SDI Open Water Scuba Diver Practice Exam

Which of the following statements is true about buoyancy?

1. Buoyancy only occurs in freshwater.

2. Buoyancy describes an object's ability to float.

3. Buoyant objects are always heavier than water.

4. Buoyancy cannot be felt underwater.

The correct answer is: Buoyancy describes an object's ability to float.

Buoyancy describes the upward force that a fluid exerts on an object immersed in it, and it determines that object's ability to float. This force acts in opposition to the weight of the object. When an object is placed in water, if the buoyant force is greater than the object's weight, it will float; if the weight is greater, the object will sink. This principle applies regardless of the type of water, whether freshwater or saltwater, making the statement about buoyancy being limited to freshwater inaccurate. Additionally, buoyant objects are not always heavier than water; in fact, objects that float typically have a lower density than the fluid they're in. While divers do experience changes in pressure and may feel different sensations underwater, buoyancy itself is a physical property that can indeed be felt. Therefore, the understanding that buoyancy describes an object's ability to float is a fundamental concept in both physics and scuba diving.