Mood ring

For the Mýa album, see Moodring.

A mood ring shown face front. Note the band of color change.

A mood ring is a ring which contains a thermochromic element, such as liquid crystal. The ring changes color in response to the body temperature of its wearer. The color is said, by some proponents, to indicate the emotional state of the wearer.

Function

The mood ring is a metal ring ornamented with a faux gemstone (usually made of quartz or glass) which is actually either a clear capsule filled with liquid crystals, or a clear solid object with a thin sheet of liquid crystals sealed underneath. Changes in ambient temperature cause the molecules of liquid crystal to twist and change position, which in turn alters the wavelengths of light reflected by the crystal. This changes the visible color of the stone.

When worn on the finger, the metal ring conducts the body heat from the wearer's finger directly into the liquid crystals in the stone. This results in the stone changing color as the body changes temperature.

The crystals in a mood ring are usually calibrated to display an allegedly "neutral" color at the average human surface temperature, which is approximately 82°F (28°C). The popular pseudoscientific theory behind a mood ring is that since body heat fluctuates with the emotional state of the wearer, the visible indicator of body temperature will indicate how above or below an "average" emotional state a person is.

Since the color of the ring depends mainly on ambient air temperature and (to a much smaller degree) the wearer's body temperature, any claim to be able to attach particular moods to particular colors is not likely to be correct. A mood ring is basically a Liquid crystal thermometer.

References

• How Stuff Works: How do mood rings work? - Includes one list of what the colors are said to represent.
• Helium.com: How Mood Rings Work
• Liquid crystal thermometers