What is the temperature of a flotation bath?

• A. 60 C
• B. 45 C
• C. 4 C
• D. -20 C

Answer: (B)

The flotation bath is kept warm to soften the paraffin enough so tissue sections relax and lay flat on slides without wrinkling. A temperature around 45°C provides that balance: it’s warm enough to smooth the wax and relax the tissue, but not so hot that the paraffin melts excessively or the tissue becomes distorted.

Choosing 60°C would be too hot and could over-soften or distort the section; 4°C or -20°C would freeze the tissue and wax, making flattening and mounting impractical and causing damage.