/oss/taxonomy/term/6259/all en /oss/article/student-contributors-general-science/brightening-traffic <p>Red signifies danger in many cultures. From a distance, green is highly visible by day. At night, yellow is easier to see. That briefly explains the <i>choice</i> of colours on every traffic light. But what makes lights <i>emit</i> those colours in the first place?</p> Thu, 12 May 2022 15:41:45 +0000 Haleh Cohn 9110 at /oss