## Conceptual Physics (12th Edition)

Published by Addison-Wesley

# Chapter 15 - Reading Check Questions (Comprehension): 30

#### Answer

When surface water is cooled to $4^{\circ} C$ it is at its densest, and sinks downward, to be replaced by warmer water. Only when all of the lake water reaches $4^{\circ} C$, and is as dense as the surface water, does surface water remain there to freeze.

#### Work Step by Step

This is discussed on page 296, and shown in Figure 15.23.

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.