Medical research

Can humans sense the Earth's magnetism?

For migratory birds and sea turtles, the ability to sense the Earth's magnetic field is crucial to navigating the long-distance voyages these animals undertake during migration. Humans, however, are widely assumed not to ...

Ophthalmology

Your eyes are half a billion years old

Look after your eyes – they are at least half a billion years old, and a good deal older than your brain. The eyes are one of our most remarkable and precious organs, yet their origins have been shrouded in mystery until ...

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Sensor

A sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument. For example, a mercury thermometer converts the measured temperature into expansion and contraction of a liquid which can be read on a calibrated glass tube. A thermocouple converts temperature to an output voltage which can be read by a voltmeter. For accuracy, all sensors need to be calibrated against known standards.

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