Carlo Ratti

Like a tracer running through the veins of the city, networks of air quality sensors attached to bikes can help measure an individual's exposure to pollution and draw a dynamic map of the urban air on a human scale, as in the case of the Copenhagen Wheel developed by new startup Superpedestrian.

Italian Architect

Used in scientific and medical contexts to describe how something is followed or monitored over time.

Tracking Usage

'Tracer' in this context often refers to abstract tracking methods, like a signal, not a physical object.

Not Physical

Military tracers are used to see where shots land at night or in low-visibility conditions.

Visibility in Dark

Using tracer rounds can give away a shooter's position to the enemy, as they can see the tracers too.

Reveal Position

As a figure of speech, 'tracer' refers to someone who tracks down or searches for something.

Figurative Role

The term can apply to various professions engaging in any form of tracking, like curators or detectives.

Broad Application

A tool in art and design, not to be confused with a 'tracker', which monitors movement.

Reproduction Tool

A tracer helps achieve precise duplication of patterns or designs, enhancing accuracy in creative work.

Accuracy Aid

 because it takes minutes for the tracer to circulate and changes to show up. These techniques collectively help doctors and scientists connect what happens in the brain with our behavior. But they’re also limited by how much we still don't know.

How do brain scans work?...

 that uses a radioactive tracer to track blood flow in the brain. For the bargain price of a few thousand dollars, there are clinics in the U.S. that will give you one of these SPECT scans and use the image to help diagnose your problems.