Which material changes colour in response to temperature changes?

• A. Thermochromic ink
• B. Nitinol
• C. Micro encapsulation
• D. Smart fibres

Answer: (A)

Temperature-driven color change is a property of thermochromic materials. Thermochromic ink contains pigments that alter their molecular structure as the temperature crosses a threshold, producing a visible color shift that is usually reversible as the temperature changes. This directly matches the requirement of color change in response to temperature. The other options don’t inherently change color with heat: Nitinol changes shape with temperature, not color; micro encapsulation is a packaging/processing technique; smart fibres are textiles with responsive properties, which may include color change in some cases but aren’t defined by temperature-triggered color change like thermochromic ink.