What makes a life preserver effective in water?

A life preserver is designed primarily for buoyancy, allowing individuals to stay afloat in water, which is crucial for survival in aquatic emergencies. The effectiveness of a life preserver stems from its ability to provide sufficient buoyant force to support a person's weight, ensuring that they remain above the water surface. Additionally, the design of the life preserver is essential; it needs to allow for easy handling, quick deployment, and comfort for the user.

While color, material, weight, and shape may have certain roles in the overall functionality of a life preserver, they do not directly address the primary functions of keeping someone afloat and safe in the water. Therefore, buoyancy and design are the most critical factors in determining the effectiveness of a life preserver.