Questions: Select the best experiment. Which of the following would be an effective experiment to test whether fresh water freezes at a higher temperature than salt water? Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer. a Note the air temperature each day and record whether the pond is frozen and whether the ocean is frozen. b Physically isolate an area of ocean water that is the size of the freshwater pond and measure air temperature and whether each body of water is frozen. c Using distilled water and water with salt dissolved in it, try to freeze both samples in a freezer at several different temperatures and observe whether fresh water freezes at higher temperatures. d Use a large barrier to eliminate the current and waves in the ocean to ensure that these conditions are identical with those in the pond and then measure air temperature and whether each body of water is frozen.

The answer is the third one (c): Using distilled water and water with salt dissolved in it, try to freeze both samples in a freezer at several different temperatures and observe whether fresh water freezes at higher temperatures.

Explanation for each option:

a. Note the air temperature each day and record whether the pond is frozen and whether the ocean is frozen.

• This option is not effective because it does not control for variables such as the size, depth, and salinity of the bodies of water. It also does not directly test the freezing point of fresh versus salt water under controlled conditions.

b. Physically isolate an area of ocean water that is the size of the freshwater pond and measure air temperature and whether each body of water is frozen.

• While this option attempts to control for size, it still does not directly test the freezing point of fresh versus salt water. It also involves complex logistics and does not account for other environmental factors.

c. Using distilled water and water with salt dissolved in it, try to freeze both samples in a freezer at several different temperatures and observe whether fresh water freezes at higher temperatures.

• This is the best option because it directly tests the hypothesis under controlled conditions. By using distilled water and salt water in a freezer, you can accurately measure the freezing points of both and determine if fresh water freezes at a higher temperature.

d. Use a large barrier to eliminate the current and waves in the ocean to ensure that these conditions are identical with those in the pond and then measure air temperature and whether each body of water is frozen.

• This option is impractical and does not directly test the freezing point of fresh versus salt water. It focuses on environmental conditions rather than the intrinsic properties of the water types.

In summary, option c is the most effective experiment because it isolates the variable of interest (the freezing point of fresh versus salt water) and tests it under controlled conditions.