Which metal is described as melting near human body temperature?

• A. Aluminum
• B. Gallium
• C. Mercury
• D. Gadolinium

Answer: (B)

Metals have specific melting points—the temperature at which a solid turns into a liquid. When that melting point is near human body temperature, a metal can be solid in a cool room but melt on contact with the warmth of the skin. Gallium fits this idea: its melting point is about 29.8°C, so it’s solid at room temperature but will melt when held in the hand or in contact with skin, whose temperature is around 32–35°C. That’s why it’s described as melting near human body temperature.

In contrast, aluminum needs about 660°C to melt, which is far above body heat; gadolinium melts around 1313°C, also far away from typical body temperatures. Mercury is already a liquid at room temperature, so talking about it melting in contact with the body doesn’t apply in the same way.