Density Required Practical, Accuracy and Precision (Two Dense Objects)

Photograph: Jane Ni (see below for link)


Thomas and Robin chat about another required practical in UK GCSEs, measuring the density of regular and irregular objects. They run down the rabbit hole of accuracy vs precision before chatting about crazy ways of measuring everyday values.

Photograph: NSO/AURA/NSF

Physics in the news this week is the recent close up photograph of the surface of the Sun, or “golden nuggets” as Thomas called it. Each pixel is 30km, meaning that if this were the whole sun the photo would be metres across.

The next topic is the everyday required practical in the UK of measuring density. What are the pitfalls? Who doesn’t love a Eureka can? It turns out that Robin is not a fan, and Thomas finds them a tricky proposition too.

A quick foray in to Accuracy vs Precision where Thomas reminisces about WWI (he’s not that old) and tells a story from his past to illustrate the difference.

The final part of the podcast has Thomas telling Robin about how he measured the diameter of ball bearings by dropping them in glycerol as an analogue for the Millikan experiment.


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The music we use remains One legged equilibrist polka by Circus Homunculus. Occasionally we also use Cantina Rag by Jackson F. Smith.

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