Everyone can guess another persons mood by the look on their face, but mood rings are believed to show what they are actually feeling. Mood rings have been around since 1975. Creators Joshua Reynolds and Maris Ambats created the stone ring to allow people to see what they are feeling inside. Each color represents a different mood: violet means happy or romantic, blue is calm, green is neutral, yellow is nervous or enthusiastic, and brown is nervous.
As a kid I always thought the mood ring could actually tell my mood, until I noticed the colors sometimes didn’t match up with it. The pebble in the ring is filled with thermo chronic liquid crystals. As a person’s mood changes, the temperatures of our bodies do also. The crystals in the ring absorb energy based on our temperature, which causes the ring the change in color. At a persons standard body temperature the ring is either blue or green. When a 
person is really stressed or thrilled blood flow moves to their organs rather than around the body, which makes our fingers cooler. The cool temperature of our fingers causes the ring to turn yellow. If a person is in the freezing cold the ring can even turn black.
Overall, the color of the stone in the ring is based of your body temperature. The colder you are the colder the ring is, while the warmer you are the warmer the ring is. Another surprising fact is that mood rings are affected more by your surrounding temperature than the actual temperature of oneself.
Mood rings definitely do not show the actual mood of a person, despite which most of 
us thought as a child but they are still very popular. They are most popular with elementary school kids, but definitely not a reliable source of ones mood.
Work Cited
http://chemistry.about.com/od/chemistryfaqs/f/moodring.htm
http://entertainment.howstuffworks.com/question443.htm
http://humantouchofchemistry.com/how-do-mood-rings-work.htm
http://wonderopolis.org/wonder/how-do-mood-rings-work/
When i was growing up mood rings were such a big thing. Everyone seemed to have one at some point of time just because it was very cool to have. I unfortunately had a bad experience with a mood changing ring, it changed my finger a different color. However, the concept is very addictive and lead me down the path of investing money in color changing nail polish, i obviously never learn my lesson
First of all, thank you for ruining my childhood! But, this was actually really interesting. I thought they just changed color for the hell of it. I didn’t know they actually changed color based on the temperature they were exposed to. Even though, the internet says mood rings don’t work I would still want to see scientists conduct a study to test it. For example, they could randomly select a group of people and expose them to different scenarios which are designed to evoke different emotions ( joy, anger, sadness etc.) and have the participants write down the emotion they felt and if the ring changed accordingly. Based on the results of the study they could see if the rings actually worked or not. But, emotion is a very hard thing to measure/ extract from people so this could be a tricky thing to test.