This generates an upward (buoyant) force on the air, as it is lighter than an equal volume of unheated air. Since most sunlight penetrates to the ground, during the day air near the ground is ...

There are two forces acting on the life jacket - its weight and the force of the water pushing ... Things that float are buoyant. If the weight is greater than the upthrust, it sinks.

It explains how objects float based on the displacement of water and the balance between gravitational force and buoyant ...