Does your analogue watch glow at night? Have you ever seen glow worms?
This week in Science Club we examined luminescence. Luminescence is the process of emitting light from a substance. Luminescent things make light when their atoms become excited in a process that needs little or no heat to make it happen. Fluorescence is a type of luminescence. Fluorescent materials produce light instantly, when the atoms inside them absorb energy and become "excited." When the atoms return to normal, in as little as a hundred-thousandth of a second, they give out the energy that excited them as tiny particles of light called photons.
The question asked this week was: Does temperature affect a glow-stick?
By placing a glow-stick at a higher temperature, it glowed more brightly very quickly, but also lost that brightness in a shorter time than the glow-sticks placed at a lower temperature. This is because the chemical reaction occurs faster when the temperature is hotter.
We also examined the properties of luminol. Luminol is the chemical that is used by forensic officers to search for traces of blood at a crime scene. It reacts with the iron in our blood and glows.
So, the next time you are playing with a glo-stick, watching a movie or television show with forensic analysis, or even looking at the time on your analogue watch at 2am, give a thought to the brilliance of luminescence.
Catherine Smith, Dominique Pather, Sarka Baiada and Callum Brown
Science Club Coordinators