020–2023
SAME TOPIC AND FORMAT
Compare with related videos
The comparison cohort uses other explainer videos in Fundamental physics. “Shared recommenders” counts HN users who recommended both videos in the source graph.
| Video | HN recommenders | Recommendation months | Positive label share | Shared recommenders | Runtime | Upload date |
|---|---|---|---|---|---|---|
| Why does light slow down in water?Current video | 3 | 3 | 75% | — | 10m 24s | 2019-02-20 |
| The Speed of Light is NOT About Lightexplainer · PBS Space Time | 8 | 8 | 67% | No recorded overlap | 12m 46s | 2015-10-07 |
| A new way to visualize General Relativityexplainer · ScienceClic English | 8 | 6 | 89% | No recorded overlap | 11m 33s | 2020-09-03 |
| How to Understand What Black Holes Look Likeexplainer · Veritasium | 8 | 4 | 80% | No recorded overlap | 9m 19s | 2019-04-09 |
THREE SOURCE-BASED CONTEXT POINTS
Why Hacker News recommends it
Each note combines the dataset’s stance label and short rationale; comment bodies are not reproduced. Open the HN source for the original discussion.
The archive classifies this as a recommendation in “What is a zero refractive index material?”. Its short rationale: Fermilab videos on refractive index.
The archive classifies this as a recommendation in “Ask HN: Concepts that clicked only years after you first encountered them?”. Its short rationale: Why light is slower in media with higher refractive index.
The archive classifies this as a contextual reference in “Well, Actually – Physics Answers”. Its short rationale: Source refuting the absorb and re-emit explanation.