An object's buoyancy determines whether it floats, sinks, or hovers. As divers, we need to understand the factors that influence our own buoyancy so that we can control it while in the water. This helps us determine when to inflate or deflate the BCD, and how much weight will be required for a dive.

After this lesson, you will be able to:

• Explain why objects float or sink.
• Define the three states of buoyancy.
• List three methods used to control buoyancy while diving.