Remember Mood Rings? The rings promising to reveal your true mood depending on the colour the ring showed. There was even an official list of meanings that went something along the lines like this.
Black – Yikes! You’re anxious and unhappy.
Yellow – Strained.
Red – Unsettled.
Green – Neutral. Like the Swiss.
Blue – LOVE.
Purple – Relaxed and at Ease. Things are going good.
Mood rings work on detecting the temperature of the wearer and change colour depending on the temperature. It was invented in 1975 by Josh Reynolds and Maris Ambats and was considered a serious piece of jewellery when first introduced. The duo bonded liquid crystals with quartz stones set into rings. There is nothing mysterious about these gems. The liquid crystals change formation with temperature affecting the wavelength of light being reflected resulting in different colours observed at different temperatures.
There is no scientifically proven correlation between the colour of a mood ring and the emotional state of a person. I’ve tried looking for a scientific study on this and could not find anything. I also remember that the ambient temperature of the room can also affect the colour of the mood ring. I grew up in a town where the daily temperature was above 30C and mood rings were nearly always blue and being 12 years old at the time, I can safely say that there were no thoughts of love with any potential dirt covered snotty boy in my class. And when a mood ring was in an air conditioned room of 23C, it nearly always turned black.
The liquid crystals, thermochromic properties have been put to good use though. The next time you see a large fancy aquarium, have a look on the glass for a sticker thermometer. Liquid crystals are used in these to indicate the temperature of the water in the aquarium.