How to Make Your Mood Ring Black

Freeze a cold pack. Use a hard plastic cold pack typically used to keep items cold in a lunch box or a cooler. A well insulated cold pack allows you to deliver cold temperatures to a surface without generating residual condensation. Leave the cold pack in the freezer for 24 hours or until the pack is completely frozen.

Place the cold pack on top of your mood ring for approximately one to two minutes. The amount of time you apply the cold pack may vary. For example, if you are wearing the ring, you may need to hold the cold pack on for a longer amount of time since the ring is next to your body heat. For best results, hold the ring at the bottom and do not touch the top area that turns color.

Remove the ice pack from the ring and quickly dry the area with the paper towel. Even though you are not using ice, a small amount of condensation may build up on top of the ring causing liquid water droplets to form. Remove the excess water to avoid damaging your ring. Don't spend too much time rubbing and drying the ring because the more body heat that comes into contact with the ring, the less the experiment will work.

Wait less than 30 seconds for the ring color to become completely black. You may see the transformation occur as you rub the ice pack on the ring. The thermotropic crystal molecules will twist and change positions to become a dark, smoky, black color.