Which of the following types of water would be the densest?

• A. Cold freshwater
• B. Cold seawater
• C. Warm seawater
• D. Warm freshwater

Answer: (B)

Verified step by step guidance

1. Understand that the density of water depends on both temperature and salinity. Generally, colder water is denser than warmer water, and saltwater is denser than freshwater due to the dissolved salts increasing mass per unit volume.
2. Compare cold freshwater and warm freshwater: cold freshwater is denser because density decreases as temperature increases.
3. Compare freshwater and seawater at the same temperature: seawater is denser because dissolved salts add to the mass without significantly increasing volume.
4. Combine both factors: cold seawater is denser than warm seawater (due to temperature) and denser than cold freshwater (due to salinity).
5. Conclude that among the options, cold seawater is the densest because it has both low temperature and high salinity, which both increase density.