Why the kilogram was redefined: the end of the metal cylinder
For 130 years the kilogram was a platinum-iridium cylinder in a Paris vault, but measurable drift against its own copies forced…
Amelia Hart
Amelia Hart
Technology Correspondent
Amelia Hart covers artificial intelligence, consumer tech and the platform economy. She has written about the technology industry for more than a decade.
What happens when you delete a file and why it is rarely gone
Deleting a file usually removes only the directory entry pointing to it, leaving the data on disk until overwritten, which makes recovery…
Amelia Hart
Why so much carefully sorted recycling never gets recycled
Contamination, mixed materials and weak end markets mean a share of household recycling is rejected or downgraded, and the fixes sit mostly…
Amelia Hart
Apprenticeship or university: the comparison worth making properly
Degree apprenticeships pay a wage and charge no fees, but places are scarce and employer-dependent, which changes how the choice should be…
Amelia Hart
How GCSE grades are actually decided behind the number scale
GCSE grade boundaries move every year by design, because the system holds the meaning of a grade steady rather than the marks needed to…
Amelia Hart
Heat pumps in older homes: separating experience from folklore
Field trials show heat pumps working in most UK housing, including older stock, but success depends on system design and radiator sizing…
Amelia Hart
How carbon dating actually works and what it cannot tell you
Radiocarbon dating measures the decay of carbon-14 in once-living material, but calibration curves, contamination and a ceiling near 50,000…
Amelia Hart
How contactless payments actually work
A contactless tap runs a full EMV cryptographic exchange over NFC in under half a second, and the £100 limit exists because of liability…
Amelia Hart
EU Meta addictive-design finding puts Facebook and Instagram under pressure
The European Commission's preliminary Digital Services Act finding targets design features such as infinite scroll, autoplay, push alerts…
Amelia Hart