/oss/taxonomy/term/3234/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 /oss/article/did-you-know-technology/you-can-see-division-east-and-west-berlin-space <p><span>Berlin might be united now, but evidence of its 40-year history of division still remains. </span></p> <p><span> </span><img src="https://lh3.googleusercontent.com/Of7WbrP7AmRY7gy93rYDd7rtbR2fwC-bY68xDcdmoJoAKrvmNrRhSDXhmGBJDsF-nb7RNR1sSyR2mbbkOYB9OpBZx4LMNWK2kWGhLf8oF6BBKl49VMucytz_efl85vlDE3J5xCwy" style="border:none; width:600px; height:906px" /></p> <p><span>This photo, </span><a href="https://twitter.com/cmdr_hadfield/status/324638635766980608?lang=en">taken by Commander Chris Hadfield</a>, shows a divided Berlin, with the East appearing orange and the West white. But why?</p> Wed, 30 May 2018 19:40:00 +0000 Ada McVean B.Sc. 7122 at /oss