We’ve all experienced a mood ring change color when you put it on your finger. But have you ever seen slime do that? Thermochromism is the property of substances to change color due to a change in temperature. Here is a DIY to make your own thermochromic slime.
What you need:
- ¼ cup white glue
- 1 tablespoon water
- 3 teaspoons thermochromic pigment
- ¼ cup liquid starch
- Food coloring
Mix all of the ingredients together and there you have it! (If it is very sticky, add more starch until it doesn’t stick anymore.) You just made your very own heat sensitive color changing slime. But how does it work?
There are two types of thermochromic materials. The first is liquid crystals. The temperature change causes a movement in the crystals which changes their spacing. The change in spacing causes light in the crystal to refract at different wavelengths than before. Refraction is the change in direction of propagation of any wave as a result of its traveling at different speeds at different points along the wave front.
The second type of thermochromic material is called a Leuco dye. A temperature change causes the dyes to change their molecular structures. A change in molecular structure will cause the dye to reflect different colored light. Reflection is the throwing back by a body or surface of light, heat, or sound without absorbing it.
Your thermochromic slime uses Leuco dyes to show the difference in temperature when you play with it. Can you think of anything else to use to manipulate it’s color? What happens when there is an extreme temperature change?
Written by: Mimi Garai