Color-changing plastic cups work because they are coated with a special temperature-sensitive ink called thermochromic leucodye.
The Science Behind the Color Change
Here's a breakdown of how this process works:
- Thermochromic Leucodyes: These are chemicals that change color in response to temperature fluctuations. The cups are coated with these dyes.
- Temperature Sensitivity: Leucodyes are engineered to change colors at specific temperatures, generally around a 5°C (9°F) or greater change. This makes them ideal for use with hot or cold beverages.
- The Color Change Process: When the temperature of the cup changes (e.g., when a cold drink is added), the leucodye molecules rearrange, absorbing or reflecting light differently, which causes the color to appear to change.
Example
Imagine a cup that is blue at room temperature. When you pour in a cold drink, the temperature drops. This temperature change causes the thermochromic leucodyes to change their structure, and the cup might turn purple, green, or some other color. When the cup warms back up, it returns to its original blue color.
Summary
Color-changing cups utilize thermochromic leucodyes, special inks that react to temperature changes, causing a visible color shift.
