Uploaded June 2025 | Updated September 2026, 2 weeks ago

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Ever wondered what makes toughened glass so tough? Watch as Hannah Fry puts some panes to the test and sees just how durable a fitness tracker is.

This clip is taken from the BBC series 'The Secret Genius of Modern Life' (2022). Watch the brand new series here: bbc.co.uk/programmes/m001f1tg

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